The BLACKHOLE storage engine acts as a “black hole” that accepts data but throws it away and does not store it. Retrievals always return an empty result.
The BLACKHOLE storage engine acts as a “black hole” that accepts data but throws it away and does not store it. Retrievals always return an empty result. When you create a BLACKHOLE table, the server creates a table format file in the database directory. The file begins with the table name and has an .frm extension. There are no other files associated with the table.
The BLACKHOLE storage engine supports all kinds of indexes. That is, you can include index declarations in the table definition.
You can check whether the BLACKHOLE storage engine is available with this statement:
mysql> SHOW VARIABLES LIKE 'have_blackhole_engine';
Uses:
- Verification of dump file syntax.
- Measurement of the overhead from binary logging, by comparing performance using BLACKHOLE with and without binary logging enabled.
- BLACKHOLE is essentially a “no-op” storage engine, so it could be used for finding performance bottlenecks not related to the storage engine itself.
