I filed HBASE-6522. It is a trivial change to make locks and leases available to coprocessors. So checkAndSet type operations can then be implemented via coprocessor endpoints: lock row, check, fail or update, unlock row.
Since the patch is so simple I'll commit that soon (to 0.94.2 and 0.96) -- Lars ________________________________ From: lars hofhansl <[email protected]> To: "[email protected]" <[email protected]> Sent: Tuesday, August 7, 2012 8:55 AM Subject: Re: CheckAndAppend Feature There is no such functionality currently, and there is no good way to simulate that. Currently that cannot even be done with a coprocessor endpoint, because region coprocessors have no way to create a region lock (just checked the code). (That is something we have to change I think - I will create an issue once the Jira system is back from the walk in the park). -- Lars ----- Original Message ----- From: Jerry Lam <[email protected]> To: user <[email protected]> Cc: Sent: Tuesday, August 7, 2012 8:22 AM Subject: CheckAndAppend Feature Hi HBase community: I checked the HTable API, it has checkAndPut and checkAndDelete but I'm looking for checkAndAppend. Is there a way to simulate similarly? For instance, I want to check the last 32 bytes of a value (let assume that it has 128 bytes in total) in a column before appending atomically some values into it. Thanks! Jerry
