Checking for missing statistics in Watson Query
You can use SQL to determine whether statistics for a specific virtual table are missing.
To determine whether table-level statistics are missing for a virtual table, use the following query.
select cast(TABNAME as varchar(25)), TYPE, COLCOUNT, STATS_TIME
from SYSCAT.TABLES
where TABSCHEMA='schema'
and CARD=-1;
Replace schema with the schema name of the virtual table. The statement returns a list of all the objects in the schema that have a CARD value of -1, which is an indication that table-level statistics have not been collected.
To determine whether column-level statistics are missing for a virtual table, use the following query.
select cast (COLNAME as varchar(25))
from SYSSTAT.COLUMNS
where TABSCHEMA='schema'
and TABNAME='table_name'
and COLCARD=-1
and NUMNULLS=-1;
Replace schema with the schema name and table_name with the name of the virtual table. The statement returns a list of all the objects in the schema that have a COLCARD and NUMNULLS value of -1, which is an indication that column-level statistics have not been collected.