204 lines
4.5 KiB
C
204 lines
4.5 KiB
C
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/*-------------------------------------------------------------------------
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*
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* ginutil.c
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* utilities routines for the postgres inverted index access method.
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*
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*
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* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/access/gin/ginutil.c,v 1.1 2006/05/02 11:28:54 teodor Exp $
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "access/genam.h"
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#include "access/gin.h"
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#include "access/heapam.h"
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#include "catalog/index.h"
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#include "miscadmin.h"
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#include "storage/freespace.h"
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void
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initGinState( GinState *state, Relation index ) {
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if ( index->rd_att->natts != 1 )
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elog(ERROR, "numberOfAttributes %d != 1",
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index->rd_att->natts);
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state->tupdesc = index->rd_att;
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fmgr_info_copy(&(state->compareFn),
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index_getprocinfo(index, 1, GIN_COMPARE_PROC),
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CurrentMemoryContext);
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fmgr_info_copy(&(state->extractValueFn),
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index_getprocinfo(index, 1, GIN_EXTRACTVALUE_PROC),
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CurrentMemoryContext);
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fmgr_info_copy(&(state->extractQueryFn),
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index_getprocinfo(index, 1, GIN_EXTRACTQUERY_PROC),
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CurrentMemoryContext);
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fmgr_info_copy(&(state->consistentFn),
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index_getprocinfo(index, 1, GIN_CONSISTENT_PROC),
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CurrentMemoryContext);
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}
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/*
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* Allocate a new page (either by recycling, or by extending the index file)
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* The returned buffer is already pinned and exclusive-locked
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* Caller is responsible for initializing the page by calling GinInitBuffer
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*/
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Buffer
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GinNewBuffer(Relation index) {
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Buffer buffer;
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bool needLock;
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/* First, try to get a page from FSM */
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for(;;) {
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BlockNumber blkno = GetFreeIndexPage(&index->rd_node);
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if (blkno == InvalidBlockNumber)
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break;
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buffer = ReadBuffer(index, blkno);
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/*
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* We have to guard against the possibility that someone else already
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* recycled this page; the buffer may be locked if so.
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*/
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if (ConditionalLockBuffer(buffer)) {
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Page page = BufferGetPage(buffer);
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if (PageIsNew(page))
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return buffer; /* OK to use, if never initialized */
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if (GinPageIsDeleted(page))
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return buffer; /* OK to use */
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LockBuffer(buffer, GIN_UNLOCK);
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}
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/* Can't use it, so release buffer and try again */
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ReleaseBuffer(buffer);
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}
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/* Must extend the file */
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needLock = !RELATION_IS_LOCAL(index);
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if (needLock)
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LockRelationForExtension(index, ExclusiveLock);
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buffer = ReadBuffer(index, P_NEW);
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LockBuffer(buffer, GIN_EXCLUSIVE);
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if (needLock)
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UnlockRelationForExtension(index, ExclusiveLock);
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return buffer;
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}
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void
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GinInitPage(Page page, uint32 f, Size pageSize) {
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GinPageOpaque opaque;
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PageInit(page, pageSize, sizeof(GinPageOpaqueData));
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opaque = GinPageGetOpaque(page);
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memset( opaque, 0, sizeof(GinPageOpaqueData) );
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opaque->flags = f;
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opaque->rightlink = InvalidBlockNumber;
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}
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void
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GinInitBuffer(Buffer b, uint32 f) {
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GinInitPage( BufferGetPage(b), f, BufferGetPageSize(b) );
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}
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int
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compareEntries(GinState *ginstate, Datum a, Datum b) {
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return DatumGetInt32(
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FunctionCall2(
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&ginstate->compareFn,
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a, b
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)
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);
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}
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static FmgrInfo* cmpDatumPtr=NULL;
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static bool needUnique = FALSE;
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static int
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cmpEntries(const void * a, const void * b) {
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int res = DatumGetInt32(
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FunctionCall2(
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cmpDatumPtr,
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*(Datum*)a,
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*(Datum*)b
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)
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);
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if ( res == 0 )
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needUnique = TRUE;
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return res;
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}
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Datum*
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extractEntriesS(GinState *ginstate, Datum value, uint32 *nentries) {
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Datum *entries;
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entries = (Datum*)DatumGetPointer(
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FunctionCall2(
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&ginstate->extractValueFn,
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value,
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PointerGetDatum( nentries )
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)
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);
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if ( entries == NULL )
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*nentries = 0;
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if ( *nentries > 1 ) {
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cmpDatumPtr = &ginstate->compareFn;
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needUnique = FALSE;
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qsort(entries, *nentries, sizeof(Datum), cmpEntries);
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}
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return entries;
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}
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Datum*
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extractEntriesSU(GinState *ginstate, Datum value, uint32 *nentries) {
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Datum *entries = extractEntriesS(ginstate, value, nentries);
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if ( *nentries>1 && needUnique ) {
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Datum *ptr, *res;
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ptr = res = entries;
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while( ptr - entries < *nentries ) {
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if ( compareEntries(ginstate, *ptr, *res ) != 0 )
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*(++res) = *ptr++;
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else
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ptr++;
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}
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*nentries = res + 1 - entries;
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}
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return entries;
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}
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/*
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* It's analog of PageGetTempPage(), but copies whole page
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*/
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Page
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GinPageGetCopyPage( Page page ) {
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Size pageSize = PageGetPageSize( page );
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Page tmppage;
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tmppage=(Page)palloc( pageSize );
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memcpy( tmppage, page, pageSize );
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return tmppage;
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}
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