mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-09-10 21:03:21 +02:00
The reverted changes were intended to force a choice of whether any newly-added BufferGetPage() calls needed to be accompanied by a test of the snapshot age, to support the "snapshot too old" feature. Such an accompanying test is needed in about 7% of the cases, where the page is being used as part of a scan rather than positioning for other purposes (such as DML or vacuuming). The additional effort required for back-patching, and the doubt whether the intended benefit would really be there, have indicated it is best just to rely on developers to do the right thing based on comments and existing usage, as we do with many other conventions. This change should have little or no effect on generated executable code. Motivated by the back-patching pain of Tom Lane and Robert Haas
332 lines
8.5 KiB
C
332 lines
8.5 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* blinsert.c
|
|
* Bloom index build and insert functions.
|
|
*
|
|
* Copyright (c) 2016, PostgreSQL Global Development Group
|
|
*
|
|
* IDENTIFICATION
|
|
* contrib/bloom/blinsert.c
|
|
*
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
#include "postgres.h"
|
|
|
|
#include "access/genam.h"
|
|
#include "access/generic_xlog.h"
|
|
#include "catalog/index.h"
|
|
#include "miscadmin.h"
|
|
#include "storage/bufmgr.h"
|
|
#include "storage/indexfsm.h"
|
|
#include "utils/memutils.h"
|
|
#include "utils/rel.h"
|
|
|
|
#include "bloom.h"
|
|
|
|
PG_MODULE_MAGIC;
|
|
|
|
/*
|
|
* State of bloom index build. We accumulate one page data here before
|
|
* flushing it to buffer manager.
|
|
*/
|
|
typedef struct
|
|
{
|
|
BloomState blstate; /* bloom index state */
|
|
MemoryContext tmpCtx; /* temporary memory context reset after
|
|
* each tuple */
|
|
char data[BLCKSZ]; /* cached page */
|
|
int64 count; /* number of tuples in cached page */
|
|
} BloomBuildState;
|
|
|
|
/*
|
|
* Flush page cached in BloomBuildState.
|
|
*/
|
|
static void
|
|
flushCachedPage(Relation index, BloomBuildState *buildstate)
|
|
{
|
|
Page page;
|
|
Buffer buffer = BloomNewBuffer(index);
|
|
GenericXLogState *state;
|
|
|
|
state = GenericXLogStart(index);
|
|
page = GenericXLogRegisterBuffer(state, buffer, GENERIC_XLOG_FULL_IMAGE);
|
|
memcpy(page, buildstate->data, BLCKSZ);
|
|
GenericXLogFinish(state);
|
|
UnlockReleaseBuffer(buffer);
|
|
}
|
|
|
|
/*
|
|
* (Re)initialize cached page in BloomBuildState.
|
|
*/
|
|
static void
|
|
initCachedPage(BloomBuildState *buildstate)
|
|
{
|
|
memset(buildstate->data, 0, BLCKSZ);
|
|
BloomInitPage(buildstate->data, 0);
|
|
buildstate->count = 0;
|
|
}
|
|
|
|
/*
|
|
* Per-tuple callback from IndexBuildHeapScan.
|
|
*/
|
|
static void
|
|
bloomBuildCallback(Relation index, HeapTuple htup, Datum *values,
|
|
bool *isnull, bool tupleIsAlive, void *state)
|
|
{
|
|
BloomBuildState *buildstate = (BloomBuildState *) state;
|
|
MemoryContext oldCtx;
|
|
BloomTuple *itup;
|
|
|
|
oldCtx = MemoryContextSwitchTo(buildstate->tmpCtx);
|
|
|
|
itup = BloomFormTuple(&buildstate->blstate, &htup->t_self, values, isnull);
|
|
|
|
/* Try to add next item to cached page */
|
|
if (BloomPageAddItem(&buildstate->blstate, buildstate->data, itup))
|
|
{
|
|
/* Next item was added successfully */
|
|
buildstate->count++;
|
|
}
|
|
else
|
|
{
|
|
/* Cached page is full, flush it out and make a new one */
|
|
flushCachedPage(index, buildstate);
|
|
|
|
CHECK_FOR_INTERRUPTS();
|
|
|
|
initCachedPage(buildstate);
|
|
|
|
if (!BloomPageAddItem(&buildstate->blstate, buildstate->data, itup))
|
|
{
|
|
/* We shouldn't be here since we're inserting to the empty page */
|
|
elog(ERROR, "could not add new bloom tuple to empty page");
|
|
}
|
|
}
|
|
|
|
MemoryContextSwitchTo(oldCtx);
|
|
MemoryContextReset(buildstate->tmpCtx);
|
|
}
|
|
|
|
/*
|
|
* Build a new bloom index.
|
|
*/
|
|
IndexBuildResult *
|
|
blbuild(Relation heap, Relation index, IndexInfo *indexInfo)
|
|
{
|
|
IndexBuildResult *result;
|
|
double reltuples;
|
|
BloomBuildState buildstate;
|
|
|
|
if (RelationGetNumberOfBlocks(index) != 0)
|
|
elog(ERROR, "index \"%s\" already contains data",
|
|
RelationGetRelationName(index));
|
|
|
|
/* Initialize the meta page */
|
|
BloomInitMetapage(index);
|
|
|
|
/* Initialize the bloom build state */
|
|
memset(&buildstate, 0, sizeof(buildstate));
|
|
initBloomState(&buildstate.blstate, index);
|
|
buildstate.tmpCtx = AllocSetContextCreate(CurrentMemoryContext,
|
|
"Bloom build temporary context",
|
|
ALLOCSET_DEFAULT_MINSIZE,
|
|
ALLOCSET_DEFAULT_INITSIZE,
|
|
ALLOCSET_DEFAULT_MAXSIZE);
|
|
initCachedPage(&buildstate);
|
|
|
|
/* Do the heap scan */
|
|
reltuples = IndexBuildHeapScan(heap, index, indexInfo, true,
|
|
bloomBuildCallback, (void *) &buildstate);
|
|
|
|
/*
|
|
* There are could be some items in cached page. Flush this page
|
|
* if needed.
|
|
*/
|
|
if (buildstate.count > 0)
|
|
flushCachedPage(index, &buildstate);
|
|
|
|
MemoryContextDelete(buildstate.tmpCtx);
|
|
|
|
result = (IndexBuildResult *) palloc(sizeof(IndexBuildResult));
|
|
result->heap_tuples = result->index_tuples = reltuples;
|
|
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* Build an empty bloom index in the initialization fork.
|
|
*/
|
|
void
|
|
blbuildempty(Relation index)
|
|
{
|
|
if (RelationGetNumberOfBlocks(index) != 0)
|
|
elog(ERROR, "index \"%s\" already contains data",
|
|
RelationGetRelationName(index));
|
|
|
|
/* Initialize the meta page */
|
|
BloomInitMetapage(index);
|
|
}
|
|
|
|
/*
|
|
* Insert new tuple to the bloom index.
|
|
*/
|
|
bool
|
|
blinsert(Relation index, Datum *values, bool *isnull,
|
|
ItemPointer ht_ctid, Relation heapRel, IndexUniqueCheck checkUnique)
|
|
{
|
|
BloomState blstate;
|
|
BloomTuple *itup;
|
|
MemoryContext oldCtx;
|
|
MemoryContext insertCtx;
|
|
BloomMetaPageData *metaData;
|
|
Buffer buffer,
|
|
metaBuffer;
|
|
Page page,
|
|
metaPage;
|
|
BlockNumber blkno = InvalidBlockNumber;
|
|
OffsetNumber nStart;
|
|
GenericXLogState *state;
|
|
|
|
insertCtx = AllocSetContextCreate(CurrentMemoryContext,
|
|
"Bloom insert temporary context",
|
|
ALLOCSET_DEFAULT_MINSIZE,
|
|
ALLOCSET_DEFAULT_INITSIZE,
|
|
ALLOCSET_DEFAULT_MAXSIZE);
|
|
|
|
oldCtx = MemoryContextSwitchTo(insertCtx);
|
|
|
|
initBloomState(&blstate, index);
|
|
itup = BloomFormTuple(&blstate, ht_ctid, values, isnull);
|
|
|
|
/*
|
|
* At first, try to insert new tuple to the first page in notFullPage
|
|
* array. If successful, we don't need to modify the meta page.
|
|
*/
|
|
metaBuffer = ReadBuffer(index, BLOOM_METAPAGE_BLKNO);
|
|
LockBuffer(metaBuffer, BUFFER_LOCK_SHARE);
|
|
metaData = BloomPageGetMeta(BufferGetPage(metaBuffer));
|
|
|
|
if (metaData->nEnd > metaData->nStart)
|
|
{
|
|
Page page;
|
|
|
|
blkno = metaData->notFullPage[metaData->nStart];
|
|
Assert(blkno != InvalidBlockNumber);
|
|
|
|
/* Don't hold metabuffer lock while doing insert */
|
|
LockBuffer(metaBuffer, BUFFER_LOCK_UNLOCK);
|
|
|
|
buffer = ReadBuffer(index, blkno);
|
|
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
|
|
|
|
state = GenericXLogStart(index);
|
|
page = GenericXLogRegisterBuffer(state, buffer, 0);
|
|
|
|
if (BloomPageAddItem(&blstate, page, itup))
|
|
{
|
|
/* Success! Apply the change, clean up, and exit */
|
|
GenericXLogFinish(state);
|
|
UnlockReleaseBuffer(buffer);
|
|
ReleaseBuffer(metaBuffer);
|
|
MemoryContextSwitchTo(oldCtx);
|
|
MemoryContextDelete(insertCtx);
|
|
return false;
|
|
}
|
|
|
|
/* Didn't fit, must try other pages */
|
|
GenericXLogAbort(state);
|
|
UnlockReleaseBuffer(buffer);
|
|
}
|
|
else
|
|
{
|
|
/* No entries in notFullPage */
|
|
LockBuffer(metaBuffer, BUFFER_LOCK_UNLOCK);
|
|
}
|
|
|
|
/*
|
|
* Try other pages in notFullPage array. We will have to change nStart in
|
|
* metapage. Thus, grab exclusive lock on metapage.
|
|
*/
|
|
LockBuffer(metaBuffer, BUFFER_LOCK_EXCLUSIVE);
|
|
|
|
/* nStart might have changed while we didn't have lock */
|
|
nStart = metaData->nStart;
|
|
|
|
/* Skip first page if we already tried it above */
|
|
if (nStart < metaData->nEnd &&
|
|
blkno == metaData->notFullPage[nStart])
|
|
nStart++;
|
|
|
|
/*
|
|
* This loop iterates for each page we try from the notFullPage array, and
|
|
* will also initialize a GenericXLogState for the fallback case of having
|
|
* to allocate a new page.
|
|
*/
|
|
for (;;)
|
|
{
|
|
state = GenericXLogStart(index);
|
|
|
|
/* get modifiable copy of metapage */
|
|
metaPage = GenericXLogRegisterBuffer(state, metaBuffer, 0);
|
|
metaData = BloomPageGetMeta(metaPage);
|
|
|
|
if (nStart >= metaData->nEnd)
|
|
break; /* no more entries in notFullPage array */
|
|
|
|
blkno = metaData->notFullPage[nStart];
|
|
Assert(blkno != InvalidBlockNumber);
|
|
|
|
buffer = ReadBuffer(index, blkno);
|
|
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
|
|
page = GenericXLogRegisterBuffer(state, buffer, 0);
|
|
|
|
if (BloomPageAddItem(&blstate, page, itup))
|
|
{
|
|
/* Success! Apply the changes, clean up, and exit */
|
|
metaData->nStart = nStart;
|
|
GenericXLogFinish(state);
|
|
UnlockReleaseBuffer(buffer);
|
|
UnlockReleaseBuffer(metaBuffer);
|
|
MemoryContextSwitchTo(oldCtx);
|
|
MemoryContextDelete(insertCtx);
|
|
return false;
|
|
}
|
|
|
|
/* Didn't fit, must try other pages */
|
|
GenericXLogAbort(state);
|
|
UnlockReleaseBuffer(buffer);
|
|
nStart++;
|
|
}
|
|
|
|
/*
|
|
* Didn't find place to insert in notFullPage array. Allocate new page.
|
|
* (XXX is it good to do this while holding ex-lock on the metapage??)
|
|
*/
|
|
buffer = BloomNewBuffer(index);
|
|
|
|
page = GenericXLogRegisterBuffer(state, buffer, GENERIC_XLOG_FULL_IMAGE);
|
|
BloomInitPage(page, 0);
|
|
|
|
if (!BloomPageAddItem(&blstate, page, itup))
|
|
{
|
|
/* We shouldn't be here since we're inserting to an empty page */
|
|
elog(ERROR, "could not add new bloom tuple to empty page");
|
|
}
|
|
|
|
/* Reset notFullPage array to contain just this new page */
|
|
metaData->nStart = 0;
|
|
metaData->nEnd = 1;
|
|
metaData->notFullPage[0] = BufferGetBlockNumber(buffer);
|
|
|
|
/* Apply the changes, clean up, and exit */
|
|
GenericXLogFinish(state);
|
|
|
|
UnlockReleaseBuffer(buffer);
|
|
UnlockReleaseBuffer(metaBuffer);
|
|
|
|
MemoryContextSwitchTo(oldCtx);
|
|
MemoryContextDelete(insertCtx);
|
|
|
|
return false;
|
|
}
|