mysql stored procedure is slower 20 times than standard query

Question

i have 10 tables with same structure except table name.

i have a sp (stored procedure) defined as following:

 select * from table1 where (@param1 IS          


        

Answer 1

I had seen this behavior, but it wasn't related to the character set.

I had a table that held self-referencing hierarchical data (a parent with children, and some children had children of their own, etc.). Since the parent_id had to reference the primary id's (and the column specified a constraint to that effect), I couldn't set the parent id to NULL or 0 (zero) to disassociate a child from a parent, so I simply referenced it to itself.

When I went to run a stored procedure to perform the recursive query to find all children (at all levels) of a particular parent, the query took between 30 & 40 times as long to run. I found that altering the query used by the stored procedure to make sure it excluded the top-level parent record (by specifying WHERE parent_id != id) restored the performance of the query.

The stored procedure I'm using is based on the one shown in: https://stackoverflow.com/questions/27013093/recursive-query-emulation-in-mysql.