dhis2-devs team mailing list archive

[Saptarshi Purkayastha <sunbiz@xxxxxxxxx>]

While trying to look at the data model of dhis2, I was surprised to see that
a table called "datavaluecrosstab" is holding 185 columns (basically the
number of data elements).

A cross tabulated query must have created this pivoted, denormalized output,
but why is it still existing in the database?? Basically the cross tabulated
table should have been a temporary table generated by a query on data mart
processing and should have been dropped when the query processing is done.
Either that, or we should use multiple threads to process different parts of
the data marts tree...

Is this a bug?? Or do we have some explanation why this table is still in
the database?? Or is it a point where we can optimize code??

Another observation is that we have a few tables that are using MyISAM
Engine and most others are InnoDB Engine. I don't see why we are using
MyISAM for only a few tables. If we are thinking that MyISAM will increase
performance, then we are following a myth that has been dismissed many times
when using latest versions of MySQL.
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Regards,
Saptarshi PURKAYASTHA
Director R & D, HISP India
Health Information Systems Programme

My Tech Blog:  http://sunnytalkstech.blogspot.com
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