speed up temporary table inserts

Temporary tables use the MyISAM storage engine by default (in fact, you can specify any storage engine for a temporary table, a fact that few people realize).

You can thusly speed up bulk inserts into a temporary table just like any other table. For the case of default MyISAM temporary tables, I was able to approximately halve the insert execution time of a big bulk insert by surrounding the insert operations with alter table index_builder disable keys and alter table index_builder enable keys.

Another tip for temporary tables is if the temporary table is reasonably small, you can specify engine=Memory to create the table in memory rather than MyISAM, just be aware of the implications of memory/heap tables.