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Why COLCARD is sometimes bigger than CARD after RUNSTATS?

Question & Answer


Question

Why COLCARD is sometimes bigger than CARD after RUNSTATS?

Answer

This symptom is normal if new rows are inserted into the table during runstats. User can try runstats with "ALLOW READ ACCESS" option. This will block any modification to the table during runstats. But, in production environment, it is usually undesirable to block writing to the table, especially if runstats takes a long time.

Starting from v97fp9, for the purpose of mimic statistics in test environment, db2 has an undocumented registry, when set, it will allow "UPDATE SYSSTAT" to go through even if the statistics are inconsistent.

db2set DB2_STATISTICS=USCC:0
recycle the instance

[{"Product":{"code":"SSEPGG","label":"Db2 for Linux, UNIX and Windows"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Component":"Compiler - Runstats","Platform":[{"code":"PF002","label":"AIX"},{"code":"PF010","label":"HP-UX"},{"code":"PF016","label":"Linux"},{"code":"PF027","label":"Solaris"},{"code":"PF033","label":"Windows"}],"Version":"9.8;9.7;10.1;10.5","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
16 June 2018

UID

swg21985376