Jeff Davis wrote:
On Tue, 2007-07-03 at 12:33 -0400, Christopher Browne wrote:
I'll see about doing an experiment on this to see if, for the DELETE
case, it seems to actually help. It may be that the performance
effects are small to none, so that the added code complication isn't
worthwhile.
In a simple test I ran, DELETE of the entire 5M record table using
sequential scan was MUCH faster (9.41s) than 5M individual DELETE
statements in a single transaction (552.49s).
I have a test running here...
[EMAIL PROTECTED]:~/records/2007/2007-07-03> for i in *log; do
for> echo $i
for> echo "-------------------------------------------------------"
for> cat $i
for> echo "======================================================="
for> done
hundreds.log
-------------------------------------------------------
Started
Tue Jul 3 22:03:16 UTC 2007
=======================================================
onedelete.log
-------------------------------------------------------
Started
Tue Jul 3 21:57:04 UTC 2007
Started purging by onedelete
Tue Jul 3 21:58:41 UTC 2007
Completed deletions
Tue Jul 3 21:59:24 UTC 2007
=======================================================
thousands.log
-------------------------------------------------------
Started
Tue Jul 3 21:47:07 UTC 2007
Started purging by thousands
Tue Jul 3 21:47:22 UTC 2007
Completed deletions
Tue Jul 3 21:53:12 UTC 2007
=======================================================
My PC is evidently slower than yours; it took ~43s for the "one big delete"
Doing it in groups of 1K took 4:50 (e.g. - 4 minutes 50 seconds)
I'll be running against groups of 100 and against groups of 1 overnight;
presumably both will be worse than my other numbers. It'll be
interesting to see how much worse than 4:50 it gets...
_______________________________________________
Slony1-general mailing list
[email protected]
http://lists.slony.info/mailman/listinfo/slony1-general
