Re: RAM-only temporary tables - Mailing list pgsql-hackers

From Kevin Grittner
Subject Re: RAM-only temporary tables
Date
Msg-id 4912E4DC.EE98.0025.0@wicourts.gov
Whole thread Raw
In response to Re: RAM-only temporary tables  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: RAM-only temporary tables  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
>>> Tom Lane <tgl@sss.pgh.pa.us> wrote: 
> it's difficult to tell how much
> physical I/O results from the create or unlink syscalls.  It might
be
> interesting to make a test program that just creates 4000 files
We use xfs with noatime for our databases.
In a fresh subdirectory of such a mountpoint:
for ((i=0 ; i < 4000 ; ++i)) ; do touch $i ; done
causes 44,969 block writes
> and then
> removes them again, and see what sort of load you see from that.
rm *
causes 26,820 block writes
That would make the file creation and unlink just under half the load.
-Kevin


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