2015-09-01 17:20 GMT+02:00 Shulgin, Oleksandr <oleksandr.shul...@zalando.de> :
> I'm not familiar with the shared memory handling, but could we not >>> allocate just enough shared memory to fit the data we're going to write >>> instead of the fixed 8k? It's not that we cannot know the length of the >>> resulting plan text in advance. >>> >> >> the shared memory cannot be reused - (released) :(, so allocating enough >> memory is not effective. More - in this moment it has not sense. Shared >> memory queue can do almost all work. >> > > A-ha, I've discovered the shared memory message queue facility and I see > how we can use it. > > But do we really need the slots mechanism? Would it not be OK to just let > the LWLock do the sequencing of concurrent requests? Given that we only > going to use one message queue per cluster, there's not much concurrency > you can gain by introducing slots I believe. > I afraid of problems on production. When you have a queue related to any process, then all problems should be off after end of processes. One message queue per cluster needs restart cluster when some pathological problems are - and you cannot restart cluster in production week, sometimes weeks. The slots are more robust. Pavel > > -- > Alex > >
