Re: [HACKERS] The dangers of "-F" - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: [HACKERS] The dangers of "-F"
Date
Msg-id 199906241542.LAA17009@candle.pha.pa.us
Whole thread Raw
In response to Re: [HACKERS] The dangers of "-F"  (Zeugswetter Andreas IZ5 <Andreas.Zeugswetter@telecom.at>)
List pgsql-hackers
> 
> > For instance, if there are assumptions that all data blocks are
> > written before this fact is recorded in a log file, then
> > "write data blocks" "fsynch" "write log" "fsynch" doesn't break
> > that assumption, 
> > 
> Are we really doing a sync after the pg_log write ? While the sync
> after datablock write seems necessary to guarantee consistency,
> the sync after log write is actually not necessary to guarantee consistency.
> Would it be a first step, to special case the writing to pg_log, as
> to not sync (extra switch to backend) ? This would avoid the syncs
> for read only transactions, since they don't cause data block writes.

You are right.  We don't need a sync after the pg_log write.

--  Bruce Momjian                        |  http://www.op.net/~candle maillist@candle.pha.pa.us            |  (610)
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