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Fix bug in GenericXLogFinish(). 

Mark the buffers dirty before writing WAL.

Discussion: https://postgr.es/m/25104133-7df8-cae3-b9a2-1c0aaa1c094a@iki.fi
Reviewed-by: Heikki Linnakangas
Backpatch-through: 11
This commit is contained in:
Jeff Davis 2023-10-10 11:01:13 -07:00
parent 694d6700e8
commit 04f0baa858
1 changed files with 26 additions and 30 deletions
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56
src/backend/access/transam/generic_xlog.c
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@ -342,6 +342,10 @@ GenericXLogFinish(GenericXLogState *state)
START_CRIT_SECTION();
/*
* Compute deltas if necessary, write changes to buffers, mark
* buffers dirty, and register changes.
*/
for (i = 0; i < MAX_GENERIC_XLOG_PAGES; i++)
{
PageData *pageData = &state->pages[i];
@ -354,41 +358,34 @@ GenericXLogFinish(GenericXLogState *state)
page = BufferGetPage(pageData->buffer);
pageHeader = (PageHeader) pageData->image;
/*
* Compute delta while we still have both the unmodified page and
* the new image. Not needed if we are logging the full image.
*/
if (!(pageData->flags & GENERIC_XLOG_FULL_IMAGE))
computeDelta(pageData, page, (Page) pageData->image);
/*
* Apply the image, being careful to zero the "hole" between
* pd_lower and pd_upper in order to avoid divergence between
* actual page state and what replay would produce.
*/
memcpy(page, pageData->image, pageHeader->pd_lower);
memset(page + pageHeader->pd_lower, 0,
pageHeader->pd_upper - pageHeader->pd_lower);
memcpy(page + pageHeader->pd_upper,
pageData->image + pageHeader->pd_upper,
BLCKSZ - pageHeader->pd_upper);
MarkBufferDirty(pageData->buffer);
if (pageData->flags & GENERIC_XLOG_FULL_IMAGE)
{
/*
* A full-page image does not require us to supply any xlog
* data. Just apply the image, being careful to zero the
* "hole" between pd_lower and pd_upper in order to avoid
* divergence between actual page state and what replay would
* produce.
*/
memcpy(page, pageData->image, pageHeader->pd_lower);
memset(page + pageHeader->pd_lower, 0,
pageHeader->pd_upper - pageHeader->pd_lower);
memcpy(page + pageHeader->pd_upper,
pageData->image + pageHeader->pd_upper,
BLCKSZ - pageHeader->pd_upper);
XLogRegisterBuffer(i, pageData->buffer,
REGBUF_FORCE_IMAGE | REGBUF_STANDARD);
}
else
{
/*
* In normal mode, calculate delta and write it as xlog data
* associated with this page.
*/
computeDelta(pageData, page, (Page) pageData->image);
/* Apply the image, with zeroed "hole" as above */
memcpy(page, pageData->image, pageHeader->pd_lower);
memset(page + pageHeader->pd_lower, 0,
pageHeader->pd_upper - pageHeader->pd_lower);
memcpy(page + pageHeader->pd_upper,
pageData->image + pageHeader->pd_upper,
BLCKSZ - pageHeader->pd_upper);
XLogRegisterBuffer(i, pageData->buffer, REGBUF_STANDARD);
XLogRegisterBufData(i, pageData->delta, pageData->deltaLen);
}
@ -397,7 +394,7 @@ GenericXLogFinish(GenericXLogState *state)
/* Insert xlog record */
lsn = XLogInsert(RM_GENERIC_ID, 0);
/* Set LSN and mark buffers dirty */
/* Set LSN */
for (i = 0; i < MAX_GENERIC_XLOG_PAGES; i++)
{
PageData *pageData = &state->pages[i];
@ -405,7 +402,6 @@ GenericXLogFinish(GenericXLogState *state)
if (BufferIsInvalid(pageData->buffer))
continue;
PageSetLSN(BufferGetPage(pageData->buffer), lsn);
MarkBufferDirty(pageData->buffer);
}
END_CRIT_SECTION();
}