Modify a SELECT Query on ISU DB tables to improve performance

Question

Hi Experts,
I have a SELECT query in a Program which is hitting 6 DB tables by means of 5 inner joins.
The outcome is that the program takes an exceptionally long time to execute, the SELECT statement being the main time consumer.
Need your expertise on how to split the Query without affecting functionality -
The Query :
SELECT  fkkvkpgpart eablablbelnr eabladat eablistablart
  FROM eabl
  INNER JOIN eablg  ON eablgablbelnr = eablablbelnr
  INNER JOIN egerh  ON egerhequnr    = eablequnr
  INNER JOIN eastl  ON eastllogiknr  = egerhlogiknr
  INNER JOIN ever   ON everanlage    = eastlanlage
  INNER JOIN fkkvkp ON fkkvkpvkont   = evervkonto
  INTO TABLE itab
WHERE eabl~adat GT [date which is (sy-datum - 3 years)]
Thanks in advance,
PD

Answer 1

Hi Prajakt
There are a couple of issues with the code provided by Aviansh:
1) Higher Memory consumption by extensive use of internal tables (possible shortdump TSV_NEW_PAGE_ALLOC_FAILED)
2) In many instances multiple SELECT ... FOR ALL ENTRIES... are not faster than a single JOIN statement
3) In the given code the timeslices tables are limited to records active of today, which is not the same as your select (taking into account that you select for the last three years you probably want historical meter/installation relationships as well*)
4) Use of sorted/hashed internal tables instead of standard ones could also improve the runtime (in case you stick to all the internal tables)
Did you create an index on EABL including columns MANDT, ADAT?
Did you check the execution plan of your original JOIN Select statement?
Yep
Jürgen
You should review your selection, because you probably want business partner that was linked to the meter reading at the time of ADAT, while your select doesn't take the specific Contract / Device Installation of the time of ADAT into account.
Example your meter reading is from 16.02.2010
Meter 00001 was in Installation 3000001 between 01.02.2010 and 23.08.2010
Meter 00002 was in Installation 3000001 between 24.08.2010 and 31.12.9999
Installation 3000001 was linked to Account 4000001 between 01.01.2010 and 23.01.2011
Installation 3000001 was linked to Account 4000002 between 24.01.2010 and 31.12.9999
This means with your select returns four lines and you probably want only one.
To achieve that you have to limit all timeslices to the date of EABL-ADAT (selects from EGERH, EASTL, EVER).
Update:
Coming back to point one and the memory consumption:
What are you planning to do with the output of the select statment?
Did you get a shortdump TSV_NEW_PAGE_ALLOC_FAILED with three years meter reading history?
Or did you never run on production like volumes yet?
Dependent on this you might want to redesign your program anyway.
Edited by: sattlerj on Jun 24, 2011 10:38 AM