Here is the threshold formula of auto merge and this formula is configured in auto_merge_decision_fun under indexserver.ini.
(((DMS>PAL/2000 or DCC>100) and DRC > MRC/100) or (DMR>0.2*MRC and DMR > 0.001)) and (DUC<0 .1="" 0.05="" or="">=DUC)
DMS : Delta memory size [MB]
PAL : Process allocation limit [MB]
DCC : Delta cell count [million] This refers to the current number of cells in the delta storage of the table.
DRC : Delta row count [million] This refers to the current number of rows in the delta storage of the table.
MRC : Main row count [million] This refers to the current number of rows in the main storage of the table.
DMR : Deleted main rows [million] This refers to the number of deleted records not in delta storage, but marked as deleted in main storage. Merging makes sense if there are many deleted rows.
DUC : Delta uncommitted row count [million] This refers to the number of uncommitted rows in the delta storage of the table.
How to Set Parameter - indexserver.ini -> auto_merge_decision_fun
Note : this can find in SAP HANA Administration guide.
If you can match this formular from result of selecting BGRFC_UNIT_TIME from M_CS_TABLES, you will get the idea of auto merge threshold.
Example:
RECORD_COUNT : 7,039
RAW_RECORD_COUNT_IN_DELTA : 30,980
In this case, the contidion of (DMR>0.2*MRC and DMR > 0.001) dose not meet the requirement.
((8,489 - 7,039)>0.2*8,489 and (8,489 - 7,039) > 0.001)
This is why in this case auto merge will not trigger.
Related Topic - Delta Merge in SAP HANA
Related Topic - Delta Merge Issue in SAP HANA
Related Topic - Mergedog in SAP HANA
(((DMS>PAL/2000 or DCC>100) and DRC > MRC/100) or (DMR>0.2*MRC and DMR > 0.001)) and (DUC<0 .1="" 0.05="" or="">=DUC)
DMS : Delta memory size [MB]
PAL : Process allocation limit [MB]
DCC : Delta cell count [million] This refers to the current number of cells in the delta storage of the table.
DRC : Delta row count [million] This refers to the current number of rows in the delta storage of the table.
MRC : Main row count [million] This refers to the current number of rows in the main storage of the table.
DMR : Deleted main rows [million] This refers to the number of deleted records not in delta storage, but marked as deleted in main storage. Merging makes sense if there are many deleted rows.
DUC : Delta uncommitted row count [million] This refers to the number of uncommitted rows in the delta storage of the table.
How to Set Parameter - indexserver.ini -> auto_merge_decision_fun
Note : this can find in SAP HANA Administration guide.
If you can match this formular from result of selecting BGRFC_UNIT_TIME from M_CS_TABLES, you will get the idea of auto merge threshold.
Example:
RECORD_COUNT : 7,039
RAW_RECORD_COUNT_IN_DELTA : 30,980
In this case, the contidion of (DMR>0.2*MRC and DMR > 0.001) dose not meet the requirement.
((8,489 - 7,039)>0.2*8,489 and (8,489 - 7,039) > 0.001)
This is why in this case auto merge will not trigger.
Related Topic - Delta Merge in SAP HANA
Related Topic - Delta Merge Issue in SAP HANA
Related Topic - Mergedog in SAP HANA
6 comments:
Hello Shailendra Srivastava,
The blog really helpful.
I have issue like, in my systems few tables are not getting auto merge evnthough the auto merge is on.
I felt the auto_merge_func threshold is not meeting in order to carry out the merge.
Can please explain briefly (((DMS>PAL/2000 or DCC>100) and DRC > MRC/100) or (DMR>0.2*MRC and DMR > 0.001)) and (DUC<0 .1="" 0.05="" or="">=DUC this with example.
Awaiting for your reply.
Thank you.
Regards,
Poornima
which value is 8,489 in example?
Hi Deepa,
Thanks for your comment.
Can you please share DB Detail like Version & Release & Threshold value for Mergedog.
Thank you.
Regard's
Shailendra
Hello Shsliendra,
My DB version is: 1.00.097.03.1443520413
Auto_merge_func set to value: (((DMS>PAL/2000 or DCC>100) and DRC > MRC/100) or (DMR>0.2*MRC and DMR > 0.001)) and (DUC<0.1 or 0.05*DRC>=DUC)
Regards,
Poornima
Hello,
Can you explain my auto_merge_func with example?
Regards,
Poornima
Where to find values set for these parameters?
DMS : Delta memory size [MB]
PAL : Process allocation limit [MB]
DCC : Delta cell count [million] This refers to the current number of cells in the delta storage of the table.
DRC : Delta row count [million] This refers to the current number of rows in the delta storage of the table.
MRC : Main row count [million] This refers to the current number of rows in the main storage of the table.
DMR : Deleted main rows [million] This refers to the number of deleted records not in delta storage, but marked as deleted in main storage. Merging makes sense if there are many deleted rows.
DUC : Delta uncommitted row count [million] This refers to the number of uncommitted rows in the delta storage of the table.
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