| From: | Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> |
|---|---|
| To: | PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Subject: | patch: fix performance problems with repated decomprimation of varlena values in plpgsql |
| Date: | 2010-11-22 12:46:51 |
| Message-ID: | AANLkTintO8HQST-D8_hE+pANpT+zqnavuHL2auFFD_OS@mail.gmail.com |
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| Lists: | pgsql-hackers |
Hello
this patch remove a multiple detoasting of varlena values in plpgsql.
It is usable mainly for iteration over longer array directly loaded
from relation.
It's doesn't have a impact on semantic or behave - it's just eliminate
some performance trap.
sample: table 10000 rows one column with array with 1000 string fields:
patched pl time: 6 sec
unpatched pl time: 170 sec
This doesn't change my opinion on FOR-IN-ARRAY cycle (is still
important for readability) - just remove one critical performance
issue
Regards
Pavel Stehule
| Attachment | Content-Type | Size |
|---|---|---|
| varlena_accelerator.diff | text/x-patch | 6.0 KB |
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