Hi hackers,

The SLRU managed by predicate.c can wrap around and overwrite data if
you have more than 1 billion active XIDs.  That's because when SSI was
implemented, slru.c was limited to four digit segment names, which
implied a page limit that wasn't enough for pg_serial to have space
for every possible XID.  We should probably rip that code out, because
SLRUs now support five digit segment names.  Something like the
attached.  I'll post a test script to demonstrate correct wraparound
behaviour around in time for one of the later CFs.

Thomas Munro

Attachment: ssi-slru-wraparound-v1.patch
Description: Binary data

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