Re: does refreshing materialized view make the database bloat? - Mailing list pgsql-general

From jian he
Subject Re: does refreshing materialized view make the database bloat?
Date
Msg-id CACJufxHkmQGpXajgWhETjDvk1hO6mUEJ1o4F151z7DnT3OOXAA@mail.gmail.com
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In response to Re: does refreshing materialized view make the database bloat?  ("David G. Johnston" <david.g.johnston@gmail.com>)
Responses Re: does refreshing materialized view make the database bloat?
List pgsql-general


On Sat, Jan 14, 2023 at 11:49 AM David G. Johnston <david.g.johnston@gmail.com> wrote:
On Friday, January 13, 2023, jian he <jian.universality@gmail.com> wrote:

Once we have the diff table, we perform set-based DELETE and INSERT
operations against the materialized view, and discard both temporary tables.

Here the temporary tables are "discard" meaning the temporary tables are deleted and the temporary tables' spaces are reclaimed immediately?
Or the temporary tables are deleted and the spaces will be reclaimed by another mechanism? 

simplify:does refreshing materialized view make the database bloat.


The materialized view itself bloats.  The temp tables are removed immediately (the “drop table” docs don’t say this explicitly though it the most logical behavior and implied by the fact it takes an access exclusive lock).

David J.


Hi,
why the materialized view itself bloats. If no refresh then no bloat right? If fresh then set based delete operation will make materialized view bloat?
I also found the same question online. https://dba.stackexchange.com/questions/219079/bloat-on-materialized-views Unfortunately nobody answered...




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