IA column analysis

vamsi_4a6 · Post by **vamsi_4a6** » Fri Aug 28, 2015 4:59 am

When we are running column analysis on a table it is taking long time(more than 3 to 4 hours)even though volume of data is less on table.Not able to figure it out the root cause and from where i have start to find the issue.

rkashyap · Post by **rkashyap** » Fri Aug 28, 2015 6:26 am

Is the column analysis slow for a specific table or is this true for all tables? Is the table local/remote, indexed ... how big? Also share information about your hardware.

vamsi_4a6 · Post by **vamsi_4a6** » Sat Aug 29, 2015 4:28 am

It is slow for all tables and how to get below information without checking with admin

Is the table local/remote, indexed ... how big? Also share information about your hardware.

My admin is not willing to share that information as per company policies

qt_ky · Post by **qt_ky** » Mon Aug 31, 2015 7:27 am

Find an admin who will actually help!?! In this case, open a problem ticket about the poor performance and assign it to the admin.

ray.wurlod · Post by **ray.wurlod** » Mon Aug 31, 2015 11:40 pm

Column analysis should not use any indexes; basically it issues the query SELECT * FROM tablename against the database (or just the specified columns if relevant).

Sampling is performed within Information Analyzer.

The only time indexing might be useful is a virtual table in Information Analyzer that includes a WHERE clause.

Remote tables can be expected to deliver results more slowly than local ones; this is a network issue, not an Information Analyzer issue. It would not matter which client you used.

vamsi_4a6 · Post by **vamsi_4a6** » Fri Sep 04, 2015 2:11 am

1)can i run column analysis by submitting a sql query because i want to restrict the data before running column analysis?If not how to fetch limited data without using sample technique?

rjdickson · Post by **rjdickson** » Fri Sep 04, 2015 7:42 am

Hi,

You can create a virtual table that applies a 'where' clause to reduce the rows/columns being used. You would then use that virtual table as input to your column analysis.

I hope this helps!

vamsi_4a6 · Post by **vamsi_4a6** » Fri Sep 04, 2015 8:37 am

I found the option in IA for virtual column but i did not find any option related for virtual table.where exactly it is present?

rjdickson · Post by **rjdickson** » Fri Sep 04, 2015 8:40 am

Hi,

You do it from the Column Analysis workspace.
Please see: https://www-01.ibm.com/support/knowledg ... ml?lang=en

vamsi_4a6 · Post by **vamsi_4a6** » Fri Sep 04, 2015 8:51 am

Thanks alot for input.How to give this virtual table as input while running columns analysis for a particular table.because i can see only Run now,sample ands chedule options

qt_ky · Post by **qt_ky** » Fri Sep 04, 2015 7:18 pm

From the Column Analysis workspace, select the virtual table you created, then click on the Run Column Analysis task. Selecting Run Now is fine, then click Submit.

vamsi_4a6 · Post by **vamsi_4a6** » Fri Sep 04, 2015 10:47 pm

I do not find any option to select the Virtual table .could you please provide details where exactly i need to select

ray.wurlod · Post by **ray.wurlod** » Fri Sep 04, 2015 11:12 pm

You have to "create" the virtual table definition first - by specifying the columns and WHERE clause and giving it a name. Once you have saved this it will appear in the list of tables available for running Column Analysis (and, later, the other analyses).