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提交 dcd40753 编写于 作者: T Teodor Sigaev
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Fix using too many LWLocks bug, reported by Craig Ringer 

<craig@postnewspapers.com.au>.
It was my mistake, I missed limitation of number of held locks, now GIN doesn't
use continiuous locks, but still hold buffers pinned to prevent interference
with vacuum's deletion algorithm.
上级 cebc3c42
隐藏空白更改
内联 并排
Showing with 167 addition and 213 deletion
src/backend/access/gin/ginget.c
浏览文件 @ dcd40753
......@@ -8,7 +8,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/gin/ginget.c,v 1.10 2008/01/01 19:45:46 momjian Exp $
* $PostgreSQL: pgsql/src/backend/access/gin/ginget.c,v 1.10.2.1 2008/04/22 17:54:19 teodor Exp $
*-------------------------------------------------------------------------
*/
......@@ -27,58 +27,16 @@ findItemInPage(Page page, ItemPointer item, OffsetNumber *off)
/* page was deleted by concurrent vacuum */
return false;
if (*off > maxoff || *off == InvalidOffsetNumber)
res = -1;
else
res = compareItemPointers(item, (ItemPointer) GinDataPageGetItem(page, *off));
/*
* scan page to find equal or first greater value
*/
if (res == 0)
for (*off = FirstOffsetNumber; *off <= maxoff; (*off)++)
{
/* page isn't changed */
return true;
}
else if (res > 0)
{
/*
* some items was added before our position, look further to find it
* or first greater
*/
(*off)++;
for (; *off <= maxoff; (*off)++)
{
res = compareItemPointers(item, (ItemPointer) GinDataPageGetItem(page, *off));
if (res == 0)
return true;
if (res < 0)
{
(*off)--;
return true;
}
}
}
else
{
/*
* some items was deleted before our position, look from begining to
* find it or first greater
*/
for (*off = FirstOffsetNumber; *off <= maxoff; (*off)++)
{
res = compareItemPointers(item, (ItemPointer) GinDataPageGetItem(page, *off));
if (res == 0)
return true;
res = compareItemPointers(item, (ItemPointer) GinDataPageGetItem(page, *off));
if (res < 0)
{
(*off)--;
return true;
}
}
if (res <= 0)
return true;
}
return false;
......@@ -89,119 +47,87 @@ findItemInPage(Page page, ItemPointer item, OffsetNumber *off)
* Stop* functions unlock buffer (but don't release!)
*/
static void
startScanEntry(Relation index, GinState *ginstate, GinScanEntry entry, bool firstCall)
startScanEntry(Relation index, GinState *ginstate, GinScanEntry entry)
{
GinBtreeData btreeEntry;
GinBtreeStack *stackEntry;
Page page;
bool needUnlock = TRUE;
if (entry->master != NULL)
{
entry->isFinished = entry->master->isFinished;
return;
}
if (firstCall)
/*
* we should find entry, and begin scan of posting tree
* or just store posting list in memory
*/
prepareEntryScan(&btreeEntry, index, entry->entry, ginstate);
btreeEntry.searchMode = TRUE;
stackEntry = ginFindLeafPage(&btreeEntry, NULL);
page = BufferGetPage(stackEntry->buffer);
entry->isFinished = TRUE;
entry->buffer = InvalidBuffer;
entry->offset = InvalidOffsetNumber;
entry->list = NULL;
entry->nlist = 0;
entry->reduceResult = FALSE;
entry->predictNumberResult = 0;
if (btreeEntry.findItem(&btreeEntry, stackEntry))
{
/*
* at first call we should find entry, and begin scan of posting tree
* or just store posting list in memory
*/
GinBtreeData btreeEntry;
GinBtreeStack *stackEntry;
Page page;
bool needUnlock = TRUE;
prepareEntryScan(&btreeEntry, index, entry->entry, ginstate);
btreeEntry.searchMode = TRUE;
stackEntry = ginFindLeafPage(&btreeEntry, NULL);
page = BufferGetPage(stackEntry->buffer);
entry->isFinished = TRUE;
entry->buffer = InvalidBuffer;
entry->offset = InvalidOffsetNumber;
entry->list = NULL;
entry->nlist = 0;
entry->reduceResult = FALSE;
entry->predictNumberResult = 0;
if (btreeEntry.findItem(&btreeEntry, stackEntry))
{
IndexTuple itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, stackEntry->off));
if (GinIsPostingTree(itup))
{
BlockNumber rootPostingTree = GinGetPostingTree(itup);
GinPostingTreeScan *gdi;
Page page;
LockBuffer(stackEntry->buffer, GIN_UNLOCK);
needUnlock = FALSE;
gdi = prepareScanPostingTree(index, rootPostingTree, TRUE);
entry->buffer = scanBeginPostingTree(gdi);
IncrBufferRefCount(entry->buffer);
page = BufferGetPage(entry->buffer);
entry->predictNumberResult = gdi->stack->predictNumber * GinPageGetOpaque(page)->maxoff;
IndexTuple itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, stackEntry->off));
freeGinBtreeStack(gdi->stack);
pfree(gdi);
entry->isFinished = FALSE;
}
else if (GinGetNPosting(itup) > 0)
{
entry->nlist = GinGetNPosting(itup);
entry->list = (ItemPointerData *) palloc(sizeof(ItemPointerData) * entry->nlist);
memcpy(entry->list, GinGetPosting(itup), sizeof(ItemPointerData) * entry->nlist);
entry->isFinished = FALSE;
}
}
if (GinIsPostingTree(itup))
{
BlockNumber rootPostingTree = GinGetPostingTree(itup);
GinPostingTreeScan *gdi;
Page page;
if (needUnlock)
LockBuffer(stackEntry->buffer, GIN_UNLOCK);
freeGinBtreeStack(stackEntry);
}
else if (entry->buffer != InvalidBuffer)
{
/* we should find place where we was stopped */
BlockNumber blkno;
Page page;
LockBuffer(entry->buffer, GIN_SHARE);
needUnlock = FALSE;
gdi = prepareScanPostingTree(index, rootPostingTree, TRUE);
if (!ItemPointerIsValid(&entry->curItem))
/* start position */
return;
Assert(entry->offset != InvalidOffsetNumber);
entry->buffer = scanBeginPostingTree(gdi);
/*
* We keep buffer pinned because we need to prevent deletition
* page during scan. See GIN's vacuum implementation. RefCount
* is increased to keep buffer pinned after freeGinBtreeStack() call.
*/
IncrBufferRefCount(entry->buffer);
page = BufferGetPage(entry->buffer);
page = BufferGetPage(entry->buffer);
entry->predictNumberResult = gdi->stack->predictNumber * GinPageGetOpaque(page)->maxoff;
/* try to find curItem in current buffer */
if (findItemInPage(page, &entry->curItem, &entry->offset))
return;
/*
* Keep page content in memory to prevent durable page locking
*/
entry->list = (ItemPointerData *) palloc( BLCKSZ );
entry->nlist = GinPageGetOpaque(page)->maxoff;
memcpy( entry->list, GinDataPageGetItem(page, FirstOffsetNumber),
GinPageGetOpaque(page)->maxoff * sizeof(ItemPointerData) );
/* walk to right */
while ((blkno = GinPageGetOpaque(page)->rightlink) != InvalidBlockNumber)
{
LockBuffer(entry->buffer, GIN_UNLOCK);
entry->buffer = ReleaseAndReadBuffer(entry->buffer, index, blkno);
LockBuffer(entry->buffer, GIN_SHARE);
page = BufferGetPage(entry->buffer);
entry->offset = InvalidOffsetNumber;
if (findItemInPage(page, &entry->curItem, &entry->offset))
return;
freeGinBtreeStack(gdi->stack);
pfree(gdi);
entry->isFinished = FALSE;
}
else if (GinGetNPosting(itup) > 0)
{
entry->nlist = GinGetNPosting(itup);
entry->list = (ItemPointerData *) palloc(sizeof(ItemPointerData) * entry->nlist);
memcpy(entry->list, GinGetPosting(itup), sizeof(ItemPointerData) * entry->nlist);
entry->isFinished = FALSE;
}
/*
* curItem and any greated items was deleted by concurrent vacuum, so
* we finished scan with currrent entry
*/
}
}
static void
stopScanEntry(GinScanEntry entry)
{
if (entry->buffer != InvalidBuffer)
LockBuffer(entry->buffer, GIN_UNLOCK);
if (needUnlock)
LockBuffer(stackEntry->buffer, GIN_UNLOCK);
freeGinBtreeStack(stackEntry);
}
static void
......@@ -209,47 +135,38 @@ startScanKey(Relation index, GinState *ginstate, GinScanKey key)
{
uint32 i;
if (!key->firstCall)
return;
for (i = 0; i < key->nentries; i++)
startScanEntry(index, ginstate, key->scanEntry + i, key->firstCall);
startScanEntry(index, ginstate, key->scanEntry + i);
if (key->firstCall)
{
memset(key->entryRes, TRUE, sizeof(bool) * key->nentries);
key->isFinished = FALSE;
key->firstCall = FALSE;
memset(key->entryRes, TRUE, sizeof(bool) * key->nentries);
key->isFinished = FALSE;
key->firstCall = FALSE;
if (GinFuzzySearchLimit > 0)
{
/*
* If all of keys more than threshold we will try to reduce
* result, we hope (and only hope, for intersection operation of
* array our supposition isn't true), that total result will not
* more than minimal predictNumberResult.
*/
if (GinFuzzySearchLimit > 0)
{
/*
* If all of keys more than threshold we will try to reduce
* result, we hope (and only hope, for intersection operation of
* array our supposition isn't true), that total result will not
* more than minimal predictNumberResult.
*/
for (i = 0; i < key->nentries; i++)
if (key->scanEntry[i].predictNumberResult <= key->nentries * GinFuzzySearchLimit)
return;
for (i = 0; i < key->nentries; i++)
if (key->scanEntry[i].predictNumberResult <= key->nentries * GinFuzzySearchLimit)
return;
for (i = 0; i < key->nentries; i++)
if (key->scanEntry[i].predictNumberResult > key->nentries * GinFuzzySearchLimit)
{
key->scanEntry[i].predictNumberResult /= key->nentries;
key->scanEntry[i].reduceResult = TRUE;
}
}
for (i = 0; i < key->nentries; i++)
if (key->scanEntry[i].predictNumberResult > key->nentries * GinFuzzySearchLimit)
{
key->scanEntry[i].predictNumberResult /= key->nentries;
key->scanEntry[i].reduceResult = TRUE;
}
}
}
static void
stopScanKey(GinScanKey key)
{
uint32 i;
for (i = 0; i < key->nentries; i++)
stopScanEntry(key->scanEntry + i);
}
static void
startScan(IndexScanDesc scan)
{
......@@ -260,44 +177,82 @@ startScan(IndexScanDesc scan)
startScanKey(scan->indexRelation, &so->ginstate, so->keys + i);
}
static void
stopScan(IndexScanDesc scan)
{
uint32 i;
GinScanOpaque so = (GinScanOpaque) scan->opaque;
for (i = 0; i < so->nkeys; i++)
stopScanKey(so->keys + i);
}
/*
* Gets next ItemPointer from PostingTree. Note, that we copy
* page into GinScanEntry->list array and unlock page, but keep it pinned
* to prevent interference with vacuum
*/
static void
entryGetNextItem(Relation index, GinScanEntry entry)
{
Page page = BufferGetPage(entry->buffer);
Page page;
BlockNumber blkno;
entry->offset++;
if (entry->offset <= GinPageGetOpaque(page)->maxoff && GinPageGetOpaque(page)->maxoff >= FirstOffsetNumber)
for(;;)
{
entry->curItem = *(ItemPointerData *) GinDataPageGetItem(page, entry->offset);
}
else
{
BlockNumber blkno = GinPageGetOpaque(page)->rightlink;
entry->offset++;
LockBuffer(entry->buffer, GIN_UNLOCK);
if (blkno == InvalidBlockNumber)
if (entry->offset <= entry->nlist)
{
ReleaseBuffer(entry->buffer);
entry->buffer = InvalidBuffer;
entry->isFinished = TRUE;
entry->curItem = entry->list[entry->offset - 1];
return;
}
else
LockBuffer(entry->buffer, GIN_SHARE);
page = BufferGetPage(entry->buffer);
for(;;)
{
/*
* It's needed to go by right link. During that we should refind
* first ItemPointer greater that stored
*/
blkno = GinPageGetOpaque(page)->rightlink;
LockBuffer(entry->buffer, GIN_UNLOCK);
if (blkno == InvalidBlockNumber)
{
ReleaseBuffer(entry->buffer);
ItemPointerSet(&entry->curItem, InvalidBlockNumber, InvalidOffsetNumber);
entry->buffer = InvalidBuffer;
entry->isFinished = TRUE;
return;
}
entry->buffer = ReleaseAndReadBuffer(entry->buffer, index, blkno);
LockBuffer(entry->buffer, GIN_SHARE);
page = BufferGetPage(entry->buffer);
entry->offset = InvalidOffsetNumber;
entryGetNextItem(index, entry);
if (!ItemPointerIsValid(&entry->curItem) || findItemInPage(page, &entry->curItem, &entry->offset))
{
/*
* Found position equal to or greater than stored
*/
entry->nlist = GinPageGetOpaque(page)->maxoff;
memcpy( entry->list, GinDataPageGetItem(page, FirstOffsetNumber),
GinPageGetOpaque(page)->maxoff * sizeof(ItemPointerData) );
LockBuffer(entry->buffer, GIN_UNLOCK);
if ( !ItemPointerIsValid(&entry->curItem) ||
compareItemPointers( &entry->curItem, entry->list + entry->offset - 1 ) == 0 )
{
/*
* First pages are deleted or empty, or we found exact position,
* so break inner loop and continue outer one.
*/
break;
}
/*
* Find greater than entry->curItem position, store it.
*/
entry->curItem = entry->list[entry->offset - 1];
return;
}
}
}
}
......@@ -317,7 +272,7 @@ entryGetItem(Relation index, GinScanEntry entry)
entry->isFinished = entry->master->isFinished;
entry->curItem = entry->master->curItem;
}
else if (entry->list)
else if (!BufferIsValid(entry->buffer))
{
entry->offset++;
if (entry->offset <= entry->nlist)
......@@ -501,8 +456,6 @@ gingetmulti(PG_FUNCTION_ARGS)
break;
} while (*returned_tids < max_tids);
stopScan(scan);
PG_RETURN_BOOL(*returned_tids == max_tids);
}
......@@ -524,7 +477,6 @@ gingettuple(PG_FUNCTION_ARGS)
startScan(scan);
res = scanGetItem(scan, &scan->xs_ctup.t_self);
stopScan(scan);
PG_RETURN_BOOL(res);
}
src/include/access/gin.h
浏览文件 @ dcd40753
......@@ -4,7 +4,7 @@
*
* Copyright (c) 2006-2008, PostgreSQL Global Development Group
*
* $PostgreSQL: pgsql/src/include/access/gin.h,v 1.16 2008/01/01 19:45:56 momjian Exp $
* $PostgreSQL: pgsql/src/include/access/gin.h,v 1.16.2.1 2008/04/22 17:54:19 teodor Exp $
*--------------------------------------------------------------------------
*/
......@@ -356,14 +356,16 @@ typedef struct GinScanEntryData
/* entry, got from extractQueryFn */
Datum entry;
/* current ItemPointer to heap, its offset in buffer and buffer */
ItemPointerData curItem;
OffsetNumber offset;
/* Current page in posting tree */
Buffer buffer;
/* in case of Posing list */
/* current ItemPointer to heap */
ItemPointerData curItem;
/* used for Posting list and one page in Posting tree */
ItemPointerData *list;
uint32 nlist;
uint32 nlist;
OffsetNumber offset;
bool isFinished;
bool reduceResult;
......
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