Re: DML operations slow down

[Rick James]

To assist in analyzing slow SELECTs, please provide
* SHOW CREATE TABLE tbl\G -- engine, indexes
* SHOW TABLE STATUS LIKE 'tbl'\G -- sizes
* EXPLAIN SELECT ...\G -- clues of inefficiencies
* SHOW VARIABLES LIKE '%buffer%'; -- cache size
and surround them with [ code ] and [ / code ]
How much RAM do you have?

There are many reasons why a DML may slow down. The first few that come to mind:
* The system is busier
* The data has grown
* "Random" indexes
* Missing or inadequate indexes
* Increased number of connections