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Revert no-op changes to BufferGetPage()

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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
This commit is contained in:
Kevin Grittner
2016-04-20 08:31:19 -05:00
parent 4db0d2d2fe
commit a343e223a5
65 changed files with 550 additions and 736 deletions
Download Patch File Download Diff File Expand all files Collapse all files

71
src/backend/access/gin/ginbtree.c
View File

@ -36,7 +36,7 @@ ginTraverseLock(Buffer buffer, bool searchMode)
int access = GIN_SHARE;
LockBuffer(buffer, GIN_SHARE);
page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
page = BufferGetPage(buffer);
if (GinPageIsLeaf(page))
{
if (searchMode == FALSE)
@ -89,8 +89,8 @@ ginFindLeafPage(GinBtree btree, bool searchMode, Snapshot snapshot)
stack->off = InvalidOffsetNumber;
page = BufferGetPage(stack->buffer, snapshot, btree->index,
BGP_TEST_FOR_OLD_SNAPSHOT);
page = BufferGetPage(stack->buffer);
TestForOldSnapshot(snapshot, btree->index, page);
access = ginTraverseLock(stack->buffer, searchMode);
@ -116,8 +116,8 @@ ginFindLeafPage(GinBtree btree, bool searchMode, Snapshot snapshot)
stack->buffer = ginStepRight(stack->buffer, btree->index, access);
stack->blkno = rightlink;
page = BufferGetPage(stack->buffer, snapshot, btree->index,
BGP_TEST_FOR_OLD_SNAPSHOT);
page = BufferGetPage(stack->buffer);
TestForOldSnapshot(snapshot, btree->index, page);
if (!searchMode && GinPageIsIncompleteSplit(page))
ginFinishSplit(btree, stack, false, NULL);
@ -163,7 +163,7 @@ Buffer
ginStepRight(Buffer buffer, Relation index, int lockmode)
{
Buffer nextbuffer;
Page page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
Page page = BufferGetPage(buffer);
bool isLeaf = GinPageIsLeaf(page);
bool isData = GinPageIsData(page);
BlockNumber blkno = GinPageGetOpaque(page)->rightlink;
@ -173,7 +173,7 @@ ginStepRight(Buffer buffer, Relation index, int lockmode)
UnlockReleaseBuffer(buffer);
/* Sanity check that the page we stepped to is of similar kind. */
page = BufferGetPage(nextbuffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
page = BufferGetPage(nextbuffer);
if (isLeaf != GinPageIsLeaf(page) || isData != GinPageIsData(page))
elog(ERROR, "right sibling of GIN page is of different type");
@ -245,7 +245,7 @@ ginFindParents(GinBtree btree, GinBtreeStack *stack)
for (;;)
{
LockBuffer(buffer, GIN_EXCLUSIVE);
page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
page = BufferGetPage(buffer);
if (GinPageIsLeaf(page))
elog(ERROR, "Lost path");
@ -276,7 +276,7 @@ ginFindParents(GinBtree btree, GinBtreeStack *stack)
break;
}
buffer = ginStepRight(buffer, btree->index, GIN_EXCLUSIVE);
page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
page = BufferGetPage(buffer);
/* finish any incomplete splits, as above */
if (GinPageIsIncompleteSplit(page))
@ -327,8 +327,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
void *insertdata, BlockNumber updateblkno,
Buffer childbuf, GinStatsData *buildStats)
{
Page page = BufferGetPage(stack->buffer, NULL, NULL,
BGP_NO_SNAPSHOT_TEST);
Page page = BufferGetPage(stack->buffer);
GinPlaceToPageRC rc;
uint16 xlflags = 0;
Page childpage = NULL;
@ -347,7 +346,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
{
Assert(BufferIsValid(childbuf));
Assert(updateblkno != InvalidBlockNumber);
childpage = BufferGetPage(childbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
childpage = BufferGetPage(childbuf);
}
/*
@ -459,8 +458,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
data.flags = xlflags;
if (childbuf != InvalidBuffer)
{
Page childpage = BufferGetPage(childbuf, NULL, NULL,
BGP_NO_SNAPSHOT_TEST);
Page childpage = BufferGetPage(childbuf);
GinPageGetOpaque(childpage)->flags &= ~GIN_INCOMPLETE_SPLIT;
@ -542,21 +540,14 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
if (stack->parent == NULL)
{
MarkBufferDirty(lbuffer);
memcpy(BufferGetPage(stack->buffer, NULL, NULL,
BGP_NO_SNAPSHOT_TEST),
newrootpg, BLCKSZ);
memcpy(BufferGetPage(lbuffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST),
newlpage, BLCKSZ);
memcpy(BufferGetPage(rbuffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST),
newrpage, BLCKSZ);
memcpy(BufferGetPage(stack->buffer), newrootpg, BLCKSZ);
memcpy(BufferGetPage(lbuffer), newlpage, BLCKSZ);
memcpy(BufferGetPage(rbuffer), newrpage, BLCKSZ);
}
else
{
memcpy(BufferGetPage(stack->buffer, NULL, NULL,
BGP_NO_SNAPSHOT_TEST),
newlpage, BLCKSZ);
memcpy(BufferGetPage(rbuffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST),
newrpage, BLCKSZ);
memcpy(BufferGetPage(stack->buffer), newlpage, BLCKSZ);
memcpy(BufferGetPage(rbuffer), newrpage, BLCKSZ);
}
/* write WAL record */
@ -588,16 +579,10 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
XLogRegisterData((char *) &data, sizeof(ginxlogSplit));
recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_SPLIT);
PageSetLSN(BufferGetPage(stack->buffer, NULL, NULL,
BGP_NO_SNAPSHOT_TEST),
recptr);
PageSetLSN(BufferGetPage(rbuffer, NULL, NULL,
BGP_NO_SNAPSHOT_TEST),
recptr);
PageSetLSN(BufferGetPage(stack->buffer), recptr);
PageSetLSN(BufferGetPage(rbuffer), recptr);
if (stack->parent == NULL)
PageSetLSN(BufferGetPage(lbuffer, NULL, NULL,
BGP_NO_SNAPSHOT_TEST),
recptr);
PageSetLSN(BufferGetPage(lbuffer), recptr);
if (BufferIsValid(childbuf))
PageSetLSN(childpage, recptr);
}
@ -679,12 +664,11 @@ ginFinishSplit(GinBtree btree, GinBtreeStack *stack, bool freestack,
* page that has no downlink in the parent, and splitting it further
* would fail.
*/
if (GinPageIsIncompleteSplit(BufferGetPage(parent->buffer, NULL, NULL,
BGP_NO_SNAPSHOT_TEST)))
if (GinPageIsIncompleteSplit(BufferGetPage(parent->buffer)))
ginFinishSplit(btree, parent, false, buildStats);
/* move right if it's needed */
page = BufferGetPage(parent->buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
page = BufferGetPage(parent->buffer);
while ((parent->off = btree->findChildPtr(btree, page, stack->blkno, parent->off)) == InvalidOffsetNumber)
{
if (GinPageRightMost(page))
@ -702,17 +686,15 @@ ginFinishSplit(GinBtree btree, GinBtreeStack *stack, bool freestack,
parent->buffer = ginStepRight(parent->buffer, btree->index, GIN_EXCLUSIVE);
parent->blkno = BufferGetBlockNumber(parent->buffer);
page = BufferGetPage(parent->buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
page = BufferGetPage(parent->buffer);
if (GinPageIsIncompleteSplit(BufferGetPage(parent->buffer, NULL, NULL,
BGP_NO_SNAPSHOT_TEST)))
if (GinPageIsIncompleteSplit(BufferGetPage(parent->buffer)))
ginFinishSplit(btree, parent, false, buildStats);
}
/* insert the downlink */
insertdata = btree->prepareDownlink(btree, stack->buffer);
updateblkno = GinPageGetOpaque(BufferGetPage(stack->buffer, NULL, NULL,
BGP_NO_SNAPSHOT_TEST))->rightlink;
updateblkno = GinPageGetOpaque(BufferGetPage(stack->buffer))->rightlink;
done = ginPlaceToPage(btree, parent,
insertdata, updateblkno,
stack->buffer, buildStats);
@ -762,8 +744,7 @@ ginInsertValue(GinBtree btree, GinBtreeStack *stack, void *insertdata,
bool done;
/* If the leaf page was incompletely split, finish the split first */
if (GinPageIsIncompleteSplit(BufferGetPage(stack->buffer, NULL, NULL,
BGP_NO_SNAPSHOT_TEST)))
if (GinPageIsIncompleteSplit(BufferGetPage(stack->buffer)))
ginFinishSplit(btree, stack, false, buildStats);
done = ginPlaceToPage(btree, stack,