hi friends,
i have query like below.
in my merge table there 50 million reocords i.e.FILE_LEVEL_SUMM_TAPOUT
and i have append nologging as hint, so please let me know , how Appned and Nologgin improve the performance of query .
MERGE /*+ APPEND NOLOGGING*/ INTO FILE_LEVEL_SUMM_TAPOUT FTO
USING ( SELECT
T.fileid,
T.FAT_LOCAL,
T.FAT_UTC_TIME_OFFSET,
T.TCT_UTC_TIME_OFFSET
FROM TAPHEADER T
WHERE FILEID =P_FILEID)AA
ON (FTO.FILE_ID = AA.FILEID)
WHEN MATCHED THEN
UPDATE SET FTO.TCT_UTC_TIME_OFFSET=AA.TCT_UTC_TIME_OFFSET ,
FTO.FAT_LOCAL=AA.FAT_LOCAL,
FTO.FAT_UTC_TIME_OFFSET=FAT_UTC_TIME_OFFSET,
FTO.FILE_STATUS=999;