MyISAM queries results too slow,What changes should i make,
if
Ram 16GB
DB 500GB
mysql> SHOW STATUS LIKE 'key%'
+------------------------+-------------+
| Variable_name | Value |
+------------------------+-------------+
| Key_blocks_not_flushed | 0 |
| Key_blocks_unused | 275029 |
| Key_blocks_used | 3316428 |
| Key_read_requests | 11459264178 |
| Key_reads | 3385967 |
| Key_write_requests | 91281692 |
| Key_writes | 27930218 |
+------------------------+-------------+
After subtracting off enough room for the actual sizes of the MEMORY tables and any applications that are running on the same machine, give 10% of the remaining RAM to key_buffer_size to 10% and innodb_buffer_pool_size to 35% of RAM. That should be a good first cut at the main memory users.
The Key_reads / Key_read_requests says that key_buffer_size is big enough. Key_blocks_used * 1024 / key_buffer_size will give you an upper bound on what you need currently.
If you have made any other changes in my.cnf, let's see them.