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Performance degradation after drop table




Hello list,

I come here with a case I can say very strange.

I explain, we have a db server with mysql version 5.5.49 on debian 
jessie. Some
days ago, our workflow allowed us to purge a large table from one of our 
db
servers. By large I mean a table which had 350GB in size.

To purge that table, I displayed the table configuration (show create 
table
tblname), then dropped that table and recreated it with the informations 
from
the show create table command. At this point all was ok.

A colleague of mine reported me, 3 days after that purge, that his app's 
jobs are
taking longer to execute compared to before the purge operation. At 
least, the
job's execution time is now, from 1h to 2 hours longer. And once, the 
time was
longer than 2h.
What does the job do ? It writes the same data to 2 tables. On one of 
the tables,
entries older than 2 months are deleted at the end of jobs activity, on 
the other
table these entries are not deleted. This is the table I purged.

I can't seen any logical explanation to that behaviour, and that's 
making me
crazy. I mean, he have now less data, less indexes, less searching, so I 
can't
explain how is it possible.

I'm not an mysql expert, and maybe there is something I don't have as a 
logic.
So I would be grateful, if someone had an explanation for me. Any advice 
is also
welcome to futher debug what is hapening.

Thanks for reading,
K.

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