One thing we were guessing at with Massimo yesterday is, if you store
large blobs as disk data, how much will they consume DataMemory and
IndexMemory (primary key, each "chunk" has a hidden primary key, first 25x bytes
of blob stored in memory...)?
My empirical test showed that about 2% of the total size of blobs is needed for RAM
(25% of that is IndexMemory).
IMHO this is close to negligible, but in many situations not negligible
at all (may have close to TB of disk data -> 20GB of RAM needed for
Also note that this is a minimum figure. If you actually have something
else than the blob (like other indexes) you of course use much more RAM.
The test was:
CREATE TABLE `jpgtest` (
`id` int(11) NOT NULL,
PRIMARY KEY (`id`)