Re: CopyReadAttributesCSV optimization - Mailing list pgsql-patches

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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