[CDash] Duplicate rows in build2test

[Zack Galbreath]

On Thu, May 19, 2016 at 9:40 AM, Matějů Miroslav, Ing. <
Mateju.Miroslav at azd.cz> wrote:

> Hi,
>
>
>
> I am sending a few updates regarding the build2test problem. I copied my
> DB to a virtual machine and performed a few experiments to reduce the size
> of build2test table. I was experimenting with an older backup version with
> the size of 9.3 GiB. (The DB on my production server has 17.5 GiB currently
> while the single table build2test has 11.7 GiB.)
>
>
>
> I tried to remove the duplicates using the method from
> https://stackoverflow.com/a/3312066/711006. First of all, I had to
> convert the table to MyISAM because of an InnoDB bug (
> https://stackoverflow.com/a/8053812/711006). The MyISAM version has about
> one half of the size of InnoDB version.
>
> There were 1.9 million duplicate rows out of 67.6 M and the data size
> decreased slightly from 1.3 GiB to 1.2 GiB while creation of the new unique
> index caused the index grow from 2.3 GiB to 3.2 GiB. I have not tried to
> convert the table back to InnoDB yet but I would expect similar inflation
> of index. So I would not recommend to create the unique index anymore, at
> least until I check it with InnoDB.
>
>
>
> I also found that the column status of type varchar(10) contains just
> three values. Even the command
>
>     SELECT status FROM build2test PROCEDURE ANALYSE()\G
>
> recommended to change the type to
>
>     ENUM('failed','notrun','passed') NOT NULL
>
>
>
> I tried it and the table size decreased from 9.3 GiB to 8.5 GiB reducing
> the size of both data and index, at least for InnoDB. However, the MyISAM
> version grew slightly (from 4.4 GiB to 5 GiB).
>
>
>
> I am going to try more optimization methods if time allows.
>


Thanks for digging into this.  I certainly appreciate it.

Often times I find that you need to run OPTIMIZE TABLE to reclaim disk
space after making big changes to the database.  Consider giving that a try
if you haven't been doing so already.
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