Re: WAL and commit_delay

* Bruce Momjian <pgman@candle.pha.pa.us> [010217 14:46]:
> > Right now the WAL preallocation code (XLogFileInit) is not good enough
> > because it does lseek to the 16MB position and then writes 1 byte there.
> > On an implementation that supports holes in files (which is most Unixen)
> > that doesn't cause physical allocation of the intervening space.  We'd
> > have to actually write zeroes into all 16MB to ensure the space is
> > allocated ... but that's just a couple more lines of code.
> 
> Are OS's smart enough to not allocate zero-written blocks?  Do we need
> to write non-zeros?
I don't believe so.  writing Zeros is valid.  
> 
> -- 
>   Bruce Momjian                        |  http://candle.pha.pa.us
>   pgman@candle.pha.pa.us               |  (610) 853-3000
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-- 
Larry Rosenman                     http://www.lerctr.org/~ler
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