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How to analyse why a database have DATA#: collision rate high

Former Member
0 Kudos

Hi,

on MaxDB 7.6.6.10 community license, running on Linux 64bit using analyzer I can see follow output:

===== #613        at 2013-07-31 14:52:52

*  I  SQL commands executed: 289821, avg. 960.5 per second

* W1  1 command cache cleanups! 16 commands reloaded, 120 execution plans and 3040 commands deleted

* W3  6641 table scans, selectivity 0.23%: 3605289 rows read, 8141 rows qualified

* W1  DATA61: collision rate 38.86%, 72859 collisions, 1 waits (0%), 187481 accesses on region 112

* W1  DATA64: collision rate 59.33%, 88610 collisions, no waits, 149345 accesses on region 115

* W1  DATA3: collision rate 28.7%, 78293 collisions, no waits, 272814 accesses on region 54

* W1  DATA23: collision rate 34.87%, 56068 collisions, no waits, 160802 accesses on region 74

* W1  DATA43: collision rate 28.5%, 84728 collisions, no waits, 297304 accesses on region 94

* W1  DATA18: collision rate 27.62%, 59965 collisions, no waits, 217098 accesses on region 69

* W1  DATA24: collision rate 52.85%, 81855 collisions, no waits, 154873 accesses on region 75

* W1  DATA2: collision rate 36.78%, 57084 collisions, no waits, 155204 accesses on region 53

* W1  DATA42: collision rate 40.49%, 77149 collisions, no waits, 190546 accesses on region 93

* W1  DATA51: collision rate 33.76%, 69859 collisions, no waits, 206934 accesses on region 102

* W1  DATA7: collision rate 31.11%, 73546 collisions, no waits, 236426 accesses on region 58

* W1  DATA37: collision rate 26.68%, 95941 collisions, no waits, 359565 accesses on region 88

* W1  DATA40: collision rate 38.18%, 51877 collisions, no waits, 135880 accesses on region 91

* W1  DATA25: collision rate 28.15%, 67961 collisions, no waits, 241391 accesses on region 76

*  I  Garbage collector tasks activated 2 times, currently active: 0

*  I  3420 physical reads for user task 550, 14618 commands, application pid 8219

*  I  3376 physical reads for user task 139, 15836 commands, application pid 8219

*  I  CPU utilization: instance MAXDB1: 23.84% (usr: 23.51%, sys: 0.33%), host: 56.62% (usr: 23.84%, sys: 0.99%, wio: 31.79%, idle: 741.39%)

How I can solve these collision rates, there is a way to check what data, table or row exists on these regions? Any better way to analyse this?

Best regards.

Clóvis

Accepted Solutions (1)

Accepted Solutions (1)

yashwanthkumar_kethineed
Active Participant
0 Kudos

Did you check SAP Note: 1423935 (Section 14 & 15)

Also helpfull information in :

http://wiki.sdn.sap.com/wiki/display/MaxDB/SAP+MaxDB+Regions+A+-+D

http://wiki.sdn.sap.com/wiki/display/MaxDB/MaxDB+Database+Analyzer

For the performance analysis tools, you will find an expert session

at: http://maxdb.sap.com/training.

Former Member
0 Kudos

Hi Yashwanth,

I'm use community edition and as I'm not a SAP customer I dont have access to SAP Notes.

I can research for that, but what I want with this question, is to know what more experienced MaxDB users know about this type of issue.

Best regards.


Clóvis

Answers (0)