hi Folks, show engine RocksDB status shows these values for bloom filter related counters: rocksdb.bloom.filter.useful COUNT : 0 rocksdb.bloom.filter.full.positive COUNT : 192 rocksdb.bloom.filter.full.true.positive COUNT : 192 rocksdb.bloom.filter.prefix.checked COUNT : 0 rocksdb.bloom.filter.p…

We have 2 cases. In one case the first column is 8 bytes only. In other case it can be longer than 8 bytes. However, regardless of whether it is exactly 8 bytes or longer, the rocksdb.bloom.filter.prefix.* counters should not be at 0, right? In either case, at least some non-zero values should be th…

I would assume they shouldn’t be 0 but while I know exactly when some InnoDB counters are updated, in MyRocks I far less sure. Basic question… was the bloomfilter setting added after the table was created? If not, you should try to manually compact it. The only production system I have access to …

I see. Thanks for your responses, but even after a few days we did not see the counters change though lot of compactions were happening. So we think either my config settings are not complete, OR there is some bug causing prefix bloom to be not used.

Bloom filter not being used in MyRocks

MySQL & MariaDB Percona Server for MySQL 8.0

yves.trudeau July 24, 2020, 7:19am 2

Hi, How large are the first columns? There is a 4 bytes index_id part in the prefix so this means only 8 bytes are left for the PK.

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Bloom filter not being used in MyRocks

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