Re: [PATCHES] wal_checksum = on (default) | off - Mailing list pgsql-hackers

From Tom Lane
Subject Re: [PATCHES] wal_checksum = on (default) | off
Date
Msg-id 15436.1168007993@sss.pgh.pa.us
Whole thread Raw
In response to Re: [PATCHES] wal_checksum = on (default) | off  ("Zeugswetter Andreas ADI SD" <ZeugswetterA@spardat.at>)
Responses Re: [PATCHES] wal_checksum = on (default) | off
List pgsql-hackers
"Zeugswetter Andreas ADI SD" <ZeugswetterA@spardat.at> writes:
> Ok, so when you need CRC's on a replicate (but not on the master) you
> turn it
> off during standby replay, but turn it on when you start the replicate
> for normal operation.

Thought: even when it's off, the CRC had better be computed for
shutdown-checkpoint records.  Else there's no way to turn it on even
with a postmaster restart --- unless we accept the idea of poking a hole
in the normal mode.  (Which I still dislike, and even more so if the
special value is zero.  Almost any other value would be safer than zero.)

On the whole, though, I still don't want to put this in.  I don't think
Simon has thought it through sufficiently, and we haven't even seen any
demonstration of a big speedup.

(Another hole in the implementation as given: pg_resetxlog.)

            regards, tom lane

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