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Home > Archive > SQL Anywhere Feedback > November 2005 > dbeng9 -cr- should be the default
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dbeng9 -cr- should be the default
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| Breck Carter [TeamSybase] 2005-11-15, 11:23 am |
| Cache warming is a mildly-nice-to-have feature for databases that run
with gigantic caches and are rarely stopped and started.
For databases that run with gigantic caches but are OFTEN stopped and
started, the feature can be a performance KILLER... truly annoying as
the engine bogs down reading a ton of pages it's never gonna use.
IMO the default should be -cr- rather than -cr+, since -cr- is the
legacy behavior.
Breck
--
SQL Anywhere Studio 9 Developer's Guide
Buy the book: http://www.amazon.com/exec/obidos/A...7/risingroad-20
bcarter@risingroad.com
RisingRoad SQL Anywhere and MobiLink Professional Services
www.risingroad.com
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| Mark Culp 2005-11-15, 1:23 pm |
| Hmmm, Cache warming was implemented specifically for the case when a
database is started and stopped often. e.g. Many customers start and
stop databases often, and they want good performance when they run their
first query.
The idea of warming the cache using the same pages that were read the
last time the database was started does make the assumption that the
initial queries that are given will be same (or similar) to the ones
given when the database was last started. Many applications do this.
Cache warming is also suppose to stop as soon as a client issues a
query. ! Is this not happening for you?
--
Mark Culp
SQLAnywhere Research and Development
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"Breck Carter [TeamSybase]" wrote:
>
> Cache warming is a mildly-nice-to-have feature for databases that run
> with gigantic caches and are rarely stopped and started.
>
> For databases that run with gigantic caches but are OFTEN stopped and
> started, the feature can be a performance KILLER... truly annoying as
> the engine bogs down reading a ton of pages it's never gonna use.
>
> IMO the default should be -cr- rather than -cr+, since -cr- is the
> legacy behavior.
>
> Breck
>
> --
> SQL Anywhere Studio 9 Developer's Guide
> Buy the book: http://www.amazon.com/exec/obidos/A...7/risingroad-20
> bcarter@risingroad.com
> RisingRoad SQL Anywhere and MobiLink Professional Services
> www.risingroad.com
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| Breck Carter [TeamSybase] 2005-11-15, 1:23 pm |
| On 15 Nov 2005 09:31:05 -0800, Mark Culp
< reply_to_newsgroups_
only_please_nospam_m
ark.culp@iAnywhere.com>
wrote:
>Hmmm, Cache warming was implemented specifically for the case when a
>database is started and stopped often. e.g. Many customers start and
>stop databases often, and they want good performance when they run their
>first query.
>
>The idea of warming the cache using the same pages that were read the
>last time the database was started does make the assumption that the
>initial queries that are given will be same (or similar) to the ones
>given when the database was last started. Many applications do this.
>
>Cache warming is also suppose to stop as soon as a client issues a
>query. ! Is this not happening for you?
Good question, I cannot remember. I'll go and rip out all the -cr-
settings, report on the results later.
Breck
--
SQL Anywhere Studio 9 Developer's Guide
Buy the book: http://www.amazon.com/exec/obidos/A...7/risingroad-20
bcarter@risingroad.com
RisingRoad SQL Anywhere and MobiLink Professional Services
www.risingroad.com
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