Thread: Adding variables for segment_size, wal_segment_size and block sizes
Now that we have customizable segment sizes for heap and WAL at compilation
time i would like to have some runtime variables to query that information
(besides pg_controldata). I can imagine to have the following names:
segment_size: Reports heap segment size
wal_segment_size: Reports wal segment size
block_size: Available yet
wal_block_size: wal block size
I'd like to implement them if we agree on them
-- Thanks
Bernd
Re: Adding variables for segment_size, wal_segment_size and block sizes
From
Euler Taveira de Oliveira
Date:
Bernd Helmle wrote: > segment_size: Reports heap segment size > wal_segment_size: Reports wal segment size > block_size: Available yet > wal_block_size: wal block size > +1. We already have block_size in GUC. -- Euler Taveira de Oliveira http://www.timbira.com/
Bernd Helmle wrote: > Now that we have customizable segment sizes for heap and WAL at compilation > time i would like to have some runtime variables to query that information > (besides pg_controldata). I can imagine to have the following names: > > segment_size: Reports heap segment size > wal_segment_size: Reports wal segment size > block_size: Available yet > wal_block_size: wal block size > > I'd like to implement them if we agree on them Bernd, have you made any progress on this? -- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + If your life is a hard drive, Christ can be your backup. +
--On Montag, Juni 30, 2008 18:47:33 -0400 Bruce Momjian <bruce@momjian.us>
wrote:
>>
>> I'd like to implement them if we agree on them
>
> Bernd, have you made any progress on this?
Here's a patch for this. I'll add it to the commit fest wiki page if it's
okay for you.
--
Thanks
Bernd
Attachment
On Thu, 2008-07-03 at 16:36 +0200, Bernd Helmle wrote: > --On Montag, Juni 30, 2008 18:47:33 -0400 Bruce Momjian <bruce@momjian.us> > wrote: > > >> > >> I'd like to implement them if we agree on them > > > > Bernd, have you made any progress on this? > > Here's a patch for this. I'll add it to the commit fest wiki page if it's > okay for you. It's small and uncontentious, please add it to the wiki. -- Simon Riggs www.2ndQuadrant.comPostgreSQL Training, Services and Support
Re: Adding variables for segment_size, wal_segment_size and block sizes
From
Abhijit Menon-Sen
Date:
At 2008-07-03 16:36:02 +0200, mailings@oopsware.de wrote: > > Here's a patch for this. I reviewed the patch, it basically looks fine. A few quibbles with the provided documentation: > + Reports the number of pages which can be stored within a file segment. > + The total physical size of a segment file in bytes can be determined by multiplying > + the <varname>block_size</varname> parameter with <varname>segment_size</varname>. I would say: Reports the number of blocks/pages which can be stored within a file segment. The total size of a segment file in bytesis equal to the <varname>segment_size</> multiplied by the <varname>block_size</>. > + Reports the size of a write ahead log disk block. It is determined by the value > + of <literal>XLOG_BLCKSZ</> when building the server. The default > + value is 8192 bytes. <varname>wal_block_size</varname> influences the total physical > + size of a write ahead log segment. See <xref > + linkend="guc-wal-segment-size"> for more information. > + </para> I'd change "write ahead log disk block" to "WAL disk block". How about this: Reports the size of a WAL disk block, as determined by the value of <literal>XLOG_BLCKSZ</> when compiling the server.The default is 8192 bytes. <varname>wal_block_size</> influences the total size of a WAL segment file. See <xreflinkend="guc-wal-segment-size"> for more information. > + Reports the number of pages within a write ahead log segment file. <varname>wal_segment_size</varname> multipliedwith <varname>wal_block_size</varname> gives the total physical size of a write ahead > + log segment file in bytes. Again, I'd say "WAL" here instead of "write ahead log", because the full form is clumsy in context. How about this: Reports the number of pages in a WAL segment file. The total size of a WAL segment file in bytes is equal to <varname>wal_segment_size</> multiplied by <varname>wal_block_size</>. What do you think? -- ams
On Thu, 2008-07-03 at 16:36 +0200, Bernd Helmle wrote: > --On Montag, Juni 30, 2008 18:47:33 -0400 Bruce Momjian <bruce@momjian.us> > wrote: > > >> > >> I'd like to implement them if we agree on them > > > > Bernd, have you made any progress on this? > > Here's a patch for this. I'll add it to the commit fest wiki page if it's > okay for you. I'm not sure why you've included "access/xlog_internal.h". All the #defines come from pgconfig.h Maybe that changed from when you started thinking about this? Other than that, no other comments. Looks good. -- Simon Riggs www.2ndQuadrant.comPostgreSQL Training, Services and Support
Abhijit Menon-Sen <ams@oryx.com> writes:
> At 2008-07-03 16:36:02 +0200, mailings@oopsware.de wrote:
>> Here's a patch for this.
> I reviewed the patch, it basically looks fine. A few quibbles with the
> provided documentation:
Applied, with ams' doc changes and some further wordsmithing.
regards, tom lane