Schema Size

Increase the cache memory to migrate large and extremely large schemas.

Large Schemas

Default cache settings for large schemas may be too small and can exhaust dynamic memory in the iqsrv16 server. Use the -c switch to increase the server cache memory and -new_startline to pass the switch to the server.

A diagnostic example includes these switches:

-ca 1
-c 1000m
-o /iq15outputdir/iq16console.out

-ca 1 – enables dynamic catalog cache sizing, and logs memory cache statistics to the console.
-c 1000m – sets the initial catalog cache at 1GB.
-o /outputdir/iq16console.out – specifies the log file for console output.

Use a text editor to xamine the .out file log entries. Watch how the catalog store adjusts the cache and determines if the setting is appropriate.

Note: The value shown for -c is in bytes. Set switches appropriately for your system. To specify megabytes, use the m suffix, as shown.

Extremely Large Schemas

Running iqunload in schema unload mode (iqunload -n) generates a single script (reload.sql ) that includes the entire legacy schema. In some cases, you may need to break a very large reload.sql file into pieces that can be executed sequentially. This also helps the server manage the cache.

If iqunload fails in migration mode (iqunload -au) because dynamic memory is exhausted, set the cache settings as high as your hardware and operating system limitations allow. If the failure continues, contact SAP Sybase for assistance.