Informatica性能调优(初级)(6)

Informatica性能调优(初级)

原文

INFORMATICA BASIC TUNING GUIDELINES

Dan Linstedt

The following points are high-level issues on where to go to perform "tuning" in Informatica's products. These are NOT permanent instructions, nor are they the end-all solution. Just some items (which if tuned first) might make a difference. The level of skill available for certain items will cause the results to vary.

To 'test' performance throughput it is generally recommended that the source set of data produce about 200,000 rows to process. Beyond this - the performance problems / issues may lie in the database - partitioning tables, dropping / re-creating indexes, striping raid arrays, etc... Without such a large set of results to deal with, you're average timings will be skewed by other users on the database, processes on the server, or network traffic. This seems to be an ideal test size set for producing mostly accurate averages.

Try tuning your maps with these steps first. Then move to tuning the session, iterate this sequence until you are happy, or cannot achieve better performance by continued efforts. If the performance is still not acceptable,. then the architecture must be tuned (which can mean changes to what maps are created). In this case, you can contact us - we tune the architecture and the whole system from top to bottom.

KEEP THIS IN MIND: In order to achieve optimal performance, it's always a good idea to strike a balance between the tools, the database, and the hardware resources. Allow each to do what they do best. Varying the architecture can make a huge difference in speed and optimization possibilities.

1. Utilize a database (like Oracle / Sybase / Informix / DB2 etc...) for significant data handling operations (such as sorts, groups, aggregates). In other words, staging tables can be a huge benefit to parallelism of operations. In parallel design - simply defined by mathematics, nearly always cuts your execution time. Staging tables have many benefits. Please see the staging table discussion in the methodologies section for full details.

2. Localize. Localize all target tables on to the SAME instance of Oracle (same SID), or same instance of Sybase. Try not to use Synonyms (remote database links) for anything (including: lookups, stored procedures, target tables, sources, functions, privileges, etc...). Utilizing remote links will most certainly slow things down. For Sybase users, remote mounting of databases can definitely be a hindrance to performance.

3. If you can - localize all target tables, stored procedures, functions, views, sequences in the SOURCE database. Again, try not to connect across synonyms. Synonyms (remote database tables) could potentially affect performance by as much as a factor of 3 times or more.

4. Remove external registered modules. Perform pre-processing / post-processing utilizing PERL, SED, AWK, GREP instead. The Application Programmers Interface (API) which calls externals is