pgsql: Ignore nextOid when replaying an ONLINE checkpoint.

Ignore nextOid when replaying an ONLINE checkpoint.

The nextOid value is from the start of the checkpoint and may well be stale
compared to values from more recent XLOG_NEXTOID records. Previously, we
adopted it anyway, allowing the OID counter to go backwards during a crash.
While this should be harmless, it contributed to the severity of the bug
fixed in commit 0408e1ed5, by allowing duplicate TOAST OIDs to be assigned
immediately following a crash. Without this error, that issue would only
have arisen when TOAST objects just younger than a multiple of 2^32 OIDs
were deleted and then not vacuumed in time to avoid a conflict.

Pavan Deolasee

Discussion: /messages/by-id/CABOikdOgWT2hHkYG3Wwo2cyZJq2zfs1FH0FgX-=h4OLosXHf9w@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/d1e9079295e9e6fcab8f2ad9c69dd1be8e876d47

Modified Files
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src/backend/access/transam/xlog.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)