Re: patch: fix performance problems with repated decomprimation of varlena values in plpgsql
Andrew Dunstan <andrew@dunslane.net>
From: Andrew Dunstan <andrew@dunslane.net>
To: Pavel Stehule <pavel.stehule@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>
Date: 2010-11-22T12:55:54Z
Lists: pgsql-hackers
On 11/22/2010 07:46 AM, Pavel Stehule wrote: > 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 > Since you haven't told us exactly how you tested this it's hard to gauge the test results. cheers andrew