Re: Support for shared memory access in Connector/J? - Paul Palaszewski - com.mysql.lists.java

3 messages in com.mysql.lists.javaRe: Support for shared memory access ...

From	Sent On	Attachments
Paul Palaszewski	07 Sep 2006 05:28
Mark Matthews	07 Sep 2006 06:29
Paul Palaszewski	07 Sep 2006 07:01

Subject:	Re: Support for shared memory access in Connector/J?
From:	Paul Palaszewski (paul...@bdm-systems.com)
Date:	09/07/2006 07:01:01 AM
List:	com.mysql.lists.java

Hi Mark!

Thanks for the quick response. My expierience with differences between shared memory and pipes is based on some development tools which don't access disks so I think you're right that it should not make a difference for mysql.

My app is our bluecube datawarehouse engine. It is implemented in java and uses mysql or sql server as storage backend. We mainly sell it as powerful yet easy to use etl and mapping tool, but we performance is also one of our main selling arguments. Over the last 3 years we spent a lot of effort into tuning, starting with full indexing on generated tables with loaded data, server settings, regular code reviews and profiling sessions and so on. We are at the point where we import and aggregate (incl. a slow extract db and simple transformations and lookups) several millions of sales records with approx. 150 fields (10gb data) on an average 2 year old server within less than 1 hour - yet we are sure that we still can make it noticeable faster and want to do so ;-)

Best regards, Paul

Mark Matthews schrieb:

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Paul Palaszewski wrote:

Hi!

I'm running various mysql servers including 5.0.24a with connector/j 3.1.13 and 5.0.3. I successfully used named pipes as alternative to sockets and was wondering if there is any support for shared memory access? Suppose it would be another socket factory, but have not found anything in docs or in code.

Paul,

It's not supported, and isn't planned to be, as the major use for shared memory in the server is for Windows 95/98, which doesn't have named pipes (and is now a "dead" platform).

If it's not supported, please document that. And if is it planed ... when could it be available?

With the experience from other applications I suppose shared memory is again significantly faster than named pipes like named pipes are compared to tcp ip. Does anybody have experience from other drivers, what performance difference the difference between mysql named pipes and mysql shared memory is?

My guess is it isn't, given that under the hood named pipes probably use some shared-memory like mechanism. I'd also have a look at your application, because if it's a "normal" database application, you shouldn't see a large (i.e. orders of magnitude) difference in application performance based on what "transport" you use for the database RPCs, compared to the kinds of performance impact correctly written queries with proper indexes and correct tuning of buffers on the server (to avoid disk I/O) you will see.

-Mark

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