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Let caller of PageIsVerified() control ignore_checksum_failure

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For AIO the completion of a read into shared buffers (i.e. verifying the page
including the checksum, updating the BufferDesc to reflect the IO) can happen
in a different backend than the backend that started the IO. As
ignore_checksum_failure can differ between backends, we need to allow the
caller of PageIsVerified() control whether to ignore checksum failures.

The commit leaves a gap in the PIV_* values, as an upcoming commit, which
depends on this commit, will add PIV_LOG_LOG, which better fits just after
PIV_LOG_WARNING.

Reviewed-by: Noah Misch <noah@leadboat.com>
Discussion: https://postgr.es/m/20250329212929.a6.nmisch@google.com
This commit is contained in:
Andres Freund
2025-03-30 16:10:51 -04:00
parent b96d3c3897
commit d445990adc
4 changed files with 17 additions and 5 deletions
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7
src/backend/catalog/storage.c
View File

@ -508,6 +508,7 @@ RelationCopyStorage(SMgrRelation src, SMgrRelation dst,
for (blkno = 0; blkno < nblocks; blkno++)
{
BulkWriteBuffer buf;
int piv_flags;
bool checksum_failure;
bool verified;
@ -517,9 +518,11 @@ RelationCopyStorage(SMgrRelation src, SMgrRelation dst,
buf = smgr_bulk_get_buf(bulkstate);
smgrread(src, forkNum, blkno, (Page) buf);
verified = PageIsVerified((Page) buf, blkno, PIV_LOG_WARNING,
piv_flags = PIV_LOG_WARNING;
if (ignore_checksum_failure)
piv_flags |= PIV_IGNORE_CHECKSUM_FAILURE;
verified = PageIsVerified((Page) buf, blkno, piv_flags,
&checksum_failure);
if (checksum_failure)
{
RelFileLocatorBackend rloc = src->smgr_rlocator;

6
src/backend/storage/buffer/bufmgr.c
View File

@ -1569,6 +1569,7 @@ WaitReadBuffers(ReadBuffersOperation *operation)
{
BufferDesc *bufHdr;
Block bufBlock;
int piv_flags;
bool verified;
bool checksum_failure;
@ -1584,8 +1585,11 @@ WaitReadBuffers(ReadBuffersOperation *operation)
}
/* check for garbage data */
piv_flags = PIV_LOG_WARNING;
if (ignore_checksum_failure)
piv_flags |= PIV_IGNORE_CHECKSUM_FAILURE;
verified = PageIsVerified((Page) bufBlock, io_first_block + j,
PIV_LOG_WARNING, &checksum_failure);
piv_flags, &checksum_failure);
if (checksum_failure)
{
RelFileLocatorBackend rloc = operation->smgr->smgr_rlocator;

8
src/backend/storage/page/bufpage.c
View File

@ -81,10 +81,14 @@ PageInit(Page page, Size pageSize, Size specialSize)
* If flag PIV_LOG_WARNING is set, a WARNING is logged in the event of
* a checksum failure.
*
* If flag PIV_IGNORE_CHECKSUM_FAILURE is set, checksum failures will cause a
* message about the failure to be emitted, but will not cause
* PageIsVerified() to return false.
*
* To allow the caller to report statistics about checksum failures,
* *checksum_failure_p can be passed in. Note that there may be checksum
* failures even if this function returns true, due to
* ignore_checksum_failure.
* IGNORE_CHECKSUM_FAILURE.
*/
bool
PageIsVerified(PageData *page, BlockNumber blkno, int flags, bool *checksum_failure_p)
@ -150,7 +154,7 @@ PageIsVerified(PageData *page, BlockNumber blkno, int flags, bool *checksum_fail
errmsg("page verification failed, calculated checksum %u but expected %u",
checksum, p->pd_checksum)));
if (header_sane && ignore_checksum_failure)
if (header_sane && (flags & PIV_IGNORE_CHECKSUM_FAILURE))
return true;
}

1
src/include/storage/bufpage.h
View File

@ -467,6 +467,7 @@ do { \
/* flags for PageIsVerified() */
#define PIV_LOG_WARNING (1 << 0)
#define PIV_IGNORE_CHECKSUM_FAILURE (1 << 2)
#define PageAddItem(page, item, size, offsetNumber, overwrite, is_heap) \
PageAddItemExtended(page, item, size, offsetNumber, \