Re: Interpreting shared_buffers setting
Jerry Sievers writes: > Bob Jolliffe writes: > >> Excuse me if this is a silly question. I am trying to fiddle with >> shared_buffers setting on postgresql 10.6 on ubuntu 18.04 server. >> >> I have this at bottom of my config file: >> shared_buffers = 1GB >> >> Yet when I check the setting from pg_setting I see something quite different: >> >> postgres=# SELECT name, setting FROM pg_settings where name = >> 'shared_buffers'; >> name | setting >> +- >> shared_buffers | 131072 Ay! Pasted junk... Here's what I meant. meta_a:postgres# select setting from pg_settings where name='shared_buffers'; setting - 131072 (1 row) meta_a:postgres# show shared_buffers; shared_buffers 1GB (1 row) > > Why not use the show command which is good about output in human > terms... > > psql (11.1 (Ubuntu 11.1-1.pgdg16.04+1)) > Type "help" for help. > > meta_a:postgres# select name, setting from pg_settings where name = > 'shared_buffers'); > ERROR: syntax error at or near ")" > LINE 1: ...me, setting from pg_settings where name = 'shared_buffers'); > ^ > meta_a:postgres# > >> >> Is this a question of units? It looks like 128M. Note when I change >> the setting to 2GB in conf file I see 262144 from pg_setting. I am >> now unsure what the actual shared_buffers allocation is. I cant see >> anything in the docs which tells me how to interpret the integer. >> >> Any clarification welcome. >> >> Regards >> Bob >> >> -- Jerry Sievers Postgres DBA/Development Consulting e: postgres.consult...@comcast.net
Re: Interpreting shared_buffers setting
Bob Jolliffe writes: > Excuse me if this is a silly question. I am trying to fiddle with > shared_buffers setting on postgresql 10.6 on ubuntu 18.04 server. > > I have this at bottom of my config file: > shared_buffers = 1GB > > Yet when I check the setting from pg_setting I see something quite different: > > postgres=# SELECT name, setting FROM pg_settings where name = > 'shared_buffers'; > name | setting > +- > shared_buffers | 131072 Why not use the show command which is good about output in human terms... psql (11.1 (Ubuntu 11.1-1.pgdg16.04+1)) Type "help" for help. meta_a:postgres# select name, setting from pg_settings where name = 'shared_buffers'); ERROR: syntax error at or near ")" LINE 1: ...me, setting from pg_settings where name = 'shared_buffers'); ^ meta_a:postgres# > > Is this a question of units? It looks like 128M. Note when I change > the setting to 2GB in conf file I see 262144 from pg_setting. I am > now unsure what the actual shared_buffers allocation is. I cant see > anything in the docs which tells me how to interpret the integer. > > Any clarification welcome. > > Regards > Bob > > -- Jerry Sievers Postgres DBA/Development Consulting e: postgres.consult...@comcast.net
Re: Interpreting shared_buffers setting
Thank you Andrew and Thomas. All is now clear :-) On Tue, 29 Jan 2019 at 13:07, Andrew Gierth wrote: > > > "Bob" == Bob Jolliffe writes: > > Bob> Excuse me if this is a silly question. I am trying to fiddle with > Bob> shared_buffers setting on postgresql 10.6 on ubuntu 18.04 server. > > Bob> I have this at bottom of my config file: > Bob> shared_buffers = 1GB > > Bob> Yet when I check the setting from pg_setting I see something quite > Bob> different: > > Bob> postgres=# SELECT name, setting FROM pg_settings where name = > 'shared_buffers'; > Bob> name | setting > Bob> +- > Bob> shared_buffers | 131072 > > pg_settings can tell you more than you asked for: > > postgres=# select * from pg_settings where name='shared_buffers'; > -[ RECORD 1 ]---+- > name| shared_buffers > setting | 16384 > unit| 8kB > category| Resource Usage / Memory > short_desc | Sets the number of shared memory buffers used by the server. > extra_desc | > context | postmaster > vartype | integer > source | configuration file > min_val | 16 > max_val | 1073741823 > enumvals| > boot_val| 1024 > reset_val | 16384 > sourcefile | /home/andrew/work/pgsql/inst/9.5/data/postgresql.conf > sourceline | 113 > pending_restart | f > > notice that "unit 8kB" line; the displayed integer value is in units of > 8kB (which is the block size your server was compiled with, which you > can also see as the block_size parameter). > > -- > Andrew (irc:RhodiumToad)
Re: Interpreting shared_buffers setting
> "Bob" == Bob Jolliffe writes: Bob> Excuse me if this is a silly question. I am trying to fiddle with Bob> shared_buffers setting on postgresql 10.6 on ubuntu 18.04 server. Bob> I have this at bottom of my config file: Bob> shared_buffers = 1GB Bob> Yet when I check the setting from pg_setting I see something quite Bob> different: Bob> postgres=# SELECT name, setting FROM pg_settings where name = 'shared_buffers'; Bob> name | setting Bob> +- Bob> shared_buffers | 131072 pg_settings can tell you more than you asked for: postgres=# select * from pg_settings where name='shared_buffers'; -[ RECORD 1 ]---+- name| shared_buffers setting | 16384 unit| 8kB category| Resource Usage / Memory short_desc | Sets the number of shared memory buffers used by the server. extra_desc | context | postmaster vartype | integer source | configuration file min_val | 16 max_val | 1073741823 enumvals| boot_val| 1024 reset_val | 16384 sourcefile | /home/andrew/work/pgsql/inst/9.5/data/postgresql.conf sourceline | 113 pending_restart | f notice that "unit 8kB" line; the displayed integer value is in units of 8kB (which is the block size your server was compiled with, which you can also see as the block_size parameter). -- Andrew (irc:RhodiumToad)
Re: Interpreting shared_buffers setting
Hi, check for blocksize (8k) as factor. 8k*131072=1G regards Thomas Am 29.01.19 um 13:32 schrieb Bob Jolliffe: Excuse me if this is a silly question. I am trying to fiddle with shared_buffers setting on postgresql 10.6 on ubuntu 18.04 server. I have this at bottom of my config file: shared_buffers = 1GB Yet when I check the setting from pg_setting I see something quite different: postgres=# SELECT name, setting FROM pg_settings where name = 'shared_buffers'; name | setting +- shared_buffers | 131072 Is this a question of units? It looks like 128M. Note when I change the setting to 2GB in conf file I see 262144 from pg_setting. I am now unsure what the actual shared_buffers allocation is. I cant see anything in the docs which tells me how to interpret the integer. Any clarification welcome. Regards Bob
Interpreting shared_buffers setting
Excuse me if this is a silly question. I am trying to fiddle with shared_buffers setting on postgresql 10.6 on ubuntu 18.04 server. I have this at bottom of my config file: shared_buffers = 1GB Yet when I check the setting from pg_setting I see something quite different: postgres=# SELECT name, setting FROM pg_settings where name = 'shared_buffers'; name | setting +- shared_buffers | 131072 Is this a question of units? It looks like 128M. Note when I change the setting to 2GB in conf file I see 262144 from pg_setting. I am now unsure what the actual shared_buffers allocation is. I cant see anything in the docs which tells me how to interpret the integer. Any clarification welcome. Regards Bob