I see a lot of suggestions to increase maintenance work mem if running
pg_restore. This is to help with the index creation and initial sort from
what I understand. A few tests I ran does show this helps.
Does anyone know if there is a way to only "temporarily" set this setting?
I have some DBs that are bloated and I have a script to run off hours (I
don't like working late). This uses pg_dump and pg_restore to recover the
disk space. I found that this is usually faster than 'vacuum full', and is
useful in some cases.

I know I can set this for my current session dynamically "set
maintenance_work_mem = xxxxx", but it seems that the only way I can do this
for pg_restore is to update the configuration, reload and then change it
back when the script completes and reload again.

Thanks

Deron

Deron escribió:
> I see a lot of suggestions to increase maintenance work mem if running
> pg_restore. This is to help with the index creation and initial sort from
> what I understand. A few tests I ran does show this helps.
> Does anyone know if there is a way to only "temporarily" set this setting?
> I have some DBs that are bloated and I have a script to run off hours (I
> don't like working late). This uses pg_dump and pg_restore to recover the
> disk space. I found that this is usually faster than 'vacuum full', and is
> useful in some cases.

You can specify it via PGOPTIONS:

$ PGOPTIONS='-c maintenance_work_mem=1GB' psql
Welcome to psql 8.2.5, the PostgreSQL interactive terminal.

Type: \copyright for distribution terms
\h for help with SQL commands
\? for help with psql commands
\g or terminate with semicolon to execute query
\q to quit

alvherre=# show maintenance_work_mem ;
maintenance_work_mem
----------------------
1GB
(1 row)

alvherre=# \q

$ psql
Welcome to psql 8.2.5, the PostgreSQL interactive terminal.

Type: \copyright for distribution terms
\h for help with SQL commands
\? for help with psql commands
\g or terminate with semicolon to execute query
\q to quit

alvherre=# show maintenance_work_mem ;
maintenance_work_mem
----------------------
16MB
(1 row)



--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support

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TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match

On Dec 18, 2007 2:30 PM, Deron <fecastle@gmail.com> wrote:
> I see a lot of suggestions to increase maintenance work mem if running
> pg_restore. This is to help with the index creation and initial sort from
> what I understand. A few tests I ran does show this helps.
> Does anyone know if there is a way to only "temporarily" set this setting?
> I have some DBs that are bloated and I have a script to run off hours (I
> don't like working late). This uses pg_dump and pg_restore to recover the
> disk space. I found that this is usually faster than 'vacuum full', and is
> useful in some cases.
>
> I know I can set this for my current session dynamically "set
> maintenance_work_mem = xxxxx", but it seems that the only way I can do this
> for pg_restore is to update the configuration, reload and then change it
> back when the script completes and reload again.

If you use psql to restore, you can just add the set
maintenance_work_mem = xxx at the top of the file.

Also you can do it by creating a "special" superuser and altering that
user to inherit this new setting:

create user bubba superuser;
alter user bubba set maintenance_work_mem TO 512000;

then just connect as that user to run your restores or what not. You
can also set it for a non-super user, or a database as well.

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Deron <fecastle@gmail.com> writes:
> Does anyone know if there is a way to only "temporarily" set this setting?

Aside from the specific answers already given, the general answer is to
read
http://www.postgresql.org/docs/8.2/s...g-setting.html
which enumerates all (most?) of the many ways you can set configuration
parameters.

regards, tom lane

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TIP 2: Don't 'kill -9' the postmaster

Thanks for this and the other suggestions. This is exactly what I was
looking for.

Deron



On 12/18/07, Alvaro Herrera <alvherre@commandprompt.com> wrote:
>
> Deron escribió:
> > I see a lot of suggestions to increase maintenance work mem if running
> > pg_restore. This is to help with the index creation and initial sort
> from
> > what I understand. A few tests I ran does show this helps.
> > Does anyone know if there is a way to only "temporarily" set this
> setting?
> > I have some DBs that are bloated and I have a script to run off hours (I
> > don't like working late). This uses pg_dump and pg_restore to recover
> the
> > disk space. I found that this is usually faster than 'vacuum full', and
> is
> > useful in some cases.
>
> You can specify it via PGOPTIONS:
>
> $ PGOPTIONS='-c maintenance_work_mem=1GB' psql
> Welcome to psql 8.2.5, the PostgreSQL interactive terminal.
>
> Type: \copyright for distribution terms
> \h for help with SQL commands
> \? for help with psql commands
> \g or terminate with semicolon to execute query
> \q to quit
>
> alvherre=# show maintenance_work_mem ;
> maintenance_work_mem
> ----------------------
> 1GB
> (1 row)
>
> alvherre=# \q
>
> $ psql
> Welcome to psql 8.2.5, the PostgreSQL interactive terminal.
>
> Type: \copyright for distribution terms
> \h for help with SQL commands
> \? for help with psql commands
> \g or terminate with semicolon to execute query
> \q to quit
>
> alvherre=# show maintenance_work_mem ;
> maintenance_work_mem
> ----------------------
> 16MB
> (1 row)
>
>
>
> --
> Alvaro Herrera
> http://www.CommandPrompt.com/
> PostgreSQL Replication, Consulting, Custom Development, 24x7 support
>