Maintain SIFT Index = Yes but no SumIndexFields

girish.joshi · 2008-02-13

I am taking a look at a database where maintain SIFT index property on the key is set to yet, but it has no sum index fields.

This seems really strange to me. Can anyone think of why a setup might be this way?

I don't think it will impact writing performance negatively, but I'm not sure. Any ideas?

ara3n · 2008-02-13

By default the flag is checked, If you don't have any sumindex fields it won't make any difference, No SIFT tables are created.

Think of it being unchecked if there is no sumindexfields.

My guess why it's checked by default is that people would add sumindexfields
but forget to check maintain index and SQL will do sum on actual table causing performance issues in large tables.

kriki · 2008-02-13

ara3n wrote:

My guess why it's checked by default is that people would add sumindexfields
but forget to check maintain index and SQL will do sum on actual table causing performance issues in large tables.

My guess too.
Especially because when you open the indexes the first time (=with a new zup-file), you don't see the properties for SQL, so it is easy to forget to enable the MaintainSIFTIndex.

DenSter · 2008-02-13

You beat me to this Alain, I even deleted my zupfile to check that out

Where that becomes an issue is when a developer removes all SIFT levels but leaves the MaintainSIFTIndex property checked, and yu want to modify other SIFT levels or even disable a SIFT key. Be aware of these properties and use them the right way.

kriki · 2008-02-13

DenSter wrote:

You beat me to this Alain, I even deleted my zupfile to check that out

I just copied a shortcut to a DB and changed the ID-parameter to a non-existing zup-file.

girish.joshi · 2008-02-13

Thanks, gentlemen!

Maintain SIFT Index = Yes but no SumIndexFields

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