Lars H replied to you this afternoon. Please check his reply.
On Thu, Aug 2, 2012 at 8:02 PM, Wei Tan <[email protected]> wrote: > Hi, > > I have a question regarding the correlation between the visible > timestamp of a KV (denoted as ts) and its memstore timestamp (aka, the > write number, denoted as memts). Reading the HRegion.java code it seems > that these two are independently assigned. Let's assume two concurrent > put: (k, v1) and (k, v2) > > > Suppose somehow memts(k,v1) < memts(k, v2) then (k,v1) will be committed > and visible before (k,v2). > If ts(k,v1) < ts(k, v2), then after both KVs commits, (k,v2) becomes the > latest version. > else, if ts(k,v1) > ts(k, v2), then after a "later"(w.r.t. MVCC) KV > commits, it immediately become stale and still not visible. --- Is it a > desirable feature? > > > Am I understanding it correctly, that memts(k,v1) < memts(k, v2) does > not indicate that ts(k,v1) < ts(k, v2), and vice versa? > PS: let's talk about the hbase region server assigned, not user assigned, > visible timestamp. > > Thanks, > > Wei > > > Wei Tan > Research Staff Member > IBM T. J. Watson Research Center > 19 Skyline Dr, Hawthorne, NY 10532 > [email protected]; 914-784-6752
