Including user mailing list.
On Tue, Dec 11, 2012 at 1:52 PM, Gregory Chanan <[EMAIL PROTECTED]>wrote:
> Over in HBASE-7263 there has been some discussion about removing support
> for explicit RowLocks in 0.96. This would involve the following:
> - Remove lockRow/unlockRow functions in HTable and similar
> - Remove constructors for Put/Delete/Increment/Get that take RowLocks
> - functions in HRegion no longer take lockIds (checkAndPut, append,
> increment, etc). This would affect coprocessors that call directly into
> those functions.
> I have a patch in HBASE-7315 with the details.
> This would violate our usual rule of deprecating a feature one release
> before removing. The reasoning is as follows:
> 1) RowLocks are broken
> They are only kept in the memory associated with the region, so on a
> split, region move, RS crash, they just disappear
> 2) 0.96 is special
> Now seems like a good time to clean things up since we've made some
> incompatible changes already (e.g. protobufing) and we could have a cleaner
> client implementation
> 3) RowLocks have been deprecated "in spirit" for awhile
> Here's a post from 2009 cautioning against their use:
> and a more recent example:
> 4) RowLocks are hard to use effectively
> Clients can deadlock or starve themselves, either by forgetting to release
> the RowLocks or by starving other non-contending row operations by
> occupying server handlers stuck waiting to acquire the locks.