Re: VACUUM FULL doesn't reduce table size - Mailing list pgsql-general

From Vick Khera
Subject Re: VACUUM FULL doesn't reduce table size
Date
Msg-id CALd+dcfDtydsO7fdR_so0ZhRFhSeQ0vg3NCkp+CUpYemhfWyAQ@mail.gmail.com
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In response to VACUUM FULL doesn't reduce table size  (pinker <pinker@onet.eu>)
Responses Re: VACUUM FULL doesn't reduce table size  (David G Johnston <david.g.johnston@gmail.com>)
Re: VACUUM FULL doesn't reduce table size  (pinker <pinker@onet.eu>)
List pgsql-general

On Fri, Mar 6, 2015 at 5:59 AM, pinker <pinker@onet.eu> wrote:
I have deleted a large number of records from my_table, which originally had
288 MB. Then I ran vacuum full to make the table size smaller. After this
operation size of the table remains the same, despite of the fact that table

If your remaining records were in say, block 2 and block 10000, then the blocks in between won't be returned to the system.

You could achieve your "fix" by running cluster on the table, which will rewrite the table in-place.  There are also scripts out there that do in-place compaction by running targeted updates and vacuum commands to get the empty pages at the end of the files truncated off the file.

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