"FUNCTION: DB2 UDB, sort/list services, sqlsOptimizeNumMergeRuns, probe:10
MESSAGE : ADM9000W Prefetching was disabled during sort merge; performance may
be suboptimal. If this message persists, consider increasing the
buffer pool size for temporary table space "TEMPSPACE1" (ID "1") or
increase the value of the SORTHEAP DB configuration parameter to
reduce the extent of sort spilling."
This is a warning. Not an error. Try the following:
- Get the value of SORTHEAP param for the database. On Linux:
db2 get db cfg for <dbname> | grep SORTHEAP - Increase the value by the command:
db2 update db cfg for <dbname> using SORTHEAP <newvalue> - Use db2look command and check what buffer is used by the TEMPSPACE1.
db2look -d <dbname> (then you need to go through the output generated by this command) - Increase the number of pages of this bufferpool using ALTER BUFFERPOOL.
This is a general recommendation. You need to check the amount of RAM on your server, consumption of resources by other databases and so on and use values that reflect your environment.
Sources:
ALTER BUFFERPOOL - https://www.ibm.com/support/knowledgecenter/en/SSEPGG_9.7.0/com.ibm.db2.luw.sql.ref.doc/doc/r0000885.html