compatibility and bandwidth saving.
Memory issues by caching should not arise, as the used cache will (in our
previously used cases) only cache index fields and max. 200 relation rows.
I tested performance on my machine: By fetching 400kb of data twice via
mysql_fetch_row() -> mysql_data_seek() -> mysql_fetch_row() this was
performed in 0.25 seconds. By fetching it once and caching in a PHP array
via mysql_fetch_row -> foreach this is performed in 0.32 seconds.
With usual data as used in PMA (10kb) I could only detect a performance
change of 0.009 seconds, which is respectable I think.
By not using mysql_data_seek we are later able to use global mysqli
USE_RESULT options to fetch rows singly. I discussed that yesterday with
Rabus, and if there are any objections we can surely discuss that further on
the list.
