Re: changing MyDatabaseId - Mailing list pgsql-hackers

From Tom Lane
Subject Re: changing MyDatabaseId
Date
Msg-id 26563.1290007551@sss.pgh.pa.us
Whole thread Raw
In response to Re: changing MyDatabaseId  (Markus Wanner <markus@bluegap.ch>)
Responses Re: changing MyDatabaseId
List pgsql-hackers
Markus Wanner <markus@bluegap.ch> writes:
> On 11/17/2010 02:19 PM, Alvaro Herrera wrote:
>> Well, the autovacuum mechanism involves a lot of back-and-forth between
>> launcher and postmaster, which includes some signals, a fork() and
>> backend initialization.  The failure possibilities are endless.
>> 
>> Fork failure communication is similarly brittle.

> I certainly agree to that. However, a re-connecting mechanism wouldn't
> allow us to get rid of the existing avworker startup infrastructure
> entirely.

I'm afraid that any such change would trade a visible, safe failure
mechanism (no avworker) for invisible, impossible-to-debug data
corruption scenarios (due to failure to reset some bit of cached state).
It certainly won't give me any warm fuzzy feeling that I can trust
autovacuum.
        regards, tom lane


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