Thread: BUG #16012: vacuum full, something weird

BUG #16012: vacuum full, something weird

From
PG Bug reporting form
Date:
The following bug has been logged on the website:

Bug reference:      16012
Logged by:          Richard Klaumann
Email address:      richard.klaumann@gmail.com
PostgreSQL version: 9.5.3
Operating system:   Centos 7.x
Description:

Hello,
First sorry for my english.
Today we store our byteas in tables. We are moving these files to
storages.
During the process we set the bytea column to null and execute vacum full
(in the table itself and in the table pg_catalog.pg_largeobject).
In some tables we continue with pg_total_relation_size> 24GB (practically
the initial size). Data in the toast table.
If I run a new vacuum full on the main table, the space is freed.

Can someone help me?

Sorry if it's not the correct list.

Thankful,
Richard


Re: BUG #16012: vacuum full, something weird

From
Jeff Janes
Date:


On Wed, Sep 18, 2019 at 9:25 AM PG Bug reporting form <noreply@postgresql.org> wrote:
The following bug has been logged on the website:

Bug reference:      16012
Logged by:          Richard Klaumann
Email address:      richard.klaumann@gmail.com
PostgreSQL version: 9.5.3
Operating system:   Centos 7.x
Description:       

Hello,
First sorry for my english.
Today we store our byteas in tables. We are moving these files to
storages.
During the process we set the bytea column to null and execute vacum full
(in the table itself and in the table pg_catalog.pg_largeobject).

pg_largeobject has nothing to do with data stored in bytea columns.
 
In some tables we continue with pg_total_relation_size> 24GB (practically
the initial size). Data in the toast table.
If I run a new vacuum full on the main table, the space is freed.

Data can only be freed once every snapshot that could possibly be interested in it has closed.

So if you have any long-running statements, or long-open transactions with isolation level above read-committed, it would inhibit the removal of the data by vacuum full (or any other level of vacuum)

Cheers,

Jeff