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Re: Select count very slow
Posted by: Peter Brawley
Date: May 23, 2017 08:04PM

> do indexes pose risks on performances?

They improve query performance where they can be used. They can slow down Inserts & Updates.

> could it be fatal if not uses correctly?

?! I never heard of anything or anybody dying from an index.

> how could I know If I do wrong or not on my index add choice?

Much to read, eg https://www.slideshare.net/myxplain/mysql-indexing-best-practices-for-mysql

> should I add more indexes depending on other queries I do in record table?

If there are queries on the table that are underperforming, probably.

> how do you find my record table structure and volume of data? is it normal?

> `id` bigint

Really, you expect 9,223,372,036,854,775,807 rows? Int unsigned would give you 4.3 billion, wouldn't that be enough?

> `details` longtext,

You need 4.3 billion text bytes per row?

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