Some new mnesia benchmarking results

[Sean Hinde]

Hi all,

I just spent some time benchmarking mnesia for huge disk_copies tables with
the latest versions. Measurements on a SPARC 400MHz with Veritas FS.

Create a table with 1 million rows:
R7B-1 with mnesia-3.10.0  310 secs
R8B   with mnesia-4.0     315 secs
R8B with 10 threads       270 secs

Beam process size afterwards
R7B-1                     167M
R8B                       160M
R8B threads               158M

Stop mnesia
R7B-1 with mnesia-3.10.0  155 secs (and whole node is blocked)
R8B   with mnesia-4.1     3.7 secs
R8B threads               15 secs

Start mnesia and wait for 1M row table to be available
R7B-1                     25 to 50 secs
R8B                       30 secs
R8B threads               56 secs

Subsequent stop of mnesia
R7B-1                     1.9 secs
R8B                       12 secs
R8B threads               25 secs

Start up mnesia after CTRL-C CTRL-C stopping node which is writing as fast
as possible. (Noting disk log repair of DCL file messages on startup).
R7B-1                     40 secs maximum.
R8B                       40 secs
R8B threads               61 secs

Apart from quite a lot of variability in timer:tc results it would appear
that the old behaviour of mnesia where it could potentially take hours to
rebuild tables from badly closed dets tables has been completely cured.

Perhaps someone could confirm that this is always the case and I have not
just been lucky in the timing of my node kills!

I wonder also if anyone knows of any other reasons not to use mnesia for
large databases now?

Very impressive.

Sean



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