Re: CopyReadAttributesCSV optimization

Your patch has been added to the PostgreSQL unapplied patches list at:

http://momjian.postgresql.org/cgi-bin/pgpatches

It will be applied as soon as one of the PostgreSQL committers reviews
and approves it.

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Heikki Linnakangas wrote:
> Here's a patch to speed up CopyReadAttributesCSV. On the test case I've
> been playing with, loading the TPC-H partsupp table, about 20%
> CopyReadAttributesCSV (inlined into DoCopy, DoCopy itself is insignificant):
>
> samples % image name symbol name
> 8136 25.8360 postgres CopyReadLine
> 6350 20.1645 postgres DoCopy
> 2181 6.9258 postgres pg_verify_mbstr_len
> 2157 6.8496 reiserfs (no symbols)
> 1668 5.2968 libc-2.7.so memcpy
> 1142 3.6264 libc-2.7.so ____strtod_l_internal
> 951 3.0199 postgres heap_formtuple
> 904 2.8707 libc-2.7.so ____strtol_l_internal
> 619 1.9656 libc-2.7.so memset
> 442 1.4036 libc-2.7.so strlen
> 341 1.0828 postgres hash_any
> 329 1.0447 postgres pg_atoi
> 300 0.9527 postgres AllocSetAlloc
>
> With this patch, the usage of that function goes down to ~13%
>
> samples % image name symbol name
> 7191 28.7778 postgres CopyReadLine
> 3257 13.0343 postgres DoCopy
> 2127 8.5121 reiserfs (no symbols)
> 1914 7.6597 postgres pg_verify_mbstr_len
> 1413 5.6547 libc-2.7.so memcpy
> 920 3.6818 libc-2.7.so ____strtod_l_internal
> 784 3.1375 libc-2.7.so ____strtol_l_internal
> 745 2.9814 postgres heap_formtuple
> 508 2.0330 libc-2.7.so memset
> 398 1.5928 libc-2.7.so strlen
> 315 1.2606 postgres hash_any
> 255 1.0205 postgres AllocSetAlloc
>
> The trick is to split the loop in CopyReadAttributesCSV into two parts,
> inside quotes, and outside quotes, saving some instructions in both
> parts.
>
> Your mileage may vary, but I'm quite happy with this. I haven't tested
> it much yet, but I wouldn't expect it to be a loss in any interesting
> scenario. The code also doesn't look much worse after the patch, perhaps
> even better.
>
> --
> Heikki Linnakangas
> EnterpriseDB http://www.enterprisedb.com

>
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--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://postgres.enterprisedb.com

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