Re: Patch proposal - parameter to limit amount of FPW because of hint bits per second

Hello, Peter.

>> * Add code to _bt_killitems() that detects if it has generated an FPI,
>> just to set some LP_DEAD bits.
>> * Instead of avoiding the FPI when this happens, proactively call
>> _bt_simpledel_pass() just before _bt_killitems() returns. Accept the
>> immediate cost of setting an LP_DEAD bit, just like today, but avoid
>> repeated FPIs.

> Yes, I am almost sure proactively calling of_bt_simpledel_pass() will
> positively impact the system on many workloads. But also I am almost
> sure it will not change the behavior of the incident I mention -
> because it is not related to multiple checkpoints.

I just realized what it seems to be dangerous approache because of
locking mechanism.
Currently _bt_killitems requires only read lock but _bt_simpledel_pass
required write lock (it ends with _bt_delitems_delete).
It will required to increase locking mode in order to call _bt_simpledel_pass.

Such a change may negatively affect many workloads because of write
lock during scanning - and it is really hard to to prove absence of
regression (have no idea how).

Thanks,
Michail.