Re: increasing the default WAL segment size

On Fri, Mar 31, 2017 at 10:40 AM, Beena Emerson <memissemerson(at)gmail(dot)com> wrote:
> On 30 Mar 2017 15:10, "Kuntal Ghosh" <kuntalghosh(dot)2007(at)gmail(dot)com> wrote:

>> 03-modify-tools.patch - Makes XLogSegSize into a variable, currently set
>> as
>> XLOG_SEG_SIZE and modifies the tools to fetch the size instead of using
>> inbuilt value.
> Several methods are declared and defined in different tools to fetch
> the size of wal-seg-size.
> In pg_standby.c,
> RetrieveXLogSegSize() - /* Set XLogSegSize from the WAL file header */
>
> In pg_basebackup/streamutil.c,
> on behaRetrieveXLogSegSize(PGconn *conn) - /* set XLogSegSize using
> SHOW wal_segment_size */
>
> In pg_waldump.c,
> ReadXLogFromDir(char *archive_loc)
> RetrieveXLogSegSize(char *archive_path) /* Scan through the archive
> location to set XLogSegsize from the first WAL file */
>
> IMHO, it's better to define a single method in xlog.c and based on the
> different strategy, it can retrieve the XLogSegsize on behalf of
> different modules. I've suggested the same in my first set review and
> I'll still vote for it. For example, in xlog.c, you can define
> something as following:
> bool RetrieveXLogSegSize(RetrieveStrategy rs, void* ptr)
>
> Now based on the RetrieveStrategy(say Conn, File, Dir), you can cast
> the void pointer to the appropriate type. So, when a new tool needs to
> retrieve XLogSegSize, it can just call this function instead of
> defining a new RetrieveXLogSegSize method.
>
> It's just a suggestion from my side. Is there anything I'm missing
> which can cause the aforesaid approach not to be working?
> Apart from that, I've nothing to add here.
>
>
>
> I do not think a generalised function is a good idea. Besides, I feel the
> respective approaches are best kept in the modules used also because the
> internal code is not easily accessible by utils.
>
Ahh, I wonder what the reason can be. Anyway, I'll leave that decision
for the committer. I'm moving the status to Ready for committer.

I've only tested the patch in my 64-bit linux system. It needs some
testing on other environment settings.

--
Thanks & Regards,
Kuntal Ghosh
EnterpriseDB: http://www.enterprisedb.com