Re: increasing the default WAL segment size

Hello,

Thank you testing. I just wanted to confirm few things since I do not have
linux32 setup yet.

On Fri, Mar 10, 2017 at 1:09 PM, tushar <tushar.ahuja@enterprisedb.com>
wrote:

> On 03/10/2017 11:23 AM, Beena Emerson wrote:
>
>
>> Thank you for your reviews Kuntal, Jim, Ashutosh
>
> Attached in an updated 02 patch which:
>
>    1. Call RetrieveXLogSegSize(conn) in pg_receivewal.c
>    2. Remove the warning in Windows
>    3. Change PATH_MAX in pg_waldump with MAXPGPATH
>
> Regarding the usage of the wal file size as the XLogSegSize, I agree with
> what Robert has said. Generally, the wal size will be of the expected
> wal_segment_size and to have it any other size, esspecially of a valid
> power2 value is extremely rare and I feel it is not a major cause of
> concern.
>
> We (Prabhat and I) have started basic  testing of this feature -
> 2 quick issue -
>
> 1)at the time of initdb, we have set - "--wal-segsize 4"  ,so all the WAL
> file size should be 4 MB each  but in the postgresql.conf file , it is
> mentioned
>
> #wal_keep_segments = 0          # in logfile segments,* 16MB each*; 0
> disables
>
> so the comment  (16MB ) mentioned against parameter 'wal_keep_segments'
> looks wrong , either we should remove this or modify it .
>
> 2)Getting "Aborted (core dumped)"  error at the time of running
> pg_basebackup  ,
> *(this issue is only coming on Linux32 ,not on Linux64) * we have  double
> check to confirm it .
>
> Steps to reproduce on Linux32
> ===================
> fetch the sources
> apply both the patches
>  ./configure --with-zlib   --enable-debug  --enable-cassert
> --enable-depend --prefix=$PWD/edbpsql --with-openssl CFLAGS="-g -O0"; make
> all install
> Performed initdb with switch "--wal-segsize 4"
>

Does the crash occur with only size 4?


> start the server
> run pg_basebackup
>
> [centos@tushar-centos bin]$ ./pg_basebackup -v -D /tmp/myslave
> *** glibc detected *** ./pg_basebackup: free(): invalid pointer:
> 0x08da7f00 ***
>
> [centos@tushar-centos bin]$
>
> same scenario is working fine against HEAD (v10 ) on Linux32 [i.e no patch
> applied]
>
> [centos@tushar-centos bin]$ ./pg_basebackup --verbose -D /tmp/slave11
> pg_basebackup: initiating base backup, waiting for checkpoint to complete
> pg_basebackup: checkpoint completed
> pg_basebackup: transaction log start point: 0/2800024 on timeline 1
> pg_basebackup: starting background WAL receiver
> pg_basebackup: transaction log end point: 0/28000E4
> pg_basebackup: waiting for background process to finish streaming ...
> pg_basebackup: base backup completed
> [centos@tushar-centos bin]$
>

Just to confirm, was this done with configure flag --with-wal-segsize=4 ?


Thank you,

Beena Emerson

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