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DSI cfg tunning

3 posts in General Discussion Last posting was on 2012-11-01 17:46:34.0Z
Isabella Posted on 2012-10-30 16:33:22.0Z
From: Isabella <isabella.ghiurea@nrc-cnrc.gc.ca>
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Hi All,
I'm running Rep server Replication Server/15.2/EBF 17699 ESD#2/Linux
Intel/Linux 2.6.9-42.ELsmp i686/1/OPT/Wed Apr 21 18:20:37 2010
with ASE 15.5 EBF 5 , cfg for warm standby db replication.

I start having latency > 10 hours between primary db and replicate db ,
I cfg/tune rep agent in primary db for" batch size, send buffer size to
16k " , there is more > 12 GB of data in stable queues waiting to be
replicated to standby db.
I would like to know if there any cfg /tuning param for replicate DSI I
can help to speed up the writes to standby db ?

Thank you
Isabella


"Mark A. Parsons" <iron_horse Posted on 2012-10-30 23:35:52.0Z
From: "Mark A. Parsons" <iron_horse@no_spamola.compuserve.com>
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Subject: Re: DSI cfg tunning
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While some dsi configurations may help, that large of a latency usually comes down to other non-DSI related issues, eg:

- lot of update/delete activity on tables with large numbers of columns and no repdef/primary-key definitions; means the
repserver and RDS have to spend a lot of time building/parsing excessively long WHERE clauses

- if the RDS is ASE 15.x and statement cache is disabled, then every query submitted by the DSI has to be parsed; I've
seen replication latency jump from 50-100 minutes for RDS=ASE.12.5.4 to 24+ hrs for RDS=ASE.15.x all because the ASE
15.x dataserver did not have statement cache enabled

- obviously blocking by some other process in the RDS could lead to excessive latency

- really large transactions from the PDS can delay processing as the repserver can end up spending a lot of time doing
disk IOs trying to the large transactions with relatively small amounts of memory

If you're doing a lot of inserts you may find that enabling dsi_bulk_copy helps some.

You really need to find out *why* you have excessive latency; once you know *where* your latency issues are coming from
then you can start making tuning/configuration changes to your repserver, dataservers and/or processes that are
generating the volumes of log activity in the PDS.

On 10/30/2012 10:33, Isabella wrote:
>
> Hi All,
> I'm running Rep server Replication Server/15.2/EBF 17699 ESD#2/Linux Intel/Linux 2.6.9-42.ELsmp i686/1/OPT/Wed Apr 21
> 18:20:37 2010
> with ASE 15.5 EBF 5 , cfg for warm standby db replication.
>
> I start having latency > 10 hours between primary db and replicate db , I cfg/tune rep agent in primary db for" batch
> size, send buffer size to 16k " , there is more > 12 GB of data in stable queues waiting to be replicated to standby db.
> I would like to know if there any cfg /tuning param for replicate DSI I can help to speed up the writes to standby db ?
>
> Thank you
> Isabella


Manish Negandhi [TeamSybase] Posted on 2012-11-01 17:46:34.0Z
From: "Manish Negandhi [TeamSybase]" <negandhi.manish_nospam@gmail.com>
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Article PK: 870429

In addition to what Mark mentioned, in order to tune DSI performance, you
might want to check how parallel DSI works

http://infocenter.sybase.com/help/topic/com.sybase.infocenter.dc32518.1570/doc/html/san1292613328220.html

-HTH
Manish Negandhi
[TeamSybase]

"Mark A. Parsons" wrote in message news:50906458$1@forums-1-dub...

While some dsi configurations may help, that large of a latency usually
comes down to other non-DSI related issues, eg:

- lot of update/delete activity on tables with large numbers of columns and
no repdef/primary-key definitions; means the
repserver and RDS have to spend a lot of time building/parsing excessively
long WHERE clauses

- if the RDS is ASE 15.x and statement cache is disabled, then every query
submitted by the DSI has to be parsed; I've
seen replication latency jump from 50-100 minutes for RDS=ASE.12.5.4 to 24+
hrs for RDS=ASE.15.x all because the ASE
15.x dataserver did not have statement cache enabled

- obviously blocking by some other process in the RDS could lead to
excessive latency

- really large transactions from the PDS can delay processing as the
repserver can end up spending a lot of time doing
disk IOs trying to the large transactions with relatively small amounts of
memory

If you're doing a lot of inserts you may find that enabling dsi_bulk_copy
helps some.

You really need to find out *why* you have excessive latency; once you know
*where* your latency issues are coming from
then you can start making tuning/configuration changes to your repserver,
dataservers and/or processes that are
generating the volumes of log activity in the PDS.

On 10/30/2012 10:33, Isabella wrote:
>
> Hi All,
> I'm running Rep server Replication Server/15.2/EBF 17699 ESD#2/Linux
> Intel/Linux 2.6.9-42.ELsmp i686/1/OPT/Wed Apr 21
> 18:20:37 2010
> with ASE 15.5 EBF 5 , cfg for warm standby db replication.
>
> I start having latency > 10 hours between primary db and replicate db , I
> cfg/tune rep agent in primary db for" batch
> size, send buffer size to 16k " , there is more > 12 GB of data in stable
> queues waiting to be replicated to standby db.
> I would like to know if there any cfg /tuning param for replicate DSI I
> can help to speed up the writes to standby db ?
>
> Thank you
> Isabella