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gather statistics auto

edited Feb 20, 2020 4:00AM in SQL Performance (MOSC) 11 commentsAnswered

Hi All,

After migrating my old database to 12cR2 from 11gR2 I find some queries very slow.

The auto statistics collection is enabled. Checking on my selected tables (queries slow) I find the LAST_ANALYZED column as of current date.

But when I compare the records of NUM_ROWS (from DBA_TABLES) and actual record count, certain tables match the count, certain table have a big difference in spite of LAST_ANALYZED is updated to current date.

Checking the Global parameters ; I have changed the degree from NULL to 4 .

Automatic Stats Gathering Job - Parameters

==========================================

AUTOSTATS_TARGET:  AUTO

CASCADE:           DBMS_STATS.AUTO_CASCADE

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