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Message Posted: Tue, 24 Jul 2007 @ 22:03:42 GMT
Pls find the following explain plan for step4.
4) We execute the following steps in parallel. 1) We do an all-AMPs JOIN step from Spool 4 (Last Use) by way of an all-rows scan, which is joined to Spool 5 (Last Use) by way of an all-rows scan. Spool 4 and Spool 5 are left outer joined using a product join, with a join condition of ( "(imei <= end_imei) AND (imei >= beg_imei)"). The result goes into Spool 6 (all_amps), which is built locally on the AMPs. The size of Spool 6 is estimated with no confidence to be 300,410,527 rows. The estimated time for this step is 4 minutes and 30 seconds. 2) We do an all-AMPs RETRIEVE step from mktdb.esn_ref by way of an all-rows scan with no residual conditions into Spool 7 (all_amps), which is duplicated on all AMPs. The size of Spool 7 is estimated with high confidence to be 2,950,828 rows. The estimated time for this step is 3.20 seconds.
The above explain step 4 trying to build SPOOL 6 using SPOOL 4 and 5.
SPOOL 4 is built like:
The size of Spool 4 is estimated with low confidence to be 150,205,354 rows.
SPOOL 5 is built like:
The size of Spool 5 is estimated with high confidence to be 2,677,836 rows.
How to improve confidence level in SPOOL 6 in the above explain plan.
Could you please let me know best practice tips on built locally on the AMPs SPOOL space?
Appreciate for your help.
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