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openGauss-server/contrib/gauss_connector/deparse.cpp

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/*
* Copyright (c) 2020 Huawei Technologies Co.,Ltd.
*
* openGauss is licensed under Mulan PSL v2.
* You can use this software according to the terms and conditions of the Mulan PSL v2.
* You may obtain a copy of Mulan PSL v2 at:
*
* http://license.coscl.org.cn/MulanPSL2
*
* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
* See the Mulan PSL v2 for more details.
* ---------------------------------------------------------------------------------------
*
* IDENTIFICATION
* contrib/gauss_connector/deparse.cpp
*
* ---------------------------------------------------------------------------------------
*/
#include "postgres.h"
#include "knl/knl_variable.h"
#include "gc_fdw.h"
#include "access/heapam.h"
#include "access/htup.h"
#include "access/sysattr.h"
#include "catalog/pg_aggregate.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "commands/defrem.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "nodes/plannodes.h"
#include "optimizer/clauses.h"
#include "optimizer/prep.h"
#include "optimizer/tlist.h"
#include "optimizer/var.h"
#include "parser/parsetree.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/syscache.h"
#include "utils/typcache.h"
/*
* Global context for gcforeign_expr_walker's search of an expression tree.
*/
typedef struct foreign_glob_cxt {
PlannerInfo* root; /* global planner state */
RelOptInfo* foreignrel; /* the foreign relation we are planning for */
Relids relids; /* relids of base relations in the underlying
* scan */
} foreign_glob_cxt;
/*
* Local (per-tree-level) context for gcforeign_expr_walker's search.
* This is concerned with identifying collations used in the expression.
*/
typedef enum {
FDW_COLLATE_NONE, /* expression is of a noncollatable type, or
* it has default collation that is not
* traceable to a foreign Var */
FDW_COLLATE_SAFE, /* collation derives from a foreign Var */
FDW_COLLATE_UNSAFE /* collation is non-default and derives from
* something other than a foreign Var */
} FDWCollateState;
typedef struct foreign_loc_cxt {
Oid collation; /* OID of current collation, if any */
FDWCollateState state; /* state of current collation choice */
} foreign_loc_cxt;
/*
* Context for gcDeparseExpr
*/
typedef struct deparse_expr_cxt {
PlannerInfo* root; /* global planner state */
RelOptInfo* foreignrel; /* the foreign relation we are planning for */
RelOptInfo* scanrel; /* the underlying scan relation. Same as
* foreignrel, when that represents a join or
* a base relation. */
StringInfo buf; /* output buffer to append to */
List** params_list; /* exprs that will become remote Params */
bool coorquery; /* just for coor query */
Plan* agg; /* just for coor query */
List* str_targetlist; /* just for coor query */
char* agg_arg1;
char* agg_arg2;
List** colmap;
int map;
bool local_schema;
} deparse_expr_cxt;
#define REL_ALIAS_PREFIX "r"
/* Handy macro to add relation name qualification */
#define ADD_REL_QUALIFIER(buf, varno) appendStringInfo((buf), "%s%d.", REL_ALIAS_PREFIX, (varno))
#define ADD_UNSIGNED_REL_QUALIFIER(buf, varno) appendStringInfo((buf), "%s%u.", REL_ALIAS_PREFIX, (varno))
#define SUBQUERY_REL_ALIAS_PREFIX "s"
#define SUBQUERY_COL_ALIAS_PREFIX "c"
/*
* Functions to determine whether an expression can be evaluated safely on
* remote server.
*/
static bool gcforeign_expr_walker(Node* node, foreign_glob_cxt* glob_cxt, foreign_loc_cxt* outer_cxt);
static char* deparse_type_name(Oid type_oid, int32 typemod);
/*
* Functions to construct string representation of a node tree.
*/
static void gcdeparseTargetList(StringInfo buf, PlannerInfo* root, Index rtindex, Relation rel, bool is_returning,
Bitmapset* attrs_used, bool qualify_col, List** retrieved_attrs);
static void gcDeparseExplicitTargetList(List* tlist, List** retrieved_attrs, deparse_expr_cxt* context);
static void gcDeparseSubqueryTargetList(deparse_expr_cxt* context);
static void gcDeparseColumnRef(StringInfo buf, int varno, int varattno, PlannerInfo* root, bool qualify_col);
static void gcDeparseRelation(StringInfo buf, Relation rel, bool schema = true);
static void gcDeparseExpr(Expr* expr, deparse_expr_cxt* context);
static void gcDeparseVar(Var* node, deparse_expr_cxt* context);
static void simpleDeparseVar(Var* node, deparse_expr_cxt* context);
static void gcDeparseConst(Const* node, deparse_expr_cxt* context, int showtype);
static void gcDeparseParam(Param* node, deparse_expr_cxt* context);
static void gcDeparseArrayRef(ArrayRef* node, deparse_expr_cxt* context);
static void gcDeparseFuncExpr(FuncExpr* node, deparse_expr_cxt* context);
static void gcDeparseOpExpr(OpExpr* node, deparse_expr_cxt* context);
static void gcDeparseOperatorName(StringInfo buf, Form_pg_operator opform);
static void gcDeparseDistinctExpr(DistinctExpr* node, deparse_expr_cxt* context);
static void gcDeparseScalarArrayOpExpr(ScalarArrayOpExpr* node, deparse_expr_cxt* context);
static void gcDeparseRelabelType(RelabelType* node, deparse_expr_cxt* context);
static void gcDeparseBoolExpr(BoolExpr* node, deparse_expr_cxt* context);
static void gcDeparseNullTest(NullTest* node, deparse_expr_cxt* context);
static void gcDeparseArrayExpr(ArrayExpr* node, deparse_expr_cxt* context);
static void printRemoteParam(int paramindex, Oid paramtype, int32 paramtypmod, deparse_expr_cxt* context);
static void printRemotePlaceholder(Oid paramtype, int32 paramtypmod, deparse_expr_cxt* context);
static void gcDeparseSelectSql(List* tlist, bool is_subquery, List** retrieved_attrs, deparse_expr_cxt* context);
static void gcDeparseLockingClause(deparse_expr_cxt* context);
static void gcAppendOrderByClause(List* pathkeys, deparse_expr_cxt* context);
static void appendConditions(List* exprs, deparse_expr_cxt* context);
static void gcDeparseFromExprForRel(StringInfo buf, PlannerInfo* root, RelOptInfo* joinrel, bool use_alias,
List** params_list, bool local_schema = false);
static void gcDeparseFromExpr(List* quals, deparse_expr_cxt* context);
static void simpleDeparseAggref(Aggref* node, deparse_expr_cxt* context);
static void appendAggOrderBy(List* orderList, List* targetList, deparse_expr_cxt* context);
static void appendFunctionName(Oid funcid, deparse_expr_cxt* context);
static Node* deparseSortGroupClause(Index ref, List* tlist, bool force_colno, deparse_expr_cxt* context);
extern bool pgxc_is_expr_shippable(Expr* node, bool* has_aggs);
/*
* Helper functions
*/
static bool is_subquery_var(Var* node, RelOptInfo* foreignrel, int* relno, int* colno);
static void get_relation_column_alias_ids(Var* node, RelOptInfo* foreignrel, int* relno, int* colno);
/*
* Examine each qual clause in input_conds, and classify them into two groups,
* which are returned as two lists:
* - remote_conds contains expressions that can be evaluated remotely
* - local_conds contains expressions that can't be evaluated remotely
*/
void classifyConditions(
PlannerInfo* root, RelOptInfo* baserel, List* input_conds, List** remote_conds, List** local_conds)
{
ListCell* lc = NULL;
bool can_remote_filter = true;
foreach (lc, input_conds) {
RestrictInfo* ri = lfirst_node(RestrictInfo, lc);
if (!is_foreign_expr(root, baserel, ri->clause)) {
can_remote_filter = false;
break;
}
}
*remote_conds = NIL;
*local_conds = NIL;
foreach (lc, input_conds) {
RestrictInfo* ri = lfirst_node(RestrictInfo, lc);
if (can_remote_filter && is_foreign_expr(root, baserel, ri->clause))
*remote_conds = lappend(*remote_conds, ri);
else
*local_conds = lappend(*local_conds, ri);
}
}
/*
* Returns true if given expr is safe to evaluate on the foreign server.
*/
bool is_foreign_expr(PlannerInfo* root, RelOptInfo* baserel, Expr* expr)
{
foreign_glob_cxt glob_cxt;
foreign_loc_cxt loc_cxt;
/*
* Check that the expression consists of nodes that are safe to execute
* remotely.
*/
glob_cxt.root = root;
glob_cxt.foreignrel = baserel;
glob_cxt.relids = baserel->relids;
loc_cxt.collation = InvalidOid;
loc_cxt.state = FDW_COLLATE_NONE;
if (!gcforeign_expr_walker((Node*)expr, &glob_cxt, &loc_cxt))
return false;
/*
* If the expression has a valid collation that does not arise from a
* foreign var, the expression can not be sent over.
*/
if (loc_cxt.state == FDW_COLLATE_UNSAFE)
return false;
/*
* An expression which includes any mutable functions can't be sent over
* because its result is not stable. For example, sending now() remote
* side could cause confusion from clock offsets. Future versions might
* be able to make this choice with more granularity. (We check this last
* because it requires a lot of expensive catalog lookups.)
*/
if (contain_mutable_functions((Node*)expr))
return false;
/* OK to evaluate on the remote server */
return true;
}
/*
* Check if expression is safe to execute remotely, and return true if so.
*
* In addition, *outer_cxt is updated with collation information.
*
* We must check that the expression contains only node types we can deparse,
* that all types/functions/operators are safe to send (they are "shippable"),
* and that all collations used in the expression derive from Vars of the
* foreign table. Because of the latter, the logic is pretty close to
* assign_collations_walker() in parse_collate.c, though we can assume here
* that the given expression is valid. Note function mutability is not
* currently considered here.
*/
static bool gcforeign_expr_walker(Node* node, foreign_glob_cxt* glob_cxt, foreign_loc_cxt* outer_cxt)
{
bool check_type = true;
GcFdwRelationInfo* fpinfo = NULL;
foreign_loc_cxt inner_cxt;
Oid collation;
FDWCollateState state;
/* Need do nothing for empty subexpressions */
if (node == NULL)
return true;
/* May need server info from baserel's fdw_private struct */
fpinfo = (GcFdwRelationInfo*)(glob_cxt->foreignrel->fdw_private);
/* Set up inner_cxt for possible recursion to child nodes */
inner_cxt.collation = InvalidOid;
inner_cxt.state = FDW_COLLATE_NONE;
switch (nodeTag(node)) {
case T_Var: {
Var* var = (Var*)node;
/*
* If the Var is from the foreign table, we consider its
* collation (if any) safe to use. If it is from another
* table, we treat its collation the same way as we would a
* Param's collation, ie it's not safe for it to have a
* non-default collation.
*/
if (bms_is_member(var->varno, glob_cxt->relids) && var->varlevelsup == 0) {
/* Var belongs to foreign table */
/*
* System columns other than ctid and oid should not be
* sent to the remote, since we don't make any effort to
* ensure that local and remote values match (tableoid, in
* particular, almost certainly doesn't match).
*/
if (var->varattno < 0 && var->varattno != SelfItemPointerAttributeNumber &&
var->varattno != ObjectIdAttributeNumber)
return false;
/* Else check the collation */
collation = var->varcollid;
state = OidIsValid(collation) ? FDW_COLLATE_SAFE : FDW_COLLATE_NONE;
} else {
/* Var belongs to some other table */
collation = var->varcollid;
if (collation == InvalidOid || collation == DEFAULT_COLLATION_OID) {
/*
* It's noncollatable, or it's safe to combine with a
* collatable foreign Var, so set state to NONE.
*/
state = FDW_COLLATE_NONE;
} else {
/*
* Do not fail right away, since the Var might appear
* in a collation-insensitive context.
*/
state = FDW_COLLATE_UNSAFE;
}
}
} break;
case T_Const: {
Const* c = (Const*)node;
/*
* If the constant has nondefault collation, either it's of a
* non-builtin type, or it reflects folding of a CollateExpr.
* It's unsafe to send to the remote unless it's used in a
* non-collation-sensitive context.
*/
collation = c->constcollid;
if (collation == InvalidOid || collation == DEFAULT_COLLATION_OID)
state = FDW_COLLATE_NONE;
else
state = FDW_COLLATE_UNSAFE;
} break;
case T_Param: {
Param* p = (Param*)node;
if (PARAM_EXTERN != p->paramkind)
return false;
/*
* Collation rule is same as for Consts and non-foreign Vars.
*/
collation = p->paramcollid;
if (collation == InvalidOid || collation == DEFAULT_COLLATION_OID)
state = FDW_COLLATE_NONE;
else
state = FDW_COLLATE_UNSAFE;
} break;
case T_ArrayRef: {
ArrayRef* ar = (ArrayRef*)node;
/* Assignment should not be in restrictions. */
if (ar->refassgnexpr != NULL)
return false;
/*
* Recurse to remaining subexpressions. Since the array
* subscripts must yield (noncollatable) integers, they won't
* affect the inner_cxt state.
*/
if (!gcforeign_expr_walker((Node*)ar->refupperindexpr, glob_cxt, &inner_cxt))
return false;
if (!gcforeign_expr_walker((Node*)ar->reflowerindexpr, glob_cxt, &inner_cxt))
return false;
if (!gcforeign_expr_walker((Node*)ar->refexpr, glob_cxt, &inner_cxt))
return false;
/*
* Array subscripting should yield same collation as input,
* but for safety use same logic as for function nodes.
*/
collation = ar->refcollid;
if (collation == InvalidOid)
state = FDW_COLLATE_NONE;
else if (inner_cxt.state == FDW_COLLATE_SAFE && collation == inner_cxt.collation)
state = FDW_COLLATE_SAFE;
else if (collation == DEFAULT_COLLATION_OID)
state = FDW_COLLATE_NONE;
else
state = FDW_COLLATE_UNSAFE;
} break;
case T_FuncExpr: {
FuncExpr* fe = (FuncExpr*)node;
/*
* If function used by the expression is not shippable, it
* can't be sent to remote because it might have incompatible
* semantics on remote side.
*/
if (!is_shippable(fe->funcid, ProcedureRelationId, fpinfo))
return false;
/*
* Recurse to input subexpressions.
*/
if (!gcforeign_expr_walker((Node*)fe->args, glob_cxt, &inner_cxt))
return false;
/*
* If function's input collation is not derived from a foreign
* Var, it can't be sent to remote.
*/
if (fe->inputcollid == InvalidOid)
/* OK, inputs are all noncollatable */;
else if (inner_cxt.state != FDW_COLLATE_SAFE || fe->inputcollid != inner_cxt.collation)
return false;
/*
* Detect whether node is introducing a collation not derived
* from a foreign Var. (If so, we just mark it unsafe for now
* rather than immediately returning false, since the parent
* node might not care.)
*/
collation = fe->funccollid;
if (collation == InvalidOid)
state = FDW_COLLATE_NONE;
else if (inner_cxt.state == FDW_COLLATE_SAFE && collation == inner_cxt.collation)
state = FDW_COLLATE_SAFE;
else if (collation == DEFAULT_COLLATION_OID)
state = FDW_COLLATE_NONE;
else
state = FDW_COLLATE_UNSAFE;
} break;
case T_OpExpr:
case T_DistinctExpr: /* struct-equivalent to OpExpr */
{
OpExpr* oe = (OpExpr*)node;
/*
* Similarly, only shippable operators can be sent to remote.
* (If the operator is shippable, we assume its underlying
* function is too.)
*/
if (!is_shippable(oe->opno, OperatorRelationId, fpinfo))
return false;
/*
* Recurse to input subexpressions.
*/
if (!gcforeign_expr_walker((Node*)oe->args, glob_cxt, &inner_cxt))
return false;
/*
* If operator's input collation is not derived from a foreign
* Var, it can't be sent to remote.
*/
if (oe->inputcollid == InvalidOid)
/* OK, inputs are all noncollatable */;
else if (inner_cxt.state != FDW_COLLATE_SAFE || oe->inputcollid != inner_cxt.collation)
return false;
/* Result-collation handling is same as for functions */
collation = oe->opcollid;
if (collation == InvalidOid)
state = FDW_COLLATE_NONE;
else if (inner_cxt.state == FDW_COLLATE_SAFE && collation == inner_cxt.collation)
state = FDW_COLLATE_SAFE;
else if (collation == DEFAULT_COLLATION_OID)
state = FDW_COLLATE_NONE;
else
state = FDW_COLLATE_UNSAFE;
} break;
case T_ScalarArrayOpExpr: {
ScalarArrayOpExpr* oe = (ScalarArrayOpExpr*)node;
/*
* Again, only shippable operators can be sent to remote.
*/
if (!is_shippable(oe->opno, OperatorRelationId, fpinfo))
return false;
/*
* Recurse to input subexpressions.
*/
if (!gcforeign_expr_walker((Node*)oe->args, glob_cxt, &inner_cxt))
return false;
/*
* If operator's input collation is not derived from a foreign
* Var, it can't be sent to remote.
*/
if (oe->inputcollid == InvalidOid)
/* OK, inputs are all noncollatable */;
else if (inner_cxt.state != FDW_COLLATE_SAFE || oe->inputcollid != inner_cxt.collation)
return false;
/* Output is always boolean and so noncollatable. */
collation = InvalidOid;
state = FDW_COLLATE_NONE;
} break;
case T_RelabelType: {
RelabelType* r = (RelabelType*)node;
/*
* Recurse to input subexpression.
*/
if (!gcforeign_expr_walker((Node*)r->arg, glob_cxt, &inner_cxt))
return false;
/*
* RelabelType must not introduce a collation not derived from
* an input foreign Var (same logic as for a real function).
*/
collation = r->resultcollid;
if (collation == InvalidOid)
state = FDW_COLLATE_NONE;
else if (inner_cxt.state == FDW_COLLATE_SAFE && collation == inner_cxt.collation)
state = FDW_COLLATE_SAFE;
else if (collation == DEFAULT_COLLATION_OID)
state = FDW_COLLATE_NONE;
else
state = FDW_COLLATE_UNSAFE;
} break;
case T_BoolExpr: {
BoolExpr* b = (BoolExpr*)node;
/*
* Recurse to input subexpressions.
*/
if (!gcforeign_expr_walker((Node*)b->args, glob_cxt, &inner_cxt))
return false;
/* Output is always boolean and so noncollatable. */
collation = InvalidOid;
state = FDW_COLLATE_NONE;
} break;
case T_NullTest: {
NullTest* nt = (NullTest*)node;
/*
* Recurse to input subexpressions.
*/
if (!gcforeign_expr_walker((Node*)nt->arg, glob_cxt, &inner_cxt))
return false;
/* Output is always boolean and so noncollatable. */
collation = InvalidOid;
state = FDW_COLLATE_NONE;
} break;
case T_ArrayExpr: {
ArrayExpr* a = (ArrayExpr*)node;
/*
* Recurse to input subexpressions.
*/
if (!gcforeign_expr_walker((Node*)a->elements, glob_cxt, &inner_cxt))
return false;
/*
* ArrayExpr must not introduce a collation not derived from
* an input foreign Var (same logic as for a function).
*/
collation = a->array_collid;
if (collation == InvalidOid)
state = FDW_COLLATE_NONE;
else if (inner_cxt.state == FDW_COLLATE_SAFE && collation == inner_cxt.collation)
state = FDW_COLLATE_SAFE;
else if (collation == DEFAULT_COLLATION_OID)
state = FDW_COLLATE_NONE;
else
state = FDW_COLLATE_UNSAFE;
} break;
case T_List: {
List* l = (List*)node;
ListCell* lc = NULL;
/*
* Recurse to component subexpressions.
*/
foreach (lc, l) {
if (!gcforeign_expr_walker((Node*)lfirst(lc), glob_cxt, &inner_cxt))
return false;
}
/*
* When processing a list, collation state just bubbles up
* from the list elements.
*/
collation = inner_cxt.collation;
state = inner_cxt.state;
/* Don't apply exprType() to the list. */
check_type = false;
} break;
case T_Aggref: {
Aggref* agg = (Aggref*)node;
ListCell* lc = NULL;
/* As usual, it must be shippable. */
if (!is_shippable(agg->aggfnoid, ProcedureRelationId, fpinfo))
return false;
/*
* Recurse to input args. aggdirectargs, aggorder and
* aggdistinct are all present in args, so no need to check
* their shippability explicitly.
*/
foreach (lc, agg->args) {
Node* n = (Node*)lfirst(lc);
/* If TargetEntry, extract the expression from it */
if (IsA(n, TargetEntry)) {
TargetEntry* tle = (TargetEntry*)n;
n = (Node*)tle->expr;
}
if (!gcforeign_expr_walker(n, glob_cxt, &inner_cxt))
return false;
}
/*
* For aggorder elements, check whether the sort operator, if
* specified, is shippable or not.
*/
if (agg->aggorder) {
ListCell* lc_order = NULL;
foreach (lc_order, agg->aggorder) {
SortGroupClause* srt = (SortGroupClause*)lfirst(lc_order);
Oid sortcoltype;
TypeCacheEntry* typentry = NULL;
TargetEntry* tle = NULL;
tle = get_sortgroupref_tle(srt->tleSortGroupRef, agg->args);
sortcoltype = exprType((Node*)tle->expr);
typentry = lookup_type_cache(sortcoltype, TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
/* Check shippability of non-default sort operator. */
if (srt->sortop != typentry->lt_opr && srt->sortop != typentry->gt_opr &&
!is_shippable(srt->sortop, OperatorRelationId, fpinfo))
return false;
}
}
/*
* If aggregate's input collation is not derived from a
* foreign Var, it can't be sent to remote.
*/
if (agg->inputcollid == InvalidOid)
/* OK, inputs are all noncollatable */;
else if (inner_cxt.state != FDW_COLLATE_SAFE || agg->inputcollid != inner_cxt.collation)
return false;
/*
* Detect whether node is introducing a collation not derived
* from a foreign Var. (If so, we just mark it unsafe for now
* rather than immediately returning false, since the parent
* node might not care.)
*/
collation = agg->aggcollid;
if (collation == InvalidOid)
state = FDW_COLLATE_NONE;
else if (inner_cxt.state == FDW_COLLATE_SAFE && collation == inner_cxt.collation)
state = FDW_COLLATE_SAFE;
else if (collation == DEFAULT_COLLATION_OID)
state = FDW_COLLATE_NONE;
else
state = FDW_COLLATE_UNSAFE;
} break;
default:
/*
* If it's anything else, assume it's unsafe. This list can be
* expanded later, but don't forget to add deparse support below.
*/
return false;
}
/*
* If result type of given expression is not shippable, it can't be sent
* to remote because it might have incompatible semantics on remote side.
*/
if (check_type && !is_shippable(exprType(node), TypeRelationId, fpinfo))
return false;
/*
* Now, merge my collation information into my parent's state.
*/
if (state > outer_cxt->state) {
/* Override previous parent state */
outer_cxt->collation = collation;
outer_cxt->state = state;
} else if (state == outer_cxt->state) {
/* Merge, or detect error if there's a collation conflict */
switch (state) {
case FDW_COLLATE_NONE:
/* Nothing + nothing is still nothing */
break;
case FDW_COLLATE_SAFE:
if (collation != outer_cxt->collation) {
/*
* Non-default collation always beats default.
*/
if (outer_cxt->collation == DEFAULT_COLLATION_OID) {
/* Override previous parent state */
outer_cxt->collation = collation;
} else if (collation != DEFAULT_COLLATION_OID) {
/*
* Conflict; show state as indeterminate. We don't
* want to "return false" right away, since parent
* node might not care about collation.
*/
outer_cxt->state = FDW_COLLATE_UNSAFE;
}
}
break;
case FDW_COLLATE_UNSAFE:
/* We're still conflicted ... */
break;
}
}
/* It looks OK */
return true;
}
/*
* Convert type OID + typmod info into a type name we can ship to the remote
* server. Someplace else had better have verified that this type name is
* expected to be known on the remote end.
*
* This is almost just format_type_with_typemod(), except that if left to its
* own devices, that function will make schema-qualification decisions based
* on the local search_path, which is wrong. We must schema-qualify all
* type names that are not in pg_catalog. We assume here that built-in types
* are all in pg_catalog and need not be qualified; otherwise, qualify.
*/
static char* deparse_type_name(Oid type_oid, int32 typemod)
{
if (is_builtin(type_oid))
return format_type_with_typemod(type_oid, typemod);
else {
elog(ERROR, "unsupported data type %u", type_oid);
return NULL; /* keep compiler silence */
}
}
/*
* Build the targetlist for given relation to be deparsed as SELECT clause.
*
* The output targetlist contains the columns that need to be fetched from the
* foreign server for the given relation. If foreignrel is an upper relation,
* then the output targetlist can also contain expressions to be evaluated on
* foreign server.
*/
List* build_tlist_to_deparse(RelOptInfo* foreignrel)
{
List* tlist = NIL;
GcFdwRelationInfo* fpinfo = (GcFdwRelationInfo*)foreignrel->fdw_private;
ListCell* lc = NULL;
/*
* We require columns specified in foreignrel->reltarget->exprs and those
* required for evaluating the local conditions.
*/
tlist = foreignrel->reltargetlist;
foreach (lc, fpinfo->local_conds) {
RestrictInfo* rinfo = lfirst_node(RestrictInfo, lc);
tlist = add_to_flat_tlist(
tlist, pull_var_clause((Node*)rinfo->clause, PVC_REJECT_AGGREGATES, PVC_RECURSE_PLACEHOLDERS));
}
return tlist;
}
/*
* Deparse SELECT statement for given relation into buf.
*
* tlist contains the list of desired columns to be fetched from foreign server.
* For a base relation fpinfo->attrs_used is used to construct SELECT clause,
* hence the tlist is ignored for a base relation.
*
* remote_conds is the list of conditions to be deparsed into the WHERE clause
* (or, in the case of upper relations, into the HAVING clause).
*
* If params_list is not NULL, it receives a list of Params and other-relation
* Vars used in the clauses; these values must be transmitted to the remote
* server as parameter values.
*
* If params_list is NULL, we're generating the query for EXPLAIN purposes,
* so Params and other-relation Vars should be replaced by dummy values.
*
* pathkeys is the list of pathkeys to order the result by.
*
* is_subquery is the flag to indicate whether to deparse the specified
* relation as a subquery.
*
* List of columns selected is returned in retrieved_attrs.
*/
extern void gcDeparseSelectStmtForRel(StringInfo buf, PlannerInfo* root, RelOptInfo* rel, List* tlist,
List* remote_conds, List* pathkeys, bool is_subquery, List** retrieved_attrs, List** params_list)
{
deparse_expr_cxt context;
List* quals = NIL;
/*
* We handle relations for foreign tables, joins between those and upper
* relations.
*/
Assert(IS_JOIN_REL(rel) || IS_SIMPLE_REL(rel));
/* Fill portions of context common to upper, join and base relation */
context.buf = buf;
context.root = root;
context.foreignrel = rel;
context.scanrel = rel;
context.params_list = params_list;
context.coorquery = false;
context.local_schema = false;
/* Construct SELECT clause */
gcDeparseSelectSql(tlist, is_subquery, retrieved_attrs, &context);
quals = remote_conds;
/* Construct FROM and WHERE clauses */
gcDeparseFromExpr(quals, &context);
/* Add ORDER BY clause if we found any useful pathkeys */
if (pathkeys != NULL)
gcAppendOrderByClause(pathkeys, &context);
/* Add any necessary FOR UPDATE/SHARE. */
gcDeparseLockingClause(&context);
}
/*
* Construct a simple SELECT statement that retrieves desired columns
* of the specified foreign table, and append it to "buf". The output
* contains just "SELECT ... ".
*
* We also create an integer List of the columns being retrieved, which is
* returned to *retrieved_attrs, unless we deparse the specified relation
* as a subquery.
*
* tlist is the list of desired columns. is_subquery is the flag to
* indicate whether to deparse the specified relation as a subquery.
* Read prologue of gcDeparseSelectStmtForRel() for details.
*/
static void gcDeparseSelectSql(List* tlist, bool is_subquery, List** retrieved_attrs, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
RelOptInfo* foreignrel = context->foreignrel;
PlannerInfo* root = context->root;
GcFdwRelationInfo* fpinfo = (GcFdwRelationInfo*)foreignrel->fdw_private;
/*
* Construct SELECT list
*/
appendStringInfoString(buf, "SELECT ");
if (is_subquery) {
/*
* For a relation that is deparsed as a subquery, emit expressions
* specified in the relation's reltarget. Note that since this is for
* the subquery, no need to care about *retrieved_attrs.
*/
gcDeparseSubqueryTargetList(context);
} else if (IS_JOIN_REL(foreignrel)) {
/*
* For a join or upper relation the input tlist gives the list of
* columns required to be fetched from the foreign server.
*/
gcDeparseExplicitTargetList(tlist, retrieved_attrs, context);
} else {
/*
* For a base relation fpinfo->attrs_used gives the list of columns
* required to be fetched from the foreign server.
*/
RangeTblEntry* rte = planner_rt_fetch(foreignrel->relid, root);
/*
* Core code already has some lock on each rel being planned, so we
* can use NoLock here.
*/
Relation rel = heap_open(rte->relid, NoLock);
gcdeparseTargetList(buf, root, foreignrel->relid, rel, false, fpinfo->attrs_used, false, retrieved_attrs);
heap_close(rel, NoLock);
}
}
/*
* Construct a FROM clause and, if needed, a WHERE clause, and append those to
* "buf".
*
* quals is the list of clauses to be included in the WHERE clause.
* (These may or may not include RestrictInfo decoration.)
*/
static void gcDeparseFromExpr(List* quals, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
RelOptInfo* scanrel = context->scanrel;
/* For upper relations, scanrel must be either a joinrel or a baserel */
Assert(IS_JOIN_REL(scanrel) || IS_SIMPLE_REL(scanrel));
/* Construct FROM clause */
appendStringInfoString(buf, " FROM ");
gcDeparseFromExprForRel(buf,
context->root,
scanrel,
(bms_num_members(scanrel->relids) > 1),
context->params_list,
context->local_schema);
/* Construct WHERE clause */
if (quals != NIL) {
appendStringInfo(buf, " WHERE ");
appendConditions(quals, context);
}
}
/*
* Emit a target list that retrieves the columns specified in attrs_used.
* This is used for both SELECT and RETURNING targetlists; the is_returning
* parameter is true only for a RETURNING targetlist.
*
* The tlist text is appended to buf, and we also create an integer List
* of the columns being retrieved, which is returned to *retrieved_attrs.
*
* If qualify_col is true, add relation alias before the column name.
*/
static void gcdeparseTargetList(StringInfo buf, PlannerInfo* root, Index rtindex, Relation rel, bool is_returning,
Bitmapset* attrs_used, bool qualify_col, List** retrieved_attrs)
{
TupleDesc tupdesc = RelationGetDescr(rel);
bool have_wholerow = false;
bool first = true;
int i;
*retrieved_attrs = NIL;
/* If there's a whole-row reference, we'll need all the columns. */
have_wholerow = bms_is_member(0 - FirstLowInvalidHeapAttributeNumber, attrs_used);
for (i = 1; i <= tupdesc->natts; i++) {
Form_pg_attribute attr = tupdesc->attrs[i - 1];
/* Ignore dropped attributes. */
if (attr->attisdropped)
continue;
if (have_wholerow || bms_is_member(i - FirstLowInvalidHeapAttributeNumber, attrs_used)) {
if (!first)
appendStringInfoString(buf, ", ");
else if (is_returning)
appendStringInfoString(buf, " RETURNING ");
first = false;
gcDeparseColumnRef(buf, rtindex, i, root, qualify_col);
*retrieved_attrs = lappend_int(*retrieved_attrs, i);
}
}
/*
* Add ctid and oid if needed. We currently don't support retrieving any
* other system columns.
*/
if (bms_is_member(SelfItemPointerAttributeNumber - FirstLowInvalidHeapAttributeNumber, attrs_used)) {
if (!first)
appendStringInfoString(buf, ", ");
else if (is_returning)
appendStringInfoString(buf, " RETURNING ");
first = false;
if (qualify_col)
ADD_UNSIGNED_REL_QUALIFIER(buf, rtindex);
appendStringInfoString(buf, "ctid");
*retrieved_attrs = lappend_int(*retrieved_attrs, SelfItemPointerAttributeNumber);
}
if (bms_is_member(ObjectIdAttributeNumber - FirstLowInvalidHeapAttributeNumber, attrs_used)) {
if (!first)
appendStringInfoString(buf, ", ");
else if (is_returning)
appendStringInfoString(buf, " RETURNING ");
first = false;
if (qualify_col)
ADD_UNSIGNED_REL_QUALIFIER(buf, rtindex);
appendStringInfoString(buf, "oid");
*retrieved_attrs = lappend_int(*retrieved_attrs, ObjectIdAttributeNumber);
}
/* Don't generate bad syntax if no undropped columns */
if (first && !is_returning)
appendStringInfoString(buf, "NULL");
}
/*
* Deparse the appropriate locking clause (FOR UPDATE or FOR SHARE) for a
* given relation (context->scanrel).
*/
static void gcDeparseLockingClause(deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
PlannerInfo* root = context->root;
RelOptInfo* rel = context->scanrel;
GcFdwRelationInfo* fpinfo = (GcFdwRelationInfo*)rel->fdw_private;
int relid = -1;
while ((relid = bms_next_member(rel->relids, relid)) >= 0) {
/*
* Ignore relation if it appears in a lower subquery. Locking clause
* for such a relation is included in the subquery if necessary.
*/
if (bms_is_member(relid, fpinfo->lower_subquery_rels))
continue;
/*
* Add FOR UPDATE/SHARE if appropriate. We apply locking during the
* initial row fetch, rather than later on as is done for local
* tables. The extra roundtrips involved in trying to duplicate the
* local semantics exactly don't seem worthwhile (see also comments
* for RowMarkType).
*
* Note: because we actually run the query as a cursor, this assumes
* that DECLARE CURSOR ... FOR UPDATE is supported, which it isn't
* before 8.3.
*/
if (relid == root->parse->resultRelation &&
(root->parse->commandType == CMD_UPDATE || root->parse->commandType == CMD_DELETE)) {
/* Relation is UPDATE/DELETE target, so use FOR UPDATE */
appendStringInfoString(buf, " FOR UPDATE");
/* Add the relation alias if we are here for a join relation */
if (IS_JOIN_REL(rel))
appendStringInfo(buf, " OF %s%d", REL_ALIAS_PREFIX, relid);
} else {
PlanRowMark* rc = get_plan_rowmark(root->rowMarks, relid);
if (rc != NULL) {
/* Add the relation alias if we are here for a join relation */
if (bms_num_members(rel->relids) > 1 /*&&
rc->strength != LCS_NONE*/)
appendStringInfo(buf, " OF %s%d", REL_ALIAS_PREFIX, relid);
}
}
}
}
/*
* Deparse conditions from the provided list and append them to buf.
*
* The conditions in the list are assumed to be ANDed. This function is used to
* deparse WHERE clauses, JOIN .. ON clauses and HAVING clauses.
*
* Depending on the caller, the list elements might be either RestrictInfos
* or bare clauses.
*/
static void appendConditions(List* exprs, deparse_expr_cxt* context)
{
int nestlevel;
ListCell* lc = NULL;
bool is_first = true;
StringInfo buf = context->buf;
/* Make sure any constants in the exprs are printed portably */
nestlevel = set_transmission_modes();
foreach (lc, exprs) {
Expr* expr = (Expr*)lfirst(lc);
/* Extract clause from RestrictInfo, if required */
if (IsA(expr, RestrictInfo))
expr = ((RestrictInfo*)expr)->clause;
/* Connect expressions with "AND" and parenthesize each condition. */
if (!is_first)
appendStringInfoString(buf, " AND ");
appendStringInfoChar(buf, '(');
gcDeparseExpr(expr, context);
appendStringInfoChar(buf, ')');
is_first = false;
}
reset_transmission_modes(nestlevel);
}
/*
* Deparse given targetlist and append it to context->buf.
*
* tlist is list of TargetEntry's which in turn contain Var nodes.
*
* retrieved_attrs is the list of continuously increasing integers starting
* from 1. It has same number of entries as tlist.
*/
static void gcDeparseExplicitTargetList(List* tlist, List** retrieved_attrs, deparse_expr_cxt* context)
{
ListCell* lc = NULL;
StringInfo buf = context->buf;
int i = 0;
*retrieved_attrs = NIL;
foreach (lc, tlist) {
TargetEntry* tle = lfirst_node(TargetEntry, lc);
if (i > 0)
appendStringInfoString(buf, ", ");
gcDeparseExpr((Expr*)tle->expr, context);
*retrieved_attrs = lappend_int(*retrieved_attrs, i + 1);
i++;
}
if (i == 0)
appendStringInfoString(buf, "NULL");
}
/*
* Emit expressions specified in the given relation's reltarget.
*
* This is used for deparsing the given relation as a subquery.
*/
static void gcDeparseSubqueryTargetList(deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
RelOptInfo* foreignrel = context->foreignrel;
bool first = true;
ListCell* lc = NULL;
/* Should only be called in these cases. */
Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
foreach (lc, foreignrel->reltargetlist) {
Node* node = (Node*)lfirst(lc);
if (!first)
appendStringInfoString(buf, ", ");
first = false;
gcDeparseExpr((Expr*)node, context);
}
/* Don't generate bad syntax if no expressions */
if (first)
appendStringInfoString(buf, "NULL");
}
/*
* Construct FROM clause for given relation
*
* The function constructs ... JOIN ... ON ... for join relation. For a base
* relation it just returns schema-qualified tablename, with the appropriate
* alias if so requested.
*/
static void gcDeparseFromExprForRel(
StringInfo buf, PlannerInfo* root, RelOptInfo* foreignrel, bool use_alias, List** params_list, bool local_schema)
{
RangeTblEntry* rte = planner_rt_fetch(foreignrel->relid, root);
/*
* Core code already has some lock on each rel being planned, so we
* can use NoLock here.
*/
Relation rel = heap_open(rte->relid, NoLock);
gcDeparseRelation(buf, rel, local_schema);
/*
* Add a unique alias to avoid any conflict in relation names due to
* pulled up subqueries in the query being built for a pushed down
* join.
*/
if (use_alias)
appendStringInfo(buf, " %s%u", REL_ALIAS_PREFIX, foreignrel->relid);
heap_close(rel, NoLock);
}
/*
* Construct name to use for given column, and emit it into buf.
* If it has a column_name FDW option, use that instead of attribute name.
*
* If qualify_col is true, qualify column name with the alias of relation.
*/
static void gcDeparseColumnRef(StringInfo buf, int varno, int varattno, PlannerInfo* root, bool qualify_col)
{
RangeTblEntry* rte = NULL;
/* We support fetching the remote side's CTID and OID. */
if (varattno == SelfItemPointerAttributeNumber) {
if (qualify_col)
ADD_REL_QUALIFIER(buf, varno);
appendStringInfoString(buf, "ctid");
} else if (varattno == ObjectIdAttributeNumber) {
if (qualify_col)
ADD_REL_QUALIFIER(buf, varno);
appendStringInfoString(buf, "oid");
} else if (varattno < 0) {
/*
* All other system attributes are fetched as 0, except for table OID,
* which is fetched as the local table OID. However, we must be
* careful; the table could be beneath an outer join, in which case it
* must go to NULL whenever the rest of the row does.
*/
Oid fetchval = 0;
if (varattno == TableOidAttributeNumber) {
rte = planner_rt_fetch(varno, root);
fetchval = rte->relid;
}
if (qualify_col) {
appendStringInfoString(buf, "CASE WHEN (");
ADD_REL_QUALIFIER(buf, varno);
appendStringInfo(buf, "*)::text IS NOT NULL THEN %u END", fetchval);
} else
appendStringInfo(buf, "%u", fetchval);
} else if (varattno == 0) {
/* Whole row reference */
Relation rel = NULL;
Bitmapset* attrs_used = NULL;
/* Required only to be passed down to gcdeparseTargetList(). */
List* retrieved_attrs = NIL;
/* Get RangeTblEntry from array in PlannerInfo. */
rte = planner_rt_fetch(varno, root);
/*
* The lock on the relation will be held by upper callers, so it's
* fine to open it with no lock here.
*/
rel = heap_open(rte->relid, NoLock);
/*
* The local name of the foreign table can not be recognized by the
* foreign server and the table it references on foreign server might
* have different column ordering or different columns than those
* declared locally. Hence we have to deparse whole-row reference as
* ROW(columns referenced locally). Construct this by deparsing a
* "whole row" attribute.
*/
attrs_used = bms_add_member(NULL, 0 - FirstLowInvalidHeapAttributeNumber);
/*
* In case the whole-row reference is under an outer join then it has
* to go NULL whenever the rest of the row goes NULL. Deparsing a join
* query would always involve multiple relations, thus qualify_col
* would be true.
*/
if (qualify_col) {
appendStringInfoString(buf, "CASE WHEN (");
ADD_REL_QUALIFIER(buf, varno);
appendStringInfo(buf, "*)::text IS NOT NULL THEN ");
}
appendStringInfoString(buf, "ROW(");
gcdeparseTargetList(buf, root, varno, rel, false, attrs_used, qualify_col, &retrieved_attrs);
appendStringInfoString(buf, ")");
/* Complete the CASE WHEN statement started above. */
if (qualify_col)
appendStringInfo(buf, " END");
heap_close(rel, NoLock);
bms_free(attrs_used);
} else {
char* colname = NULL;
List* options = NIL;
ListCell* lc = NULL;
/* varno must not be any of OUTER_VAR, INNER_VAR and INDEX_VAR. */
Assert(!IS_SPECIAL_VARNO(varno));
/* Get RangeTblEntry from array in PlannerInfo. */
rte = planner_rt_fetch(varno, root);
/*
* If it's a column of a foreign table, and it has the column_name FDW
* option, use that value.
*/
options = GetForeignColumnOptions(rte->relid, varattno);
foreach (lc, options) {
DefElem* def = (DefElem*)lfirst(lc);
if (strcmp(def->defname, "column_name") == 0) {
colname = defGetString(def);
break;
}
}
/*
* If it's a column of a regular table or it doesn't have column_name
* FDW option, use attribute name.
*/
if (colname == NULL)
colname = get_relid_attribute_name(rte->relid, varattno);
if (qualify_col)
ADD_REL_QUALIFIER(buf, varno);
appendStringInfoString(buf, quote_identifier(colname));
}
}
/*
* Append remote name of specified foreign table to buf.
* Use value of table_name FDW option (if any) instead of relation's name.
* Similarly, schema_name FDW option overrides schema name.
*/
static void gcDeparseRelation(StringInfo buf, Relation rel, bool local_schema)
{
ForeignTable* table = NULL;
const char* nspname = NULL;
const char* relname = NULL;
ListCell* lc = NULL;
/* obtain additional catalog information. */
table = GetForeignTable(RelationGetRelid(rel));
/*
* Use value of FDW options if any, instead of the name of object itself.
*/
foreach (lc, table->options) {
DefElem* def = (DefElem*)lfirst(lc);
if (strcmp(def->defname, "schema_name") == 0)
nspname = defGetString(def);
else if (strcmp(def->defname, "table_name") == 0)
relname = defGetString(def);
}
/*
* Note: we could skip printing the schema name if it's pg_catalog, but
* that doesn't seem worth the trouble.
*/
if (nspname == NULL)
nspname = get_namespace_name(RelationGetNamespace(rel));
if (relname == NULL)
relname = RelationGetRelationName(rel);
if (true == local_schema) {
relname = RelationGetRelationName(rel);
nspname = get_namespace_name(RelationGetNamespace(rel));
}
appendStringInfo(buf, "%s.%s", quote_identifier(nspname), quote_identifier(relname));
}
/*
* Append a SQL string literal representing "val" to buf.
*/
void gcDeparseStringLiteral(StringInfo buf, const char* val)
{
const char* valptr = NULL;
/*
* Rather than making assumptions about the remote server's value of
* u_sess->parser_cxt.standard_conforming_strings, always use E'foo' syntax if there are any
* backslashes. This will fail on remote servers before 8.1, but those
* are long out of support.
*/
if (strchr(val, '\\') != NULL)
appendStringInfoChar(buf, ESCAPE_STRING_SYNTAX);
appendStringInfoChar(buf, '\'');
for (valptr = val; *valptr; valptr++) {
char ch = *valptr;
if (SQL_STR_DOUBLE(ch, true))
appendStringInfoChar(buf, ch);
appendStringInfoChar(buf, ch);
}
appendStringInfoChar(buf, '\'');
}
/*
* Deparse given expression into context->buf.
*
* This function must support all the same node types that gcforeign_expr_walker
* accepts.
*
* Note: unlike ruleutils.c, we just use a simple hard-wired parenthesization
* scheme: anything more complex than a Var, Const, function call or cast
* should be self-parenthesized.
*/
static void gcDeparseExpr(Expr* node, deparse_expr_cxt* context)
{
if (node == NULL)
return;
switch (nodeTag(node)) {
case T_Var:
if (context->coorquery)
simpleDeparseVar((Var*)node, context);
else
gcDeparseVar((Var*)node, context);
break;
case T_Const:
gcDeparseConst((Const*)node, context, 0);
break;
case T_Param:
gcDeparseParam((Param*)node, context);
break;
case T_ArrayRef:
gcDeparseArrayRef((ArrayRef*)node, context);
break;
case T_FuncExpr:
gcDeparseFuncExpr((FuncExpr*)node, context);
break;
case T_OpExpr:
gcDeparseOpExpr((OpExpr*)node, context);
break;
case T_DistinctExpr:
gcDeparseDistinctExpr((DistinctExpr*)node, context);
break;
case T_ScalarArrayOpExpr:
gcDeparseScalarArrayOpExpr((ScalarArrayOpExpr*)node, context);
break;
case T_RelabelType:
gcDeparseRelabelType((RelabelType*)node, context);
break;
case T_BoolExpr:
gcDeparseBoolExpr((BoolExpr*)node, context);
break;
case T_NullTest:
gcDeparseNullTest((NullTest*)node, context);
break;
case T_ArrayExpr:
gcDeparseArrayExpr((ArrayExpr*)node, context);
break;
case T_Aggref:
if (context->coorquery)
simpleDeparseAggref((Aggref*)node, context);
break;
default:
elog(ERROR, "unsupported expression type for deparse: %d", (int)nodeTag(node));
break;
}
}
/*
* Deparse given Var node into context->buf.
*
* If the Var belongs to the foreign relation, just print its remote name.
* Otherwise, it's effectively a Param (and will in fact be a Param at
* run time). Handle it the same way we handle plain Params --- see
* gcDeparseParam for comments.
*/
static void gcDeparseVar(Var* node, deparse_expr_cxt* context)
{
Relids relids = context->scanrel->relids;
int relno;
int colno;
/* Qualify columns when multiple relations are involved. */
bool qualify_col = (bms_num_members(relids) > 1);
/*
* If the Var belongs to the foreign relation that is deparsed as a
* subquery, use the relation and column alias to the Var provided by the
* subquery, instead of the remote name.
*/
if (is_subquery_var(node, context->scanrel, &relno, &colno)) {
appendStringInfo(context->buf, "%s%d.%s%d", SUBQUERY_REL_ALIAS_PREFIX, relno, SUBQUERY_COL_ALIAS_PREFIX, colno);
return;
}
if (bms_is_member(node->varno, relids) && node->varlevelsup == 0)
gcDeparseColumnRef(context->buf, node->varno, node->varattno, context->root, qualify_col);
else {
/* Treat like a Param */
if (context->params_list != NULL) {
int pindex = 0;
ListCell* lc = NULL;
/* find its index in params_list */
foreach (lc, *context->params_list) {
pindex++;
if (equal(node, (Node*)lfirst(lc)))
break;
}
if (lc == NULL) {
/* not in list, so add it */
pindex++;
*context->params_list = lappend(*context->params_list, node);
}
printRemoteParam(pindex, node->vartype, node->vartypmod, context);
} else {
printRemotePlaceholder(node->vartype, node->vartypmod, context);
}
}
}
/*
* Deparse given constant value into context->buf.
*
* This function has to be kept in sync with ruleutils.c's get_const_expr.
* As for that function, showtype can be -1 to never show "::typename" decoration,
* or +1 to always show it, or 0 to show it only if the constant wouldn't be assumed
* to be the right type by default.
*/
static void gcDeparseConst(Const* node, deparse_expr_cxt* context, int showtype)
{
StringInfo buf = context->buf;
Oid typoutput;
bool typIsVarlena = false;
char* extval = NULL;
bool isfloat = false;
bool needlabel = false;
if (node->constisnull) {
appendStringInfoString(buf, "NULL");
if (showtype >= 0)
appendStringInfo(buf, "::%s", deparse_type_name(node->consttype, node->consttypmod));
return;
}
getTypeOutputInfo(node->consttype, &typoutput, &typIsVarlena);
extval = OidOutputFunctionCall(typoutput, node->constvalue);
switch (node->consttype) {
case INT2OID:
case INT4OID:
case INT8OID:
case OIDOID:
case FLOAT4OID:
case FLOAT8OID:
case NUMERICOID: {
/*
* No need to quote unless it's a special value such as 'NaN'.
* See comments in get_const_expr().
*/
if (strspn(extval, "0123456789+-eE.") == strlen(extval)) {
if (extval[0] == '+' || extval[0] == '-')
appendStringInfo(buf, "(%s)", extval);
else
appendStringInfoString(buf, extval);
if (strcspn(extval, "eE.") != strlen(extval))
isfloat = true; /* it looks like a float */
} else
appendStringInfo(buf, "'%s'", extval);
} break;
case BITOID:
case VARBITOID:
appendStringInfo(buf, "B'%s'", extval);
break;
case BOOLOID:
if (strcmp(extval, "t") == 0)
appendStringInfoString(buf, "true");
else
appendStringInfoString(buf, "false");
break;
default:
gcDeparseStringLiteral(buf, extval);
break;
}
pfree(extval);
if (showtype < 0)
return;
/*
* For showtype == 0, append ::typename unless the constant will be
* implicitly typed as the right type when it is read in.
*
* XXX this code has to be kept in sync with the behavior of the parser,
* especially make_const.
*/
switch (node->consttype) {
case BOOLOID:
case INT4OID:
case UNKNOWNOID:
needlabel = false;
break;
case NUMERICOID:
needlabel = !isfloat || (node->consttypmod >= 0);
break;
default:
needlabel = true;
break;
}
if (needlabel || showtype > 0)
appendStringInfo(buf, "::%s", deparse_type_name(node->consttype, node->consttypmod));
}
/*
* Deparse given Param node.
*
* If we're generating the query "for real", add the Param to
* context->params_list if it's not already present, and then use its index
* in that list as the remote parameter number. During EXPLAIN, there's
* no need to identify a parameter number.
*/
static void gcDeparseParam(Param* node, deparse_expr_cxt* context)
{
if (context->params_list != NULL) {
int pindex = 0;
ListCell* lc = NULL;
/* find its index in params_list */
foreach (lc, *context->params_list) {
pindex++;
if (equal(node, (Node*)lfirst(lc)))
break;
}
if (lc == NULL) {
/* not in list, so add it */
pindex++;
*context->params_list = lappend(*context->params_list, node);
}
printRemoteParam(pindex, node->paramtype, node->paramtypmod, context);
} else {
printRemotePlaceholder(node->paramtype, node->paramtypmod, context);
}
}
/*
* Deparse an array subscript expression.
*/
static void gcDeparseArrayRef(ArrayRef* node, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
ListCell* lowlist_item = NULL;
ListCell* uplist_item = NULL;
/* Always parenthesize the expression. */
appendStringInfoChar(buf, '(');
/*
* Deparse referenced array expression first. If that expression includes
* a cast, we have to parenthesize to prevent the array subscript from
* being taken as typename decoration. We can avoid that in the typical
* case of subscripting a Var, but otherwise do it.
*/
if (IsA(node->refexpr, Var))
gcDeparseExpr(node->refexpr, context);
else {
appendStringInfoChar(buf, '(');
gcDeparseExpr(node->refexpr, context);
appendStringInfoChar(buf, ')');
}
/* Deparse subscript expressions. */
lowlist_item = list_head(node->reflowerindexpr); /* could be NULL */
foreach (uplist_item, node->refupperindexpr) {
appendStringInfoChar(buf, '[');
if (lowlist_item != NULL) {
gcDeparseExpr((Expr*)lfirst(lowlist_item), context);
appendStringInfoChar(buf, ':');
lowlist_item = lnext(lowlist_item);
}
gcDeparseExpr((Expr*)lfirst(uplist_item), context);
appendStringInfoChar(buf, ']');
}
appendStringInfoChar(buf, ')');
}
/*
* Deparse a function call.
*/
static void gcDeparseFuncExpr(FuncExpr* node, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
bool use_variadic = false;
bool first = true;
ListCell* arg = NULL;
/*
* If the function call came from an implicit coercion, then just show the
* first argument.
*/
if (node->funcformat == COERCE_IMPLICIT_CAST && context->coorquery == false) {
gcDeparseExpr((Expr*)linitial(node->args), context);
return;
}
/*
* If the function call came from a cast, then show the first argument
* plus an explicit cast operation.
*/
if (node->funcformat == COERCE_EXPLICIT_CAST ||
(node->funcformat == COERCE_IMPLICIT_CAST && context->coorquery == true)) {
Oid rettype = node->funcresulttype;
int32 coercedTypmod = -1;
/* Get the typmod if this is a length-coercion function */
(void)exprIsLengthCoercion((Node*)node, &coercedTypmod);
gcDeparseExpr((Expr*)linitial(node->args), context);
appendStringInfo(buf, "::%s", deparse_type_name(rettype, coercedTypmod));
return;
}
/* Check if need to print VARIADIC (cf. ruleutils.c) */
use_variadic = node->funcvariadic;
/*
* Normal function: display as proname(args).
*/
appendFunctionName(node->funcid, context);
appendStringInfoChar(buf, '(');
/* ... and all the arguments */
foreach (arg, node->args) {
if (!first)
appendStringInfoString(buf, ", ");
if (use_variadic && lnext(arg) == NULL)
appendStringInfoString(buf, "VARIADIC ");
gcDeparseExpr((Expr*)lfirst(arg), context);
first = false;
}
appendStringInfoChar(buf, ')');
}
/*
* Deparse given operator expression. To avoid problems around
* priority of operations, we always parenthesize the arguments.
*/
static void gcDeparseOpExpr(OpExpr* node, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
HeapTuple tuple = NULL;
Form_pg_operator form = NULL;
char oprkind;
ListCell* arg = NULL;
/* Retrieve information about the operator from system catalog. */
tuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(node->opno));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for operator %u", node->opno);
form = (Form_pg_operator)GETSTRUCT(tuple);
oprkind = form->oprkind;
/* Sanity check. */
Assert((oprkind == 'r' && list_length(node->args) == 1) || (oprkind == 'l' && list_length(node->args) == 1) ||
(oprkind == 'b' && list_length(node->args) == 2));
/* Always parenthesize the expression. */
appendStringInfoChar(buf, '(');
/* Deparse left operand. */
if (oprkind == 'r' || oprkind == 'b') {
arg = list_head(node->args);
gcDeparseExpr((Expr*)lfirst(arg), context);
appendStringInfoChar(buf, ' ');
}
/* Deparse operator name. */
gcDeparseOperatorName(buf, form);
/* Deparse right operand. */
if (oprkind == 'l' || oprkind == 'b') {
arg = list_tail(node->args);
appendStringInfoChar(buf, ' ');
gcDeparseExpr((Expr*)lfirst(arg), context);
}
appendStringInfoChar(buf, ')');
ReleaseSysCache(tuple);
}
/*
* Print the name of an operator.
*/
static void gcDeparseOperatorName(StringInfo buf, Form_pg_operator opform)
{
char* opname = NULL;
/* opname is not a SQL identifier, so we should not quote it. */
opname = NameStr(opform->oprname);
/* Print schema name only if it's not pg_catalog */
if (opform->oprnamespace != PG_CATALOG_NAMESPACE) {
const char* opnspname = NULL;
opnspname = get_namespace_name(opform->oprnamespace);
/* Print fully qualified operator name. */
if (opnspname != NULL) {
appendStringInfo(buf, "OPERATOR(%s.%s)", quote_identifier(opnspname), opname);
} else {
appendStringInfo(buf, "OPERATOR(\"Unknown\".%s)", opname);
}
} else {
/* Just print operator name. */
appendStringInfoString(buf, opname);
}
}
/*
* Deparse IS DISTINCT FROM.
*/
static void gcDeparseDistinctExpr(DistinctExpr* node, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
Assert(list_length(node->args) == 2);
appendStringInfoChar(buf, '(');
gcDeparseExpr((Expr*)linitial(node->args), context);
appendStringInfoString(buf, " IS DISTINCT FROM ");
gcDeparseExpr((Expr*)lsecond(node->args), context);
appendStringInfoChar(buf, ')');
}
/*
* Deparse given ScalarArrayOpExpr expression. To avoid problems
* around priority of operations, we always parenthesize the arguments.
*/
static void gcDeparseScalarArrayOpExpr(ScalarArrayOpExpr* node, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
HeapTuple tuple = NULL;
Form_pg_operator form = NULL;
Expr* arg1 = NULL;
Expr* arg2 = NULL;
/* Retrieve information about the operator from system catalog. */
tuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(node->opno));
if (!HeapTupleIsValid(tuple)) {
elog(ERROR, "cache lookup failed for operator %u", node->opno);
}
form = (Form_pg_operator)GETSTRUCT(tuple);
/* Sanity check. */
Assert(list_length(node->args) == 2);
/* Always parenthesize the expression. */
appendStringInfoChar(buf, '(');
/* Deparse left operand. */
arg1 = (Expr*)linitial(node->args);
gcDeparseExpr(arg1, context);
appendStringInfoChar(buf, ' ');
/* Deparse operator name plus decoration. */
gcDeparseOperatorName(buf, form);
appendStringInfo(buf, " %s (", node->useOr ? "ANY" : "ALL");
/* Deparse right operand. */
arg2 = (Expr*)lsecond(node->args);
gcDeparseExpr(arg2, context);
appendStringInfoChar(buf, ')');
/* Always parenthesize the expression. */
appendStringInfoChar(buf, ')');
ReleaseSysCache(tuple);
}
/*
* Deparse a RelabelType (binary-compatible cast) node.
*/
static void gcDeparseRelabelType(RelabelType* node, deparse_expr_cxt* context)
{
gcDeparseExpr(node->arg, context);
if (node->relabelformat != COERCE_IMPLICIT_CAST)
appendStringInfo(context->buf, "::%s", deparse_type_name(node->resulttype, node->resulttypmod));
}
/*
* Deparse a BoolExpr node.
*/
static void gcDeparseBoolExpr(BoolExpr* node, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
const char* op = NULL; /* keep compiler quiet */
bool first = true;
ListCell* lc = NULL;
switch (node->boolop) {
case AND_EXPR:
op = "AND";
break;
case OR_EXPR:
op = "OR";
break;
case NOT_EXPR:
appendStringInfoString(buf, "(NOT ");
gcDeparseExpr((Expr*)linitial(node->args), context);
appendStringInfoChar(buf, ')');
return;
}
appendStringInfoChar(buf, '(');
foreach (lc, node->args) {
if (!first)
appendStringInfo(buf, " %s ", op);
gcDeparseExpr((Expr*)lfirst(lc), context);
first = false;
}
appendStringInfoChar(buf, ')');
}
/*
* Deparse IS [NOT] NULL expression.
*/
static void gcDeparseNullTest(NullTest* node, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
appendStringInfoChar(buf, '(');
gcDeparseExpr(node->arg, context);
/*
* For scalar inputs, we prefer to print as IS [NOT] NULL, which is
* shorter and traditional. If it's a rowtype input but we're applying a
* scalar test, must print IS [NOT] DISTINCT FROM NULL to be semantically
* correct.
*/
if (node->argisrow || !type_is_rowtype(exprType((Node*)node->arg))) {
if (node->nulltesttype == IS_NULL)
appendStringInfoString(buf, " IS NULL)");
else
appendStringInfoString(buf, " IS NOT NULL)");
} else {
if (node->nulltesttype == IS_NULL)
appendStringInfoString(buf, " IS NOT DISTINCT FROM NULL)");
else
appendStringInfoString(buf, " IS DISTINCT FROM NULL)");
}
}
/*
* Deparse ARRAY[...] construct.
*/
static void gcDeparseArrayExpr(ArrayExpr* node, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
bool first = true;
ListCell* lc = NULL;
appendStringInfoString(buf, "ARRAY[");
foreach (lc, node->elements) {
if (!first)
appendStringInfoString(buf, ", ");
gcDeparseExpr((Expr*)lfirst(lc), context);
first = false;
}
appendStringInfoChar(buf, ']');
/* If the array is empty, we need an explicit cast to the array type. */
if (node->elements == NIL)
appendStringInfo(buf, "::%s", deparse_type_name(node->array_typeid, -1));
}
/*
* Append ORDER BY within aggregate function.
*/
static void appendAggOrderBy(List* orderList, List* targetList, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
ListCell* lc = NULL;
bool first = true;
foreach (lc, orderList) {
SortGroupClause* srt = (SortGroupClause*)lfirst(lc);
Node* sortexpr = NULL;
Oid sortcoltype;
TypeCacheEntry* typentry = NULL;
if (!first)
appendStringInfoString(buf, ", ");
first = false;
sortexpr = deparseSortGroupClause(srt->tleSortGroupRef, targetList, false, context);
sortcoltype = exprType(sortexpr);
/* See whether operator is default < or > for datatype */
typentry = lookup_type_cache(sortcoltype, TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
if (srt->sortop == typentry->lt_opr)
appendStringInfoString(buf, " ASC");
else if (srt->sortop == typentry->gt_opr)
appendStringInfoString(buf, " DESC");
else {
HeapTuple opertup = NULL;
Form_pg_operator operform = NULL;
appendStringInfoString(buf, " USING ");
/* Append operator name. */
opertup = SearchSysCache1(OPEROID, ObjectIdGetDatum(srt->sortop));
if (!HeapTupleIsValid(opertup)) {
elog(ERROR, "cache lookup failed for operator %u", srt->sortop);
}
operform = (Form_pg_operator)GETSTRUCT(opertup);
gcDeparseOperatorName(buf, operform);
ReleaseSysCache(opertup);
}
if (srt->nulls_first)
appendStringInfoString(buf, " NULLS FIRST");
else
appendStringInfoString(buf, " NULLS LAST");
}
}
/*
* Print the representation of a parameter to be sent to the remote side.
*
* Note: we always label the Param's type explicitly rather than relying on
* transmitting a numeric type OID in PQexecParams(). This allows us to
* avoid assuming that types have the same OIDs on the remote side as they
* do locally --- they need only have the same names.
*/
static void printRemoteParam(int paramindex, Oid paramtype, int32 paramtypmod, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
char* ptypename = deparse_type_name(paramtype, paramtypmod);
appendStringInfo(buf, "$%d::%s", paramindex, ptypename);
}
/*
* Print the representation of a placeholder for a parameter that will be
* sent to the remote side at execution time.
*
* This is used when we're just trying to EXPLAIN the remote query.
* We don't have the actual value of the runtime parameter yet, and we don't
* want the remote planner to generate a plan that depends on such a value
* anyway. Thus, we can't do something simple like "$1::paramtype".
* Instead, we emit "((SELECT null::paramtype)::paramtype)".
* In all extant versions of openGauss, the planner will see that as an unknown
* constant value, which is what we want. This might need adjustment if we
* ever make the planner flatten scalar subqueries. Note: the reason for the
* apparently useless outer cast is to ensure that the representation as a
* whole will be parsed as an a_expr and not a select_with_parens; the latter
* would do the wrong thing in the context "x = ANY(...)".
*/
static void printRemotePlaceholder(Oid paramtype, int32 paramtypmod, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
char* ptypename = deparse_type_name(paramtype, paramtypmod);
appendStringInfo(buf, "((SELECT null::%s)::%s)", ptypename, ptypename);
}
/*
* Deparse ORDER BY clause according to the given pathkeys for given base
* relation. From given pathkeys expressions belonging entirely to the given
* base relation are obtained and deparsed.
*/
static void gcAppendOrderByClause(List* pathkeys, deparse_expr_cxt* context)
{
ListCell* lcell = NULL;
int nestlevel;
char* delim = " ";
RelOptInfo* baserel = context->scanrel;
StringInfo buf = context->buf;
/* Make sure any constants in the exprs are printed portably */
nestlevel = set_transmission_modes();
appendStringInfo(buf, " ORDER BY");
foreach (lcell, pathkeys) {
PathKey* pathkey = (PathKey*)lfirst(lcell);
Expr* em_expr = NULL;
em_expr = find_em_expr_for_rel(pathkey->pk_eclass, baserel);
Assert(em_expr != NULL);
appendStringInfoString(buf, delim);
gcDeparseExpr(em_expr, context);
if (pathkey->pk_strategy == BTLessStrategyNumber)
appendStringInfoString(buf, " ASC");
else
appendStringInfoString(buf, " DESC");
if (pathkey->pk_nulls_first)
appendStringInfoString(buf, " NULLS FIRST");
else
appendStringInfoString(buf, " NULLS LAST");
delim = ", ";
}
reset_transmission_modes(nestlevel);
}
/*
* appendFunctionName
* Deparses function name from given function oid.
*/
static void appendFunctionName(Oid funcid, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
HeapTuple proctup = NULL;
Form_pg_proc procform = NULL;
const char* proname = NULL;
proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
if (!HeapTupleIsValid(proctup))
elog(ERROR, "cache lookup failed for function %u", funcid);
procform = (Form_pg_proc)GETSTRUCT(proctup);
/* Print schema name only if it's not pg_catalog */
if (procform->pronamespace != PG_CATALOG_NAMESPACE) {
const char* schemaname = NULL;
schemaname = get_namespace_name(procform->pronamespace);
appendStringInfo(buf, "%s.", quote_identifier(schemaname));
}
/* Always print the function name */
proname = NameStr(procform->proname);
appendStringInfo(buf, "%s", quote_identifier(proname));
ReleaseSysCache(proctup);
}
/*
* Appends a sort or group clause.
*
* Like get_rule_sortgroupclause(), returns the expression tree, so caller
* need not find it again.
*/
static Node* deparseSortGroupClause(Index ref, List* tlist, bool force_colno, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
TargetEntry* tle = NULL;
Expr* expr = NULL;
tle = get_sortgroupref_tle(ref, tlist);
expr = tle->expr;
if (force_colno) {
/* Use column-number form when requested by caller. */
Assert(!tle->resjunk);
appendStringInfo(buf, "%d", tle->resno);
} else if (expr && IsA(expr, Const)) {
/*
* Force a typecast here so that we don't emit something like "GROUP
* BY 2", which will be misconstrued as a column position rather than
* a constant.
*/
gcDeparseConst((Const*)expr, context, 1);
} else if ((expr == NULL) || IsA(expr, Var))
gcDeparseExpr(expr, context);
else {
/* Always parenthesize the expression. */
appendStringInfoString(buf, "(");
gcDeparseExpr(expr, context);
appendStringInfoString(buf, ")");
}
return (Node*)expr;
}
/*
* Returns true if given Var is deparsed as a subquery output column, in
* which case, *relno and *colno are set to the IDs for the relation and
* column alias to the Var provided by the subquery.
*/
static bool is_subquery_var(Var* node, RelOptInfo* foreignrel, int* relno, int* colno)
{
GcFdwRelationInfo* fpinfo = (GcFdwRelationInfo*)foreignrel->fdw_private;
RelOptInfo* outerrel = fpinfo->outerrel;
RelOptInfo* innerrel = fpinfo->innerrel;
/* Should only be called in these cases. */
Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
/*
* If the given relation isn't a join relation, it doesn't have any lower
* subqueries, so the Var isn't a subquery output column.
*/
if (!IS_JOIN_REL(foreignrel))
return false;
/*
* If the Var doesn't belong to any lower subqueries, it isn't a subquery
* output column.
*/
if (!bms_is_member(node->varno, fpinfo->lower_subquery_rels))
return false;
if (bms_is_member(node->varno, outerrel->relids)) {
/*
* If outer relation is deparsed as a subquery, the Var is an output
* column of the subquery; get the IDs for the relation/column alias.
*/
if (fpinfo->make_outerrel_subquery) {
get_relation_column_alias_ids(node, outerrel, relno, colno);
return true;
}
/* Otherwise, recurse into the outer relation. */
return is_subquery_var(node, outerrel, relno, colno);
} else {
Assert(bms_is_member(node->varno, innerrel->relids));
/*
* If inner relation is deparsed as a subquery, the Var is an output
* column of the subquery; get the IDs for the relation/column alias.
*/
if (fpinfo->make_innerrel_subquery) {
get_relation_column_alias_ids(node, innerrel, relno, colno);
return true;
}
/* Otherwise, recurse into the inner relation. */
return is_subquery_var(node, innerrel, relno, colno);
}
}
/*
* Get the IDs for the relation and column alias to given Var belonging to
* given relation, which are returned into *relno and *colno.
*/
static void get_relation_column_alias_ids(Var* node, RelOptInfo* foreignrel, int* relno, int* colno)
{
GcFdwRelationInfo* fpinfo = (GcFdwRelationInfo*)foreignrel->fdw_private;
int i;
ListCell* lc = NULL;
/* Get the relation alias ID */
*relno = fpinfo->relation_index;
/* Get the column alias ID */
i = 1;
foreach (lc, foreignrel->reltargetlist) {
if (equal(lfirst(lc), (Node*)node)) {
*colno = i;
return;
}
i++;
}
/* Shouldn't get here */
elog(ERROR, "unexpected expression in subquery output");
}
/*
* the string list of the targetlist of ForeignScan is used in explain command when agg
* is deparsed to remote sql.
*/
List* get_str_targetlist(List* fdw_private)
{
List* str_targetlist = (List*)list_nth(fdw_private, FdwScanPrivateStrTargetlist);
List* rs = NIL;
ListCell* lc = NULL;
foreach (lc, str_targetlist) {
Value* val = (Value*)lfirst(lc);
rs = lappend(rs, val->val.str);
}
return rs;
}
/*
* the transimition function is found in pg_aggregate.
*/
static char* getAggTransFn(Oid aggfnid)
{
HeapTuple tuple = NULL;
Form_pg_aggregate aggform = NULL;
Form_pg_proc procform = NULL;
Oid transfnid = InvalidOid;
char* transfn = NULL;
/* find transfn oid from pg_aggregate with aggfn oid */
tuple = SearchSysCache(AGGFNOID, ObjectIdGetDatum(aggfnid), 0, 0, 0);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for aggregate %u", aggfnid);
aggform = (Form_pg_aggregate)GETSTRUCT(tuple);
if (!OidIsValid(aggform->aggtransfn)) {
ReleaseSysCache(tuple);
return NULL;
}
transfnid = aggform->aggtransfn;
ReleaseSysCache(tuple);
/* find transfn name with transfn oid */
tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(transfnid));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for function %u", transfnid);
procform = (Form_pg_proc)GETSTRUCT(tuple);
transfn = (char*)pstrdup(NameStr(procform->proname));
ReleaseSysCache(tuple);
return transfn;
}
/*
* get agg function name from pg_proc.
*/
static void deparseAggFunctionName(Oid funcid, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
HeapTuple proctup = NULL;
Form_pg_proc procform = NULL;
const char* proname = NULL;
proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
if (!HeapTupleIsValid(proctup)) {
elog(ERROR, "cache lookup failed for function %u", funcid);
}
procform = (Form_pg_proc)GETSTRUCT(proctup);
/* Print schema name only if it's not pg_catalog */
if (procform->pronamespace != PG_CATALOG_NAMESPACE) {
elog(ERROR, "can not support user-defined agg function: %u", funcid);
}
/* Always print the function name */
proname = NameStr(procform->proname);
appendStringInfo(buf, "%s", quote_identifier(proname));
ReleaseSysCache(proctup);
}
/*
* deparse Var node from targetlist from agg node.
*/
static void simpleDeparseVar(Var* node, deparse_expr_cxt* context)
{
StringInfo buf = NULL;
int varno;
int varattno;
PlannerInfo* root = context->root;
if (OUTER_VAR == node->varno && 0 == node->varnoold) {
List* fscan_targetlist = context->agg->lefttree->targetlist;
if (node->varattno > list_length(fscan_targetlist)) {
elog(ERROR, "varattno is out of range in ForeignScan node.");
}
TargetEntry* te = (TargetEntry*)list_nth(fscan_targetlist, node->varattno - 1);
gcDeparseExpr(te->expr, context);
return;
}
buf = context->buf;
varno = node->varnoold;
varattno = node->varoattno;
if (varno <= 0 || varno >= root->simple_rel_array_size) {
elog(ERROR, "invalid varno found.");
}
char* colname = NULL;
/* Get RangeTblEntry from array in PlannerInfo. */
RangeTblEntry* rte = planner_rt_fetch(varno, root);
if (RTE_RELATION != rte->rtekind)
elog(ERROR, "invalid relation type found.");
colname = get_relid_attribute_name(rte->relid, varattno);
appendStringInfoString(buf, quote_identifier(colname));
}
static deparse_expr_cxt* copyDeparseContext(deparse_expr_cxt* context)
{
deparse_expr_cxt* new_context = (deparse_expr_cxt*)palloc0(sizeof(deparse_expr_cxt));
new_context->root = context->root;
new_context->foreignrel = context->foreignrel;
new_context->scanrel = context->scanrel;
new_context->buf = context->buf;
new_context->params_list = context->params_list;
new_context->coorquery = context->coorquery;
new_context->agg = context->agg;
new_context->str_targetlist = context->str_targetlist;
new_context->agg_arg1 = context->agg_arg1;
new_context->agg_arg2 = context->agg_arg2;
new_context->local_schema = context->local_schema;
return new_context;
}
static void deparseGroupByCol(Expr* expr, deparse_expr_cxt* context, bool addparenth)
{
StringInfo buf = context->buf;
if ((expr == NULL) || IsA(expr, Var))
gcDeparseExpr(expr, context);
else {
/* Always parenthesize the expression. */
if (addparenth)
appendStringInfoString(buf, "(");
gcDeparseExpr(expr, context);
if (addparenth)
appendStringInfoString(buf, ")");
}
}
static void addGroupByColinAggTargetlist(deparse_expr_cxt* context)
{
List* aggtlist = context->agg->targetlist;
List* fstlist = context->agg->lefttree->targetlist;
Agg* agg = (Agg*)context->agg;
StringInfo buf = context->buf;
for (int i = 0; i < list_length(aggtlist); i++) {
/* check targetentry that is not in grpColIdx */
TargetEntry* tle = (TargetEntry*)list_nth(aggtlist, i);
Expr* expr = tle->expr;
bool has_aggs = false;
pgxc_is_expr_shippable((Expr*)tle, &has_aggs);
if (has_aggs)
continue;
bool found = false;
StringInfo expr1_str, expr2_str;
for (int j = 0; j < agg->numCols; j++) {
AttrNumber attr_idx = agg->grpColIdx[j];
TargetEntry* fs_tle = (TargetEntry*)list_nth(fstlist, attr_idx - 1);
Expr* fs_expr = fs_tle->expr;
expr1_str = makeStringInfo();
expr2_str = makeStringInfo();
deparse_expr_cxt* cxt1 = NULL;
deparse_expr_cxt* cxt2 = NULL;
cxt1 = copyDeparseContext(context);
cxt2 = copyDeparseContext(context);
cxt1->buf = expr1_str;
cxt2->buf = expr2_str;
deparseGroupByCol(expr, cxt1, false);
deparseGroupByCol(fs_expr, cxt2, false);
if (!pg_strcasecmp(expr1_str->data, expr2_str->data)) {
found = true;
break;
}
}
if (found)
continue;
/* add the targetentry to group by clause. */
appendStringInfoString(buf, ", ");
deparseGroupByCol(expr, context, true);
}
}
/*
* append "group by" to select statement.
*/
static void deparseGroupByClause(List* tlist, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
bool first = true;
Agg* agg = (Agg*)context->agg;
if (agg->numCols <= 0)
return;
appendStringInfo(buf, " GROUP BY ");
List* fstargetlist = context->agg->lefttree->targetlist;
for (int i = 0; i < agg->numCols; i++) {
AttrNumber attr_idx = agg->grpColIdx[i];
if (!first)
appendStringInfoString(buf, ", ");
first = false;
if (attr_idx > list_length(fstargetlist))
elog(ERROR, "invalid attr number in agg->grpColIdx");
TargetEntry* tle = (TargetEntry*)list_nth(fstargetlist, attr_idx - 1);
Expr* expr = tle->expr;
deparseGroupByCol(expr, context, true);
}
addGroupByColinAggTargetlist(context);
}
/*
* deparse agg express such as distinct, ...
*/
static void simpleDeparseAggExpr(Aggref* node, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
appendStringInfoChar(buf, '(');
/* Add DISTINCT */
appendStringInfo(buf, "%s", (node->aggdistinct != NIL) ? "DISTINCT " : "");
/* aggstar can be set only in zero-argument aggregates */
if (node->aggstar) {
appendStringInfoChar(buf, '*');
} else {
ListCell* arg = NULL;
bool first = true;
int start;
int i = 1;
/* Add all the arguments */
foreach (arg, node->args) {
TargetEntry* tle = (TargetEntry*)lfirst(arg);
Node* n = (Node*)tle->expr;
if (tle->resjunk)
continue;
if (!first)
appendStringInfoString(buf, ", ");
first = false;
start = buf->len;
gcDeparseExpr((Expr*)n, context);
if (1 == i)
context->agg_arg1 = (char*)pstrdup(buf->data + start);
if (2 == i)
context->agg_arg2 = (char*)pstrdup(buf->data + start);
++i;
}
}
/* Add ORDER BY */
if (node->aggorder != NIL) {
appendStringInfoString(buf, " ORDER BY ");
appendAggOrderBy(node->aggorder, node->args, context);
}
appendStringInfoChar(buf, ')');
}
/*
* deparse express for special agg function, such as regr_sxx, regr_syy, regr_sxy ...
*/
static char* deparseAggFor6ArrayResult(Oid aggfn, char* expr1, char* expr2)
{
Assert(expr1);
Assert(expr2);
char* transfn = getAggTransFn(aggfn);
if (NULL == transfn)
elog(ERROR, "No function name found for agg func: %u", aggfn);
StringInfo result = makeStringInfo();
if (!pg_strcasecmp(transfn, "float8_regr_accum")) {
appendStringInfo(result,
"count((%s)+(%s)), sum((%s)::numeric), sum(((%s)::numeric)*((%s)::numeric)), ",
expr1,
expr2,
expr1,
expr1,
expr1);
appendStringInfo(result,
"sum((%s)::numeric), sum(((%s)::numeric)*((%s)::numeric)), sum(((%s)::numeric)*((%s)::numeric))",
expr2,
expr2,
expr2,
expr1,
expr2);
} else {
elog(ERROR, "unsupported transition function to deparse avg expr. funcname: %s", transfn);
}
pfree(transfn);
return result->data;
}
/*
* deparse express for special agg function, such as var_pop, variance, stddev...
*/
static char* deparseAggForTripleResult(Oid aggfn, char* expr)
{
char* transfn = getAggTransFn(aggfn);
if (transfn == NULL) {
elog(ERROR, "No function name found for agg func: %u", aggfn);
}
StringInfo result = makeStringInfo();
if (!pg_strcasecmp(transfn, "int8_accum") || !pg_strcasecmp(transfn, "int4_accum") ||
!pg_strcasecmp(transfn, "int2_accum") || !pg_strcasecmp(transfn, "numeric_accum")) {
appendStringInfo(
result, "count(%s), sum((%s)::numeric), sum(((%s)::numeric)*((%s)::numeric))", expr, expr, expr, expr);
} else if (!pg_strcasecmp(transfn, "float4_accum") || !pg_strcasecmp(transfn, "float8_accum")) {
appendStringInfo(result, "count(%s), sum(%s), sum((%s)*(%s))", expr, expr, expr, expr);
} else
elog(ERROR, "unsupported transition function to deparse avg expr. funcname: %s", transfn);
pfree(transfn);
return result->data;
}
/*
* deparse avg to real array[]
*/
static char* deparseAvg(Oid aggfn, char* expr, deparse_expr_cxt* context)
{
char* transfn = getAggTransFn(aggfn);
if (NULL == transfn)
elog(ERROR, "No function name found for agg func: %u", aggfn);
StringInfo result = makeStringInfo();
if (!pg_strcasecmp(transfn, "int8_avg_accum") || !pg_strcasecmp(transfn, "int4_avg_accum") ||
!pg_strcasecmp(transfn, "int2_avg_accum") || !pg_strcasecmp(transfn, "int1_avg_accum") ||
!pg_strcasecmp(transfn, "numeric_avg_accum")) {
appendStringInfo(result, "count(%s), sum((%s)::numeric)", expr, expr);
context->map = 2;
} else if (!pg_strcasecmp(transfn, "interval_accum")) {
appendStringInfo(result, "count(%s), sum(%s)", expr, expr);
context->map = 2;
} else if (!pg_strcasecmp(transfn, "float4_accum") || !pg_strcasecmp(transfn, "float8_accum")) {
appendStringInfo(result, "count(%s), sum(%s), sum((%s)*(%s))", expr, expr, expr, expr);
context->map = 3;
} else {
elog(ERROR, "unsupported transition function to deparse avg expr. funcname: %s", transfn);
}
pfree(transfn);
return result->data;
}
/*
* entry to deparse aggref node
*/
static void simpleDeparseAggref(Aggref* node, deparse_expr_cxt* context)
{
StringInfo buf = context->buf;
context->agg_arg1 = NULL;
context->agg_arg2 = NULL;
int start = buf->len;
/* get the string of expr in agg func */
simpleDeparseAggExpr(node, context);
char* expr = (char*)pstrdup(buf->data + start);
buf->data[start] = '\0';
buf->len = strlen(buf->data);
/* Find aggregate name from aggfnoid which is a pg_proc entry */
deparseAggFunctionName(node->aggfnoid, context);
char* fname = (char*)pstrdup(buf->data + start);
buf->data[start] = '\0';
buf->len = strlen(buf->data);
/* func name + (expr) */
char* func_expr = NULL;
if (!pg_strcasecmp("avg", fname)) {
func_expr = deparseAvg(node->aggfnoid, expr, context);
appendStringInfo(buf, "%s", func_expr);
} else if (!pg_strcasecmp("var_pop", fname) || !pg_strcasecmp("var_samp", fname) ||
!pg_strcasecmp("variance", fname) || !pg_strcasecmp("stddev_pop", fname) ||
!pg_strcasecmp("stddev", fname) || !pg_strcasecmp("stddev_samp", fname)) {
func_expr = deparseAggForTripleResult(node->aggfnoid, expr);
context->map = 3;
appendStringInfo(buf, "%s", func_expr);
} else if (!pg_strcasecmp("regr_sxx", fname) || !pg_strcasecmp("regr_syy", fname) ||
!pg_strcasecmp("regr_sxy", fname) || !pg_strcasecmp("regr_r2", fname) ||
!pg_strcasecmp("regr_slope", fname) || !pg_strcasecmp("corr", fname) ||
!pg_strcasecmp("covar_pop", fname) || !pg_strcasecmp("covar_samp", fname)) {
func_expr = deparseAggFor6ArrayResult(node->aggfnoid, context->agg_arg1, context->agg_arg2);
context->map = 6;
appendStringInfo(buf, "%s", func_expr);
} else if (!pg_strcasecmp("regr_avgx", fname) || !pg_strcasecmp("regr_avgy", fname) ||
!pg_strcasecmp("regr_intercept", fname)) {
func_expr = deparseAggFor6ArrayResult(node->aggfnoid, context->agg_arg2, context->agg_arg1);
context->map = 6;
appendStringInfo(buf, "%s", func_expr);
} else {
appendStringInfo(buf, "%s%s", fname, expr);
}
}
/*
* deparse the targetlist for agg node.
*/
static void deparseAggTargetList(List* tlist, deparse_expr_cxt* context)
{
ListCell* lc = NULL;
StringInfo buf = context->buf;
int start;
int i = 0;
foreach (lc, tlist) {
TargetEntry* tle = lfirst_node(TargetEntry, lc);
context->map = 1;
if (i > 0)
appendStringInfoString(buf, ", ");
i++;
start = buf->len;
gcDeparseExpr((Expr*)tle->expr, context);
char* str_target = (char*)pstrdup(buf->data + start);
Value* val = makeString(str_target);
context->str_targetlist = lappend(context->str_targetlist, val);
val = makeInteger(context->map);
*context->colmap = lappend(*context->colmap, val);
}
}
/*
* the entry to deparse agg node to remote sql in foreignscan node.
*/
static void deparseSelectStmt(StringInfo buf, PlannerInfo* root, RelOptInfo* rel, List* remote_conds, List* paramlist,
Plan* agg, List** str_targetlist, List** colmap, bool local_schema)
{
List* quals = NIL;
deparse_expr_cxt* context = (deparse_expr_cxt*)palloc0(sizeof(deparse_expr_cxt));
/* Fill portions of context common to upper, join and base relation */
context->buf = buf;
context->root = root;
context->foreignrel = rel;
context->scanrel = rel;
context->coorquery = true;
context->agg = agg;
context->agg_arg1 = NULL;
context->agg_arg2 = NULL;
context->params_list = &paramlist;
context->colmap = colmap;
context->local_schema = local_schema;
/* Construct SELECT clause */
appendStringInfoString(context->buf, "SELECT ");
deparseAggTargetList(agg->targetlist, context);
*str_targetlist = context->str_targetlist;
/*
* For upper relations, the WHERE clause is built from the remote
* conditions of the underlying scan relation; otherwise, we can use the
* supplied list of remote conditions directly.
*/
quals = remote_conds;
/* Construct FROM and WHERE clauses */
gcDeparseFromExpr(quals, context);
/* Append GROUP BY clause */
deparseGroupByClause(agg->targetlist, context);
}
static bool test_remote_sql(const char* sql)
{
if (NULL == sql)
return false;
List* query_string_locationlist = NIL;
List* parsetree_list = pg_parse_query(sql, &query_string_locationlist);
if (list_length(parsetree_list) != 0) {
Node* parsetree = (Node*)list_nth(parsetree_list, 0);
(void)pg_analyze_and_rewrite(parsetree, sql, NULL, 0);
}
return true;
}
/*
* @Description: just for cooperation analysis on client cluster,
* try to deparse agg node to remote sql in ForeignScan node.
*
* @param[IN] agg : current plan node
* @param[IN] root : PlannerInfo*
* @return: Plan*: remote sql includes agg functions, or leave unchanged
*/
Plan* deparse_agg_node(Plan* agg, PlannerInfo* root)
{
List* str_targetlist = NIL;
List* colmap = NIL;
ForeignScan* fscan = (ForeignScan*)agg->lefttree;
if (fscan->scan.scanrelid <= 0 || (int)fscan->scan.scanrelid >= root->simple_rel_array_size)
return agg;
RelOptInfo* scanrel = root->simple_rel_array[fscan->scan.scanrelid];
if (NULL == scanrel->fdwroutine || NULL == scanrel->fdw_private)
return agg;
GcFdwRelationInfo* fpinfo = (GcFdwRelationInfo*)scanrel->fdw_private;
if (fpinfo->reloid != fscan->scan_relid)
return agg;
List* remote_quals = (List*)list_nth(fscan->fdw_private, FdwScanPrivateRemoteQuals);
List* param_list = (List*)list_nth(fscan->fdw_private, FdwScanPrivateParamList);
/* deparse agg node to remote sql that includes agg functions. */
StringInfo sql = makeStringInfo();
deparseSelectStmt(sql, root, scanrel, remote_quals, param_list, agg, &str_targetlist, &colmap, false);
Assert(list_length(agg->targetlist) == list_length(colmap));
List* test_str_targetlist = NIL;
List* test_colmap = NIL;
StringInfo test_sql = makeStringInfo();
deparseSelectStmt(test_sql, root, scanrel, remote_quals, param_list, agg, &test_str_targetlist, &test_colmap, true);
if (NULL == param_list) {
if (false == test_remote_sql(test_sql->data))
return agg;
}
ereport(DEBUG1, (errmodule(MOD_COOP_ANALYZE), errmsg("remote agg sql: %s", sql->data)));
/* get the real target list of ForeignScan node to match the output of the remote sql. */
int i, j;
List* aggResultTargetList = NIL;
List* aggScanTargetList = NIL;
ListCell* lc = NULL;
for (i = 0, j = 0; i < list_length(agg->targetlist); i++) {
TargetEntry* tle = (TargetEntry*)list_nth(agg->targetlist, i);
/* the just type of Var is valid for the output of the remote sql, so varno set to 0 */
Var* var = makeVarFromTargetEntry(0, tle);
TargetEntry* newtle = makeTargetEntry((Expr*)var, i + 1, tle->resname, false);
aggResultTargetList = lappend(aggResultTargetList, newtle);
if (INT8ARRAYOID == var->vartype) {
Var* itemvar = (Var*)copyObject(var);
itemvar->vartype = INT8OID;
itemvar->vartypmod = -1;
TargetEntry* itemtle1 = makeTargetEntry((Expr*)itemvar, j++, tle->resname, false);
TargetEntry* itemtle2 = makeTargetEntry((Expr*)itemvar, j++, tle->resname, false);
aggScanTargetList = lappend(aggScanTargetList, itemtle1);
aggScanTargetList = lappend(aggScanTargetList, itemtle2);
} else if (FLOAT4ARRAYOID == var->vartype || FLOAT8ARRAYOID == var->vartype || NUMERICARRAY == var->vartype) {
Var* itemvar = (Var*)copyObject(var);
if (NUMERICARRAY == var->vartype)
itemvar->vartype = NUMERICOID;
else
itemvar->vartype = FLOAT8OID;
itemvar->vartypmod = -1;
Value* val = (Value*)list_nth(colmap, i);
long map = val->val.ival;
for (long item = 0; item < map; item++) {
TargetEntry* itemtle = makeTargetEntry((Expr*)itemvar, j++, tle->resname, false);
aggScanTargetList = lappend(aggScanTargetList, itemtle);
}
} else if (ARRAYINTERVALOID == var->vartype)
elog(ERROR, "unsupport data type in agg pushdown.");
else {
j++;
aggScanTargetList = lappend(aggScanTargetList, newtle);
}
}
/* reconstruct the fdw_private of ForeignScan node. */
i = 0;
List* newfdw_private = NIL;
foreach (lc, fscan->fdw_private) {
/* replace the remote sql with new one. */
if (FdwScanPrivateSelectSql == i) {
Value* val = makeString(sql->data);
newfdw_private = lappend(newfdw_private, val);
i++;
continue;
}
/* add the string of targetlist of foreignscan for the output of explain cmd. */
if (FdwScanPrivateStrTargetlist == i) {
newfdw_private = lappend(newfdw_private, str_targetlist);
i++;
continue;
}
/* save the agg result targetlist in fdw_private */
if (FdwScanPrivateAggResultTargetlist == i) {
newfdw_private = lappend(newfdw_private, aggResultTargetList);
i++;
continue;
}
/* save the agg scan targetlist in fdw_private */
if (FdwScanPrivateAggScanTargetlist == i) {
newfdw_private = lappend(newfdw_private, aggScanTargetList);
i++;
continue;
}
/* save the agg scan targetlist in fdw_private */
if (FdwScanPrivateAggColmap == i) {
newfdw_private = lappend(newfdw_private, colmap);
i++;
continue;
}
newfdw_private = lappend(newfdw_private, lfirst(lc));
i++;
}
fscan->fdw_private = newfdw_private;
/* if success, set agg node to be dummy */
Agg* aggplan = (Agg*)agg;
aggplan->is_dummy = true;
return agg;
}
// end of file
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