Known caveats with RT indexes

RT indexes are currently quality feature, but there are still a few known usage quirks. Those quirks are listed in this section.

Default conservative RAM chunk limit (rt_mem_limit) of 32M can lead to poor performance on bigger indexes, you should raise it to 256..1024M if you're planning to index gigabytes.
High DELETE/REPLACE rate can lead to kill-list fragmentation and impact searching performance.
No transaction size limits are currently imposed; too many concurrent INSERT/REPLACE transactions might therefore consume a lot of RAM.
In case of a damaged binlog, recovery will stop on the first damaged transaction, even though it's technically possible to keep looking further for subsequent undamaged transactions, and recover those. This mid-file damage case (due to flaky HDD/CDD/tape?) is supposed to be extremely rare, though.
Multiple INSERTs grouped in a single transaction perform better than equivalent single-row transactions and are recommended for batch loading of data.