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Message Posted: Thu, 08 Nov 2012 @ 10:25:36 GMT


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Subj:		JDBC Parameterized Query -- Cache hit Ratio

From:		Anomy Anom

< -- Anonymously Posted: Thursday, November 08, 2012 01:07 -- >

TD13.1 6680
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Background

- now we do rush tests of JDBC tactical queries and ODBC DSS queries to teradata.

- for 10mins

- tactical queries

(typeA) 120 kinds of parameterized tactical queries(about 1000 queries/sec) - (PI select, non-PI select, PI update)

(typeB) 900 kinds of non-parameterized tactical queries(about 1000 queries/sec)

(typeC) 100 kinds of non-parameterized DSS queries(about 1000 queries/sec)

-SLG(service level goal)

(typeA) 1sec

(typeB) 1sec

(typeC) no specific slg

PROBLEM&QUESTION

PI select

SLG OK

NON-PI select

some of queries do not satisfy SLG.

These queries' cache hit ratio (qrylog cache flag=T) about 85%.

If the cache hit ratio is nearly 100%, SLG will be satisfied.

For example, in the rush test,

for three minitues, cache ratio continues 100%.

after 1 minutes, cache ratio is about 0%.

after that, cache ratio continues 100%.

Are there any method to maintain high cache ratio during the rush test?


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