On Thu, Apr 29, 2021 at 9:31 AM Justin Pryzby <pry...@telsasoft.com> wrote: > > On Tue, Apr 27, 2021 at 03:22:25PM +0900, Michael Paquier wrote: > > Hi all, > > > And so, ALTER MATERIALIZED VIEW supports SET COMPRESSION but this is > > not mentioned in its docs: > > https://www.postgresql.org/docs/devel/sql-altermaterializedview.html > > > > psql could have tab completion support for that. > > Actually ALTER matview ALTER col has no tab completion at all, right ?
Right. > Good point. I started with this. > > diff --git a/doc/src/sgml/ref/alter_table.sgml > b/doc/src/sgml/ref/alter_table.sgml > index 39927be41e..8cceea41d0 100644 > --- a/doc/src/sgml/ref/alter_table.sgml > +++ b/doc/src/sgml/ref/alter_table.sgml > @@ -391,7 +391,21 @@ WITH ( MODULUS <replaceable > class="parameter">numeric_literal</replaceable>, REM > </term> > <listitem> > <para> > - This sets the compression method for a column. The supported > compression > + This sets the compression method to be used for data inserted into a > column. > + > + This does not cause the table to be rewritten, so existing data may > still > + be compressed with other compression methods. If the table is > rewritten with > + <command>VACUUM FULL</command> or <command>CLUSTER</command>, or > restored > + with <application>pg_restore</application>, then all tuples are > rewritten > + with the configured compression methods. > + > + Also, note that when data is inserted from another relation (for > example, > + by <command>INSERT ... SELECT</command>), tuples from the source data > are > + not necessarily detoasted, and any previously compressed data is > retained > + with its existing compression method, rather than recompressing with > the > + compression methods of the target columns. > + > + The supported compression > methods are <literal>pglz</literal> and <literal>lz4</literal>. > <literal>lz4</literal> is available only if > <literal>--with-lz4</literal> > was used when building <productname>PostgreSQL</productname>. Your documentation looks fine to me. -- Regards, Dilip Kumar EnterpriseDB: http://www.enterprisedb.com
