I have a 10 million record table that contain 3 blobs.
We do not search on these blobs. Instead we use them to do calculations using custom udf functions that do summarization on the blobs.
Anyway during large queries we see the ‘copying to tmp’ when we do some of these large queries. However when I do a show status I get this:
mysql> show status like ‘%tmp%’;
±------------------------±------+
| Variable_name | Value |
±------------------------±------+
| Created_tmp_disk_tables | 0 |
| Created_tmp_files | 5 |
| Created_tmp_tables | 1 |
But I thought that blobs would force the use of tmp_disk_tables?
Would performance benefit if I used memory disks as my tmpdir?