Ok. The reason I wanted to experiment with autovacuum disable for
'ddev2' database is that it is a mostly read-only database -- to support
querying from our web apps. I.e. there are only 1 or 2 small tables
ever updated all day on it, and only about 20 or so records total per
day (compared to 'ddev1' which has much more frequent activity). Also,
it's rebuilt periodically from the other db, so I had the idea that we
didn't need autovacuum running for 'ddev2'.
However, given that it is connected to the Postgres processes (launcher)
and I can't turn it off per database, it may not be worth the trouble to
configure this. I plan to experiment with other parameters as well, but
this is not critical at this time.
Thanks again.
--Jim Longwill :^)
On 10/29/2015 01:52 PM, Adrian Klaver wrote:
> On 10/29/2015 01:35 PM, Jim Longwill wrote:
>> Mr. Pierce, others,
>>
>> I spoke too soon on this. I'd like to do your alter database.. command
>> but it isn't working. I've tried:
>>
>> postgres=# ALTER DATABASE ddev2 SET autovacuum = off;
>>
>> both as 'postgres' user, and the ddev2 owner user (which has owner
>> privs), and I'm always getting this error:
>>
>> ERROR: parameter "autovacuum" cannot be changed now
>>
>> I've checked some documentation, tried many variations of the command,
>> (e.g. = off, false, 0, etc.) tried other variations as well. As you can
>> see in the above example, I'm connected to 'postgres' database. I tried
>> 'ddev2' also, etc. The above error is *always* the response.
>>
>> I'm certain that there are no other user sessions in this database.
>>
>> So.. what are the magic words? Thanks again!
>>
>
> Look for SEE in below:
>
> http://www.postgresql.org/docs/9.4/interactive/runtime-config-autovacuum.html
>
>
> "autovacuum (boolean)
>
> Controls whether the server should run the autovacuum launcher
> daemon. This is on by default; however, track_counts must also be
> enabled for autovacuum to work. SEE--> This parameter can only be set
> in the postgresql.conf file or on the server command line. <---SEE
>
> Note that even when this parameter is disabled, the system will
> launch autovacuum processes if necessary to prevent transaction ID
> wraparound. See Section 23.1.5 for more information.
> "
>