Philippe,
I read two potentially important things from your statistics:

1) You keep (at least) one transaction open.

> Oldest active 2
> Next transaction 231

The gap between oldest active and next transaction ought to be small. Since
your database is pretty new the gap isn't very big yet, but you have to
commit occationally. Just something to be aware of.

2) Most of your indexes contain lots of duplicates

> Depth: 2, leaf buckets: 367, nodes: 487329
> Average data length: 0.00, total dup: 487327, max dup: 32730

This will make updates and deletes slow. Either drop such indexes or add
the primary key to the end of the index.

HTH,

Set

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