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Collecting Migration Statistics

COLLECT STATS is used in Teradata for collecting optimizer statistics, which would be used for query performance. GaussDB T, GaussDB A, and GaussDB(DWS) use the ANALYZE statement to support COLLECT STATS.

See: 1.

Input - COLLECT STATISTICS

COLLECT STAT tab1 COLUMN (c1, c2);

Output

ANALYZE tab1 (c1, c2);

Input - COLLECT STATISTICS

COLLECT STATISTICS
  COLUMN (customer_id,customer_name) 
, COLUMN (postal_code) 
, COLUMN (customer_address) 
ON customer_t;

Output

ANALYZE customer_t (
     customer_id
     ,customer_name
     ,postal_code
     ,customer_address
)
;

Input - COLLECT STATISTICS with COLUMN

COLLECT STATISTICS
  COLUMN (
  Order_Date
  -- ,o_orderID
/*COLLECT 
STATISTICS*/
  ,Order_ID
     )  
ON order_t;

Output

ANALYZE order_t (
    Order_Date
     ,Order_ID
)
;

Input - COLLECT STATISTICS with Schema Name

COLLECT STATS COLUMN (
     empno
     ,ename
)
     ON ${schemaname}."usrTab1"
;

Output

ANALYZE ${schemaname}."usrTab1" 
(
     empno
     ,ename
)
;

COLLECT STATISTICS

Collect statistics based on sampling percentage.

Input

COLLECT STATISTICS 
 USING SAMPLE 5.00 PERCENT 
 COLUMN ( CDR_TYPE_KEY ) , 
 COLUMN ( PARTITION ) , 
 COLUMN ( SRC ) , 
 COLUMN ( PARTITION,SBSCRPN_KEY ) 
 ON DT_SDM.FCT_OTGO_NTWK_ACTVY_DAILY ;

Output

SET
default_statistics_target = 5.00 ;
ANALYZE DT_SDM.FCT_OTGO_NTWK_ACTVY_DAILY (CDR_TYPE_KEY) ;
ANALYZE DT_SDM.FCT_OTGO_NTWK_ACTVY_DAILY (PARTITION) ;
ANALYZE DT_SDM.FCT_OTGO_NTWK_ACTVY_DAILY (SRC) ;
ANALYZE DT_SDM.FCT_OTGO_NTWK_ACTVY_DAILY (PARTITION,SBSCRPN_KEY) ;
 RESET default_statistics_target ;