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0 pointsbeagle311y ago0 comments

The timings they give there can only make sense on a fast SSD or when the database they benchmark on is completely cached.

It's an apples-to-oranges comparison only of MDBM wins significantly against LMDB. If they are comparable in timing, or e.g. MDBM is 20% faster, then it would be an apples-to-apples comparison, MDBM having 20% speed advantage, and LMDB having every other possible advantage (memory safety, ACIDity, ordered retrieval, multiple databases, etc.)

LMDB is truly, incredibly, really marvelous. On 64-bit it comes close to being the end-all-be-all local KV-store. If your databases are not more than a few tens of megs each, the same is true for 32-bit processors as well.

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rakoo11y ago· 2 in thread

> If your databases are not more than a few tens of megs each, the same is true for 32-bit processors as well.

Why is that ? Shouldn't 32-bit processors give you enough space in the range of hundreds of MiB ?

hyc_symas11y ago

Sure. But you only have 2-3GB of usable address space, and if your app has a lot of other variables to work with, there's not much space left over.

I should note that in LMDB 1.0 we'll have dynamic unmapping and remapping, to allow 32-bit machines to work with larger DBs. (There's still a significant performance cost for this. It's only being done to allow folks to use the same code on 32 and 64.)

jetm911y ago

Off-topic: will you have something like networked KV store aka redis. what do you think of Redis or Cassandra?

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justin6611y ago

Yes, I am quite impressed by it as well.

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