When using SQL_CALC_FOUND_ROWS combined with a LIMIT and an ORDER BY. Does MySQL stop ordering after the LIMIT is reached? Or are all results ordered by MySQL while getting the SQL_CALC_FOUND_ROWS?
If this is the case it probably is faster to do a SELECT COUNT(*) instead…without an ORDER BY.
When MySQL (regular INNER??) JOINs two tables… Does it first do a SELECT on table1 and a SELECT on table2 and then combine the results? Or does it do a SELECT on table1, join it… and do another select?