[389-users] Multi-Theading writes to the same 389 Master Server

[David Boreham]

On 8/21/2013 9:46 AM, Ludwig Krispenz wrote:
> we don't have dedicated threads for read or write operations, in 
> theory writes should not block reads, but if the write threads queue 
> up for the backend lock there might be no threads available to do the 
> reads

I wasn't taking about threads. It is not true that writes can't block 
reads. You might say that /typically /writes won't block reads. However 
there are several reasons (including the one I gave -- the read wants 
I/O that ends up delayed behind I/O ops initiated by writes) why reads 
can be blocked by concurrent write activity. As Rich mentioned also, a 
write txn can acquire exclusive locks on DB pages that the read 
subsequently touches.


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