Aria Max Table Size for internal on-disk temporary tables
Using MariaDB 5.5.31 (deb file for ubuntu 12.04 amd_64: 5.5.31+maria-1precise).
When a query requires an internal temporary tables, and this tables becomes too large to be kept in ram, the table is moved to disk using Aria engine. If the on-disk .MAD file reaches 4GB, an error occurs:
[ERROR] mysqld: The table '/tmp/#sql_74e_0' is full
How can we change this limit?
In https://kb.askmonty.org/en/aria-max-table-size/ it is recommended to change MAX_ROW, but it only applies for explicitly created temporary tables.
Looking at the code I found this in maria_create():
data_file_length= ((((ulonglong) 1 << ((BLOCK_RECORD_POINTER_SIZE-1) * 8))/2 -1) * maria_block_size);
Which amounts to 4GB with default values (8192 for maria_block_size). I created a new DB with aria-block-size = 32768 (the max value), and it still failed at 4GB. Even if it worked, it would mean the max size is only 16GB, and setting a large block size may have performance penalties.
So what is the proper fix to increase this limit?
With MyISAM as on-disk temporary tables engine the limit seems to be much higher (at least 14GB from experiments).
Answer Answered by Daniel Bartholomew in this comment.
On the maria-discuss list, Monty replied to this question with:
This is a bug. Internal temporary tables should always be able to be 'big enough for any kind of query'. I will fix this ASAP.