mirror of
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500 lines
12 KiB
C
500 lines
12 KiB
C
/*
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* btreefuncs.c
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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 "fmgr.h"
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#include "funcapi.h"
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#include "access/heapam.h"
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#include "access/itup.h"
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#include "access/nbtree.h"
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#include "access/transam.h"
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#include "catalog/namespace.h"
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#include "catalog/pg_type.h"
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#include "utils/builtins.h"
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#include "utils/inval.h"
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PG_FUNCTION_INFO_V1(bt_metap);
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PG_FUNCTION_INFO_V1(bt_page_items);
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PG_FUNCTION_INFO_V1(bt_page_stats);
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extern Datum bt_metap(PG_FUNCTION_ARGS);
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extern Datum bt_page_items(PG_FUNCTION_ARGS);
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extern Datum bt_page_stats(PG_FUNCTION_ARGS);
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#define BTMETAP_TYPE "public.bt_metap_type"
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#define BTMETAP_NCOLUMNS 6
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#define BTPAGEITEMS_TYPE "public.bt_page_items_type"
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#define BTPAGEITEMS_NCOLUMNS 6
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#define BTPAGESTATS_TYPE "public.bt_page_stats_type"
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#define BTPAGESTATS_NCOLUMNS 11
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#define IS_INDEX(r) ((r)->rd_rel->relkind == 'i')
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#define IS_BTREE(r) ((r)->rd_rel->relam == BTREE_AM_OID)
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#define CHECK_PAGE_OFFSET_RANGE(page, offset) { \
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if ( !(FirstOffsetNumber<=(offset) && \
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(offset)<=PageGetMaxOffsetNumber(page)) ) \
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elog(ERROR, "Page offset number out of range."); }
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#define CHECK_RELATION_BLOCK_RANGE(rel, blkno) { \
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if ( (blkno)<0 && RelationGetNumberOfBlocks((rel))<=(blkno) ) \
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elog(ERROR, "Block number out of range."); }
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/* ------------------------------------------------
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* structure for single btree page statistics
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* ------------------------------------------------
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*/
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typedef struct BTPageStat
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{
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uint32 blkno;
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uint32 live_items;
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uint32 dead_items;
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uint32 page_size;
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uint32 max_avail;
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uint32 free_size;
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uint32 avg_item_size;
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char type;
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/* opaque data */
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BlockNumber btpo_prev;
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BlockNumber btpo_next;
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union
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{
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uint32 level;
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TransactionId xact;
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} btpo;
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uint16 btpo_flags;
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BTCycleId btpo_cycleid;
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} BTPageStat;
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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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{
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uint32 magic;
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uint32 version;
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BlockNumber root_blkno;
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uint32 level;
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BlockNumber fastroot;
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uint32 fastlevel;
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uint32 live_items;
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uint32 dead_items;
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uint32 root_pages;
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uint32 internal_pages;
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uint32 leaf_pages;
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uint32 empty_pages;
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uint32 deleted_pages;
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uint32 page_size;
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uint32 avg_item_size;
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uint32 max_avail;
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uint32 free_space;
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} BTIndexStat;
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/* -------------------------------------------------
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* GetBTPageStatistics()
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*
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* Collect statistics of single b-tree leaf page
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* -------------------------------------------------
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*/
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static void
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GetBTPageStatistics(BlockNumber blkno, Buffer buffer, BTPageStat * stat)
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{
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Page page = BufferGetPage(buffer);
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PageHeader phdr = (PageHeader) page;
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OffsetNumber maxoff = PageGetMaxOffsetNumber(page);
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BTPageOpaque opaque = (BTPageOpaque) PageGetSpecialPointer(page);
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int item_size = 0;
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int off;
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stat->blkno = blkno;
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stat->max_avail = BLCKSZ - (BLCKSZ - phdr->pd_special + SizeOfPageHeaderData);
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stat->dead_items = stat->live_items = 0;
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stat->page_size = PageGetPageSize(page);
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/* page type (flags) */
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if (P_ISDELETED(opaque))
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{
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stat->type = 'd';
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stat->btpo.xact = opaque->btpo.xact;
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return;
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}
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else if (P_IGNORE(opaque))
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stat->type = 'e';
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else if (P_ISLEAF(opaque))
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stat->type = 'l';
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else if (P_ISROOT(opaque))
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stat->type = 'r';
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else
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stat->type = 'i';
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/* btpage opaque data */
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stat->btpo_prev = opaque->btpo_prev;
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stat->btpo_next = opaque->btpo_next;
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stat->btpo.level = opaque->btpo.level;
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stat->btpo_flags = opaque->btpo_flags;
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stat->btpo_cycleid = opaque->btpo_cycleid;
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/* count live and dead tuples, and free space */
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for (off = FirstOffsetNumber; off <= maxoff; off++)
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{
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IndexTuple itup;
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ItemId id = PageGetItemId(page, off);
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itup = (IndexTuple) PageGetItem(page, id);
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item_size += IndexTupleSize(itup);
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if (!ItemIdDeleted(id))
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stat->live_items++;
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else
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stat->dead_items++;
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}
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stat->free_size = PageGetFreeSpace(page);
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if ((stat->live_items + stat->dead_items) > 0)
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stat->avg_item_size = item_size / (stat->live_items + stat->dead_items);
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else
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stat->avg_item_size = 0;
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}
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/* -----------------------------------------------
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* bt_page()
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*
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* Usage: SELECT * FROM bt_page('t1_pkey', 0);
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* -----------------------------------------------
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*/
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Datum
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bt_page_stats(PG_FUNCTION_ARGS)
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{
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text *relname = PG_GETARG_TEXT_P(0);
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uint32 blkno = PG_GETARG_UINT32(1);
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Buffer buffer;
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Relation rel;
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RangeVar *relrv;
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Datum result;
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relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
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rel = relation_openrv(relrv, AccessShareLock);
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CHECK_RELATION_BLOCK_RANGE(rel, blkno);
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buffer = ReadBuffer(rel, blkno);
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if (!IS_INDEX(rel) || !IS_BTREE(rel))
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elog(ERROR, "bt_page_stats() can be used only on b-tree index.");
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if (blkno == 0)
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elog(ERROR, "Block 0 is a meta page.");
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{
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HeapTuple tuple;
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TupleDesc tupleDesc;
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int j;
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char *values[BTPAGESTATS_NCOLUMNS];
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BTPageStat stat;
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/* keep compiler quiet */
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stat.btpo_prev = stat.btpo_next = InvalidBlockNumber;
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stat.btpo_flags = stat.free_size = stat.avg_item_size = 0;
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GetBTPageStatistics(blkno, buffer, &stat);
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tupleDesc = RelationNameGetTupleDesc(BTPAGESTATS_TYPE);
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j = 0;
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.blkno);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%c", stat.type);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.live_items);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.dead_items);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.avg_item_size);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.page_size);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.free_size);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.btpo_prev);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.btpo_next);
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values[j] = palloc(32);
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if (stat.type == 'd')
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snprintf(values[j++], 32, "%d", stat.btpo.xact);
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else
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snprintf(values[j++], 32, "%d", stat.btpo.level);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.btpo_flags);
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tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc),
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values);
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result = TupleGetDatum(TupleDescGetSlot(tupleDesc), tuple);
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}
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ReleaseBuffer(buffer);
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relation_close(rel, AccessShareLock);
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PG_RETURN_DATUM(result);
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}
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/*-------------------------------------------------------
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* bt_page_items()
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*
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* Get IndexTupleData set in a leaf page
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*
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* Usage: SELECT * FROM bt_page_items('t1_pkey', 0);
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*-------------------------------------------------------
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*/
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/* ---------------------------------------------------
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* data structure for SRF to hold a scan information
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* ---------------------------------------------------
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*/
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struct user_args
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{
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TupleDesc tupd;
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Relation rel;
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Buffer buffer;
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Page page;
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uint16 offset;
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};
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Datum
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bt_page_items(PG_FUNCTION_ARGS)
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{
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text *relname = PG_GETARG_TEXT_P(0);
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uint32 blkno = PG_GETARG_UINT32(1);
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RangeVar *relrv;
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Datum result;
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char *values[BTPAGEITEMS_NCOLUMNS];
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BTPageOpaque opaque;
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HeapTuple tuple;
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ItemId id;
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FuncCallContext *fctx;
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MemoryContext mctx;
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struct user_args *uargs = NULL;
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if (blkno == 0)
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elog(ERROR, "Block 0 is a meta page.");
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if (SRF_IS_FIRSTCALL())
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{
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fctx = SRF_FIRSTCALL_INIT();
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mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
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uargs = palloc(sizeof(struct user_args));
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uargs->tupd = RelationNameGetTupleDesc(BTPAGEITEMS_TYPE);
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uargs->offset = FirstOffsetNumber;
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relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
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uargs->rel = relation_openrv(relrv, AccessShareLock);
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CHECK_RELATION_BLOCK_RANGE(uargs->rel, blkno);
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uargs->buffer = ReadBuffer(uargs->rel, blkno);
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if (!IS_INDEX(uargs->rel) || !IS_BTREE(uargs->rel))
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elog(ERROR, "bt_page_items() can be used only on b-tree index.");
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uargs->page = BufferGetPage(uargs->buffer);
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opaque = (BTPageOpaque) PageGetSpecialPointer(uargs->page);
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if (P_ISDELETED(opaque))
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elog(NOTICE, "bt_page_items(): this page is deleted.");
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fctx->max_calls = PageGetMaxOffsetNumber(uargs->page);
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fctx->user_fctx = uargs;
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MemoryContextSwitchTo(mctx);
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}
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fctx = SRF_PERCALL_SETUP();
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uargs = fctx->user_fctx;
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if (fctx->call_cntr < fctx->max_calls)
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{
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IndexTuple itup;
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id = PageGetItemId(uargs->page, uargs->offset);
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if (!ItemIdIsValid(id))
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elog(ERROR, "Invalid ItemId.");
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itup = (IndexTuple) PageGetItem(uargs->page, id);
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{
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int j = 0;
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BlockNumber blkno = BlockIdGetBlockNumber(&(itup->t_tid.ip_blkid));
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", uargs->offset);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "(%u,%u)", blkno, itup->t_tid.ip_posid);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", (int) IndexTupleSize(itup));
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%c", IndexTupleHasNulls(itup) ? 't' : 'f');
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%c", IndexTupleHasVarwidths(itup) ? 't' : 'f');
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{
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int off;
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char *dump;
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char *ptr = (char *) itup + IndexInfoFindDataOffset(itup->t_info);
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dump = palloc(IndexTupleSize(itup) * 3);
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memset(dump, 0, IndexTupleSize(itup) * 3);
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for (off = 0;
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off < IndexTupleSize(itup) - IndexInfoFindDataOffset(itup->t_info);
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off++)
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{
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if (dump[0] == '\0')
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sprintf(dump, "%02x", *(ptr + off) & 0xff);
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else
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{
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char buf[4];
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sprintf(buf, " %02x", *(ptr + off) & 0xff);
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strcat(dump, buf);
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}
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}
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values[j] = dump;
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}
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tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(uargs->tupd), values);
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result = TupleGetDatum(TupleDescGetSlot(uargs->tupd), tuple);
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}
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uargs->offset = uargs->offset + 1;
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SRF_RETURN_NEXT(fctx, result);
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}
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else
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{
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ReleaseBuffer(uargs->buffer);
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relation_close(uargs->rel, AccessShareLock);
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SRF_RETURN_DONE(fctx);
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}
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}
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/* ------------------------------------------------
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* bt_metap()
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*
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* Get a btree meta-page information
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*
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* Usage: SELECT * FROM bt_metap('t1_pkey')
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* ------------------------------------------------
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*/
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Datum
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bt_metap(PG_FUNCTION_ARGS)
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{
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text *relname = PG_GETARG_TEXT_P(0);
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Buffer buffer;
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Relation rel;
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RangeVar *relrv;
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Datum result;
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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, "bt_metap() can be used only on b-tree index.");
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buffer = ReadBuffer(rel, 0);
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{
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BTMetaPageData *metad;
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TupleDesc tupleDesc;
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int j;
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char *values[BTMETAP_NCOLUMNS];
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HeapTuple tuple;
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Page page = BufferGetPage(buffer);
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metad = BTPageGetMeta(page);
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tupleDesc = RelationNameGetTupleDesc(BTMETAP_TYPE);
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j = 0;
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", metad->btm_magic);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", metad->btm_version);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", metad->btm_root);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", metad->btm_level);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", metad->btm_fastroot);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", metad->btm_fastlevel);
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tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc),
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values);
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result = TupleGetDatum(TupleDescGetSlot(tupleDesc), tuple);
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}
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ReleaseBuffer(buffer);
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relation_close(rel, AccessShareLock);
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PG_RETURN_DATUM(result);
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}
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