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Database size growht when migrationg to Sybase IQ

Feb 21, 2017 at 04:40 AM

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Former Member

Hi.. we have current system mostly on DB2, and we need to migrate it to sybase IQ, how we can predict the database size on sybase ? is it will increase ot decrease ?

we did not activate db2 compression

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Former Member
Apr 03, 2017 at 05:50 PM
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The traditional answer is that data loaded in IQ will be equivalent to or less than the RAW data loaded into DB2, which may be 3-10 times less than the data loaded in DB2, when you consider indexing in DB2.

In a simple 1GB TPC-H test I did on IQ16 GA several years ago, the data was fully loaded and indexed in IQ in only 52% of the original raw data size.

As the previous answer states, however, your mileage may vary. You should load the data into IQ to check.

Remember to remove any composite 'covering' indexes in any query and review the rest of the IQ index types. A big difference between IQ and other DBMS engines is that IQ's indexes are actually the storage mechanisms, there can be more than one index per column, and IQ's optimizer will use all indexes to resolve a query. This is unlike other DBMS engines where the optimizer may select a specific index and not use any others.

Chris

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Juan Reyes
Feb 22, 2017 at 10:55 AM
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Hi Muda,

Simple answer, you do a heterogeneous system copy into a Sandbox and find out.

The rest is speculative.

Regards, JP

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Frank-Martin Haas
Dec 04, 2017 at 10:37 AM
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Hi Muda,

yes, it is difficult to provide reliable comparisons about compression rates on different DB plattform. Marketing slides do not help. So you need to test first on a ssandbox to get a feeling.

Regards

Frank

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