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Re: Zero dead tuples, when significant apparent bloat - Mailing list pgsql-general

From bricklen
Subject Re: Zero dead tuples, when significant apparent bloat
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Msg-id CAGrpgQ-m=HVB66fDynRWqKE5h4awPaJUT3srg3mQFG5LdWZgog@mail.gmail.com
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In response to Zero dead tuples, when significant apparent bloat  (John Melesky <john.melesky@rentrakmail.com>)
Responses Re: Zero dead tuples, when significant apparent bloat  (John Melesky <john.melesky@rentrakmail.com>)
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On Tue, Dec 10, 2013 at 5:05 PM, John Melesky <john.melesky@rentrakmail.com> wrote:
It seems clear that there were dead tuples, since the table size shrank to an eighth of its previous size. Why did analyze not pick that up?
Am I missing something?
This is a very large database, so we want to introspect against live/dead tuple percentage to minimize the tables we run a VACUUM FULL against.


If you willing to install the pgstattuple[1] extension, what does the output say? Note, there is some overhead on larger tables (disk I/O primarily)

select * from pgstattuple('your table');

Also, check the output from bloat query at https://wiki.postgresql.org/wiki/Show_database_bloat

[1]  http://www.postgresql.org/docs/current/static/pgstattuple.html

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