IDS Forum

RE: How to Store Table in RAM in Informix

Posted By: Walter Milan
Date: Thursday, 17 July 2008, at 12:38 p.m.

In Response To: Re: How to Store Table in RAM in Informix (Keith Simmons)

You do not specify what version you use. As somebody told before the set
residency feature was disabled around 9.XX version.
There is another way to try to keep some pages on memory provided by the
variable page size capability.
Create a dbspace with another pagesize than your other tables. Put your
tables or indexes you want to stay longer on memory on that dbspace. You
also have to define a buffer pool for that dbspace which will be the
resident portion that will keep in memory all those pages you read.
In our environment, heavily OLTP, we put only some indexes on those
dbspaces.

Don't forget that Informix use LRU mechanism, so if you have a page on
memory used a lot, most likely that page will remain in memory. And then
residency becomes a moot point.

Walter Milan
DBA

-----Original Message-----
From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of
Keith Simmons
Sent: Thursday, July 17, 2008 10:53 AM
To: ids@iiug.org
Subject: Re: How to Store Table in RAM in Informix [12754]

2008/7/17 Keith Simmons <smiley73@googlemail.com>:
> 2008/7/17 OMER KHAN <oskhan@i2cinc.com>:
>> Hello All,
>>
>> I want to know that is there any funtionality of Informix that would
allow
> me
>> to store some of the tables in the RAM.
>>
>> I want to do this to increase the query performance?
>>
>> Is there any way, is it possible?
>>
>> I will be waiting for the response. Thanks.
>> Omer Saeed Khan
>>
>>
>>
>
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>>
>>
> Omer
>
> Why do you think RAW tables will increase query performance? You shold

> be looking at indexes, update statistics, number of buffers, ReadAhead

> settings, possibly LRU settings, and at a lower level disk layout,
> disk controllers and/or system memory.
> Post your O/S, IDS version and some stats, these will be of more use
> than a nebulous question that will not provide the solution you need.
>
> Keith
>
>
>
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>
>
My apologies, I misread RAM for RAW, but some of the comments still
apply.
However if your tables are small and frequently used thay will tend to
remain in RAM (buffers) anyway. If you are getting better than 99%
Read Buffer hits from onstat -p, then most of you reads are from
buffers and will not get much faster. Let the engine sort out the
memory allocatio, just give it as much memory as possible to play
with.

Keith

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Forum Note: Use "Reply" to post a response in the discussion forum.

Messages In This Thread

• How to Store Table in RAM in Informix
  OMER KHAN -- Thursday, 17 July 2008, at 11:06 a.m.
  • Re: How to Store Table in RAM in Informix
    Willy Calderón -- Thursday, 17 July 2008, at 11:41 a.m.
  • Re: How to Store Table in RAM in Informix
    Keith Simmons -- Thursday, 17 July 2008, at 11:42 a.m.
    • Re: How to Store Table in RAM in Informix
      Keith Simmons -- Thursday, 17 July 2008, at 11:52 a.m.
      • RE: How to Store Table in RAM in Informix
        Walter Milan -- Thursday, 17 July 2008, at 12:38 p.m.
  • Re: How to Store Table in RAM in Informix
    Adam Tauno Williams -- Thursday, 17 July 2008, at 11:47 a.m.
  • Re: How to Store Table in RAM in Informix
    Manoj Mohan -- Thursday, 17 July 2008, at 11:49 a.m.
  • Re: How to Store Table in RAM in Informix
    Art Kagel -- Thursday, 17 July 2008, at 12:21 p.m.
    • Re: How to Store Table in RAM in Informix
      OMER KHAN -- Thursday, 17 July 2008, at 1:23 p.m.
      • Re: How to Store Table in RAM in Informix
        Art Kagel -- Thursday, 17 July 2008, at 1:42 p.m.
  • Re: How to Store Table in RAM in Informix
    Obnoxio The Clown -- Thursday, 17 July 2008, at 2:41 p.m.
  • RE: How to Store Table in RAM in Informix
    Hrvoje Zokovic -- Thursday, 17 July 2008, at 3:02 p.m.
  • Re: How to Store Table in RAM in Informix
    Jonathan Smaby -- Thursday, 17 July 2008, at 6:32 p.m.
    • RE: How to Store Table in RAM in Informix
      Mark Tyrer -- Friday, 18 July 2008, at 3:23 a.m.
  • Re: How to Store Table in RAM in Informix
    MARS CHEN -- Thursday, 17 July 2008, at 8:21 p.m.

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