database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-12-02 23:42:46 +03:00
Code Activity

Revert no-op changes to BufferGetPage()

Browse Source 
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

16
src/backend/access/transam/generic_xlog.c
View File

@@ -298,9 +298,7 @@ GenericXLogRegisterBuffer(GenericXLogState *state, Buffer buffer, int flags)
/* Empty slot, so use it (there cannot be a match later) */
page->buffer = buffer;
page->flags = flags;
memcpy(page->image,
BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST),
BLCKSZ);
memcpy(page->image, BufferGetPage(buffer), BLCKSZ);
return (Page) page->image;
}
else if (page->buffer == buffer)
@@ -345,8 +343,7 @@ GenericXLogFinish(GenericXLogState *state)
if (BufferIsInvalid(pageData->buffer))
continue;
page = BufferGetPage(pageData->buffer, NULL, NULL,
BGP_NO_SNAPSHOT_TEST);
page = BufferGetPage(pageData->buffer);
pageHeader = (PageHeader) pageData->image;
if (pageData->flags & GENERIC_XLOG_FULL_IMAGE)
@@ -399,8 +396,7 @@ GenericXLogFinish(GenericXLogState *state)
if (BufferIsInvalid(pageData->buffer))
continue;
PageSetLSN(BufferGetPage(pageData->buffer, NULL, NULL,
BGP_NO_SNAPSHOT_TEST), lsn);
PageSetLSN(BufferGetPage(pageData->buffer), lsn);
MarkBufferDirty(pageData->buffer);
}
END_CRIT_SECTION();
@@ -415,8 +411,7 @@ GenericXLogFinish(GenericXLogState *state)
if (BufferIsInvalid(pageData->buffer))
continue;
memcpy(BufferGetPage(pageData->buffer, NULL, NULL,
BGP_NO_SNAPSHOT_TEST),
memcpy(BufferGetPage(pageData->buffer),
pageData->image,
BLCKSZ);
/* We don't worry about zeroing the "hole" in this case */
@@ -502,8 +497,7 @@ generic_redo(XLogReaderState *record)
char *blockDelta;
Size blockDeltaSize;
page = BufferGetPage(buffers[block_id], NULL, NULL,
BGP_NO_SNAPSHOT_TEST);
page = BufferGetPage(buffers[block_id]);
blockDelta = XLogRecGetBlockData(record, block_id, &blockDeltaSize);
applyPageRedo(page, blockDelta, blockDeltaSize);

8
src/backend/access/transam/xloginsert.c
View File

@@ -228,7 +228,7 @@ XLogRegisterBuffer(uint8 block_id, Buffer buffer, uint8 flags)
regbuf = &registered_buffers[block_id];
BufferGetTag(buffer, &regbuf->rnode, &regbuf->forkno, &regbuf->block);
regbuf->page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
regbuf->page = BufferGetPage(buffer);
regbuf->flags = flags;
regbuf->rdata_tail = (XLogRecData *) &regbuf->rdata_head;
regbuf->rdata_len = 0;
@@ -825,7 +825,7 @@ XLogCheckBufferNeedsBackup(Buffer buffer)
GetFullPageWriteInfo(&RedoRecPtr, &doPageWrites);
page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
page = BufferGetPage(buffer);
if (doPageWrites && PageGetLSN(page) <= RedoRecPtr)
return true; /* buffer requires backup */
@@ -896,7 +896,7 @@ XLogSaveBufferForHint(Buffer buffer, bool buffer_std)
if (buffer_std)
{
/* Assume we can omit data between pd_lower and pd_upper */
Page page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
Page page = BufferGetPage(buffer);
uint16 lower = ((PageHeader) page)->pd_lower;
uint16 upper = ((PageHeader) page)->pd_upper;
@@ -973,7 +973,7 @@ log_newpage(RelFileNode *rnode, ForkNumber forkNum, BlockNumber blkno,
XLogRecPtr
log_newpage_buffer(Buffer buffer, bool page_std)
{
Page page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
Page page = BufferGetPage(buffer);
RelFileNode rnode;
ForkNumber forkNum;
BlockNumber blkno;

8
src/backend/access/transam/xlogutils.c
View File

@@ -358,7 +358,7 @@ XLogReadBufferForRedoExtended(XLogReaderState *record,
{
*buf = XLogReadBufferExtended(rnode, forknum, blkno,
get_cleanup_lock ? RBM_ZERO_AND_CLEANUP_LOCK : RBM_ZERO_AND_LOCK);
page = BufferGetPage(*buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
page = BufferGetPage(*buf);
if (!RestoreBlockImage(record, block_id, page))
elog(ERROR, "failed to restore block image");
@@ -396,8 +396,7 @@ XLogReadBufferForRedoExtended(XLogReaderState *record,
else
LockBuffer(*buf, BUFFER_LOCK_EXCLUSIVE);
}
if (lsn <= PageGetLSN(BufferGetPage(*buf, NULL, NULL,
BGP_NO_SNAPSHOT_TEST)))
if (lsn <= PageGetLSN(BufferGetPage(*buf)))
return BLK_DONE;
else
return BLK_NEEDS_REDO;
@@ -503,8 +502,7 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
if (mode == RBM_NORMAL)
{
/* check that page has been initialized */
Page page = BufferGetPage(buffer, NULL, NULL,
BGP_NO_SNAPSHOT_TEST);
Page page = (Page) BufferGetPage(buffer);
/*
* We assume that PageIsNew is safe without a lock. During recovery,