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* Show_database_bloat reliability? [was: Re: REINDEX not working for wastedspace]
@ 2011-09-21 12:43 Guillaume Cottenceau <gc@mnc.ch>
0 siblings, 1 reply; 2+ messages in thread
From: Guillaume Cottenceau @ 2011-09-21 12:43 UTC (permalink / raw)
To: pgsql-performance
AI Rumman <rummandba 'at' gmail.com> writes:
> Using the query http://wiki.postgresql.org/wiki/Show_database_bloat, I got the
Is this stuff to show database bloat reliable? After a VACUUM
FULL of the table reported as the top responsible of bloat,
performing the same request again still gives the same result
(still that table is the top responsible of bloat):
current_database | schemaname | tablename | tbloat | wastedbytes | iname | ibloat | wastedibytes
------------------+------------+-----------------------------------------+--------+-------------+------------------------------------------------------+--------+--------------
test | public | requests | 1.1 | 14565376 | requests_pkey | 0.4 | 0
test | public | requests | 1.1 | 14565376 | idx_whatever | 0.8 | 0
test | public | requests | 1.1 | 14565376 | idx_whatever2 | 0.6 | 0
...
A few investigations show that when tbloat is close to 1.0 then
it seems not reliable, otherwise it seems useful.
pg 8.4.7
--
Guillaume Cottenceau
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: Show_database_bloat reliability? [was: Re: REINDEX not working for wastedspace]
@ 2011-09-21 16:12 Greg Smith <greg@2ndQuadrant.com>
parent: Guillaume Cottenceau <gc@mnc.ch>
0 siblings, 0 replies; 2+ messages in thread
From: Greg Smith @ 2011-09-21 16:12 UTC (permalink / raw)
To: pgsql-performance
On 09/21/2011 08:43 AM, Guillaume Cottenceau wrote:
> AI Rumman<rummandba 'at' gmail.com> writes:
>
>
>> Using the query http://wiki.postgresql.org/wiki/Show_database_bloat, I got the
>>
> Is this stuff to show database bloat reliable?
Only in that increase and decreases of the number reported can be useful
for determining if bloat is likely increasing or decreasing--which is
the purpose of that query. The value returned is a rough estimate, and
should not be considered useful as any sort of absolute measurement.
--
Greg Smith 2ndQuadrant US greg@2ndQuadrant.com Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us
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2011-09-21 12:43 Show_database_bloat reliability? [was: Re: REINDEX not working for wastedspace] Guillaume Cottenceau <gc@mnc.ch>
2011-09-21 16:12 ` Greg Smith <greg@2ndQuadrant.com>
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