Suggestion needed for IQ upgrade 16 from 15.4

[Former Member]

Planning to upgrade IQ 15.4 to IQ 16 ..  Database size : 15 TB

Wanted to check . Is it mandatory rebuild index for  wide columns ..  ( Not sure how long rebuild will take ) ..

For rebuilding index for all wide columns in database .  Can I run below command instead of  running for individual table/column .

sp_iqrebuildindexwide [ table_name ] [, table_owner] [, level]

sp_iqrebuildindexwide NULL,NULL,1

So if I pass table_name and table_ower as NULL  . Will it  rebuild index for whole database for  wide column .

Appreciate your suggestion .

Thanks

Ajay Pandey

[markmumy · Accepted solution]

The rebuild is recommended for all columns so that we can put them in the newer, faster format.  Also, for character fields we also capture more stats about the data in IQ 16.  If you don't rebuild we will lose those stats and consequently not give the optimizer more information to feed better/faster results.

I will say that they don't all have to be done at once.  You can trickle in the changes over time by running the commands during off hours or low use times.  If I were to prioritize, I would start with your most active, largest tables so that we can realize the space savings of the new index structures and boost performance.

Mark

[Former Member · Accepted solution]

That is the plan to rebuild default index over time for all tables but as per document .

databases migrated to SAP Sybase IQ 16.0 must be rebuilt before the database engine can perform read/write activities on them

Remarks

CHAR, VARCHAR, BINARY, and VARBINARY columns wider than 255 characters, as well as all LONG VARCHAR and LONG BINARY columns in databases migrated to SAP Sybase IQ 16.0 must be rebuilt before the database engine can perform read/write activities on them

SAP Sybase IQ implicitly rebuilds these type of columns the first time a table is opened for read-write access. sp_iqrebuildindexwide explicitly rebuilds these columns to the state defined by the level parameter.

Regards

Ajay Pandey

[markmumy · Accepted solution]

That's not quite true.  IQ can operate on the older structures without issue.  It is strongly recommended to convert as there are many performance and stability improvements.  To say it is required is a bit of a stretch.

The issues are that they are older, slower structures that take up more space.  Also, the FP3 is known to have issues.  If you don't rebuild them, you may have a latent issue until you access it or change the data via the application.  Better to know about it before running in production.

Mark