Re: Performance of COPY for Archive operations

[Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>]

Simon Riggs wrote:
> 
> I've spent a while working with PITR functionality on the Win32 port.
> 
> I noticed that *it works*, which is always great, but using a COPY command
> the archival operation was significantly slower than the writing of the
> xlogs themselves.
> 
> At one point, I got to being more than 10 xlog files behind with the list
> growing steadily, and took a while to clear the logjam when my test
> workloads completed. Not much point having archiving thats actually slower
> than the writing of xlog....

Why was it slow?  'cp' was slower than the WAL writes?  Seems strange to
me.   Do we have some sleep loop in there that is causing us to read
that directory too slowly?  I didn't think so.

> IIRC the COPY command isn't the best thing to use for bulk-copying on
> Windows, but I can't remember what is better. Anybody?

COPY is the fastest way to get data in and out of PostgreSQL.

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