283 lines
9.0 KiB
C++
283 lines
9.0 KiB
C++
/*
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* contrib/pgstattuple/pgstatindex.c
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*
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*
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* pgstatindex
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*
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* Copyright (c) 2006 Satoshi Nagayasu <nagayasus@nttdata.co.jp>
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*
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* Permission to use, copy, modify, and distribute this software and
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* its documentation for any purpose, without fee, and without a
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* written agreement is hereby granted, provided that the above
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* copyright notice and this paragraph and the following two
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* paragraphs appear in all copies.
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*
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,
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* INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
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* LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
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* DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS
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* IS" BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE,
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* SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*/
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#include "postgres.h"
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#include "knl/knl_variable.h"
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#include "access/heapam.h"
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#include "access/nbtree.h"
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#include "catalog/namespace.h"
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#include "funcapi.h"
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#include "miscadmin.h"
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#include "storage/buf/bufmgr.h"
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#include "utils/builtins.h"
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#include "utils/rel.h"
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#include "utils/rel_gs.h"
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extern "C" Datum pgstatindex(PG_FUNCTION_ARGS);
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extern "C" Datum pg_relpages(PG_FUNCTION_ARGS);
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PG_FUNCTION_INFO_V1(pgstatindex);
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PG_FUNCTION_INFO_V1(pg_relpages);
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#define IS_INDEX(r) ((r)->rd_rel->relkind == RELKIND_INDEX)
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#define IS_BTREE(r) ((r)->rd_rel->relam == BTREE_AM_OID)
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/* note: BlockNumber is unsigned, hence can't be negative */
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#define CHECK_RELATION_BLOCK_RANGE(rel, blkno) \
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{ \
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if (RelationGetNumberOfBlocks(rel) <= (BlockNumber)(blkno)) \
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elog(ERROR, "block number out of range"); \
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}
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/* ------------------------------------------------
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* A structure for a whole btree index statistics
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* used by pgstatindex().
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* ------------------------------------------------
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*/
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typedef struct BTIndexStat {
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uint32 version;
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uint32 level;
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BlockNumber root_blkno;
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uint64 root_pages;
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uint64 internal_pages;
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uint64 leaf_pages;
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uint64 empty_pages;
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uint64 deleted_pages;
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uint64 max_avail;
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uint64 free_space;
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uint64 fragments;
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} BTIndexStat;
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/* ------------------------------------------------------
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* pgstatindex()
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*
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* Usage: SELECT * FROM pgstatindex('t1_pkey');
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* ------------------------------------------------------
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*/
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Datum pgstatindex(PG_FUNCTION_ARGS)
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{
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text* relname = PG_GETARG_TEXT_P(0);
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Relation rel;
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RangeVar* relrv = NULL;
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Datum result;
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BlockNumber nblocks;
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BlockNumber blkno;
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BTIndexStat indexStat;
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BufferAccessStrategy bstrategy = GetAccessStrategy(BAS_BULKREAD);
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/* -- init counters -- */
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indexStat.version = 0;
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indexStat.level = 0;
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indexStat.root_blkno = 0;
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indexStat.root_pages = 0;
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indexStat.internal_pages = 0;
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indexStat.leaf_pages = 0;
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indexStat.empty_pages = 0;
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indexStat.deleted_pages = 0;
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indexStat.max_avail = 0;
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indexStat.free_space = 0;
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indexStat.fragments = 0;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), (errmsg("must be system admin to use pgstattuple functions"))));
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relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
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rel = relation_openrv(relrv, AccessShareLock);
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if (!IS_INDEX(rel) || !IS_BTREE(rel))
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elog(ERROR, "relation \"%s\" is not a btree index", RelationGetRelationName(rel));
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/*
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* Reject attempts to read non-local temporary relations; we would be
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* likely to get wrong data since we have no visibility into the owning
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* session's local buffers.
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*/
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if (RELATION_IS_OTHER_TEMP(rel))
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ereport(ERROR,
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot access temporary tables of other sessions")));
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/*
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* Read metapage
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*/
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{
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Buffer buffer = ReadBufferExtended(rel, MAIN_FORKNUM, 0, RBM_NORMAL, bstrategy);
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Page page = BufferGetPage(buffer);
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BTMetaPageData* metad = BTPageGetMeta(page);
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indexStat.version = metad->btm_version;
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indexStat.level = metad->btm_level;
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indexStat.root_blkno = metad->btm_root;
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ReleaseBuffer(buffer);
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}
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/*
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* Scan all blocks except the metapage
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*/
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nblocks = RelationGetNumberOfBlocks(rel);
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for (blkno = 1; blkno < nblocks; blkno++) {
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Buffer buffer;
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Page page;
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BTPageOpaqueInternal opaque;
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CHECK_FOR_INTERRUPTS();
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/* Read and lock buffer */
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buffer = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL, bstrategy);
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LockBuffer(buffer, BUFFER_LOCK_SHARE);
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page = BufferGetPage(buffer);
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opaque = (BTPageOpaqueInternal)PageGetSpecialPointer(page);
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/* Determine page type, and update totals */
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if (P_ISLEAF(opaque)) {
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int max_avail;
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max_avail = BLCKSZ - (BLCKSZ - ((PageHeader)page)->pd_special + SizeOfPageHeaderData);
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indexStat.max_avail += max_avail;
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indexStat.free_space += PageGetFreeSpace(page);
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indexStat.leaf_pages++;
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/*
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* If the next leaf is on an earlier block, it means a
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* fragmentation.
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*/
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if (opaque->btpo_next != P_NONE && opaque->btpo_next < blkno)
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indexStat.fragments++;
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} else if (P_ISDELETED(opaque))
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indexStat.deleted_pages++;
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else if (P_IGNORE(opaque))
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indexStat.empty_pages++;
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else if (P_ISROOT(opaque))
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indexStat.root_pages++;
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else
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indexStat.internal_pages++;
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/* Unlock and release buffer */
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LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
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ReleaseBuffer(buffer);
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}
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relation_close(rel, AccessShareLock);
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/*----------------------------
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* Build a result tuple
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*----------------------------
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*/
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{
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TupleDesc tupleDesc;
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int j;
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char* values[10];
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HeapTuple tuple;
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/* Build a tuple descriptor for our result type */
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if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
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elog(ERROR, "return type must be a row type");
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j = 0;
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values[j] = (char*)palloc(32);
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snprintf(values[j++], 32, "%d", indexStat.version);
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values[j] = (char*)palloc(32);
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snprintf(values[j++], 32, "%d", indexStat.level);
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values[j] = (char*)palloc(32);
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snprintf(values[j++],
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32,
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INT64_FORMAT,
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(indexStat.root_pages + indexStat.leaf_pages + indexStat.internal_pages + indexStat.deleted_pages +
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indexStat.empty_pages) *
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BLCKSZ);
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values[j] = (char*)palloc(32);
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snprintf(values[j++], 32, "%u", indexStat.root_blkno);
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values[j] = (char*)palloc(32);
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snprintf(values[j++], 32, INT64_FORMAT, indexStat.internal_pages);
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values[j] = (char*)palloc(32);
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snprintf(values[j++], 32, INT64_FORMAT, indexStat.leaf_pages);
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values[j] = (char*)palloc(32);
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snprintf(values[j++], 32, INT64_FORMAT, indexStat.empty_pages);
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values[j] = (char*)palloc(32);
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snprintf(values[j++], 32, INT64_FORMAT, indexStat.deleted_pages);
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values[j] = (char*)palloc(32);
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if (indexStat.max_avail > 0)
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snprintf(
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values[j++], 32, "%.2f", 100.0 - (double)indexStat.free_space / (double)indexStat.max_avail * 100.0);
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else
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snprintf(values[j++], 32, "NaN");
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values[j] = (char*)palloc(32);
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if (indexStat.leaf_pages > 0)
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snprintf(values[j++], 32, "%.2f", (double)indexStat.fragments / (double)indexStat.leaf_pages * 100.0);
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else
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snprintf(values[j++], 32, "NaN");
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tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc), values);
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result = HeapTupleGetDatum(tuple);
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}
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PG_RETURN_DATUM(result);
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}
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/* --------------------------------------------------------
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* pg_relpages()
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*
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* Get the number of pages of the table/index.
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*
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* Usage: SELECT pg_relpages('t1');
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* SELECT pg_relpages('t1_pkey');
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* --------------------------------------------------------
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*/
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Datum pg_relpages(PG_FUNCTION_ARGS)
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{
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text* relname = PG_GETARG_TEXT_P(0);
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int64 relpages;
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Relation rel;
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RangeVar* relrv = NULL;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), (errmsg("must be system admin to use pgstattuple functions"))));
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relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
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rel = relation_openrv(relrv, AccessShareLock);
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/* note: this will work OK on non-local temp tables */
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relpages = RelationGetNumberOfBlocks(rel);
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relation_close(rel, AccessShareLock);
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PG_RETURN_INT64(relpages);
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}
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