On Tue, Nov 27, 2012 at 1:22 PM, Roshan Punnoose <[email protected]> wrote:
> Thanks! > > The fact that you are using a binary tree behind the scenes makes perfect > sense. Btw, what do you use in the standalone (non native) implementation? > Does it use a TreeMap? > When not using native code, ConcurrentSkipListMap is used. > > > On Tue, Nov 27, 2012 at 12:57 PM, Keith Turner <[email protected]> wrote: > >> >> >> On Tue, Nov 27, 2012 at 12:21 PM, Roshan Punnoose <[email protected]>wrote: >> >>> The <string> would most likely be a fixed set of strings that do not >>> change over time. >>> >>> My question is if it is bad to use a reverse index timestamp in the row >>> id? Will it cause problems with the tablet splitting, compaction, and >>> performance if the data is always being sent to the top of the tablet? If I >>> define a split as everything prefixed with <string>, then the ingest will >>> go to one tablet, but then I add a reverse timestamp in the row, and that >>> would mean I am always copying data to the top of the tablet. Will this >>> cause performance issues? Or is it better to append to a tablet? >>> >> >> I do not think it should matter. Inserts go into a C++ STL map on the >> tablet server if using the nativemap. I think the implementation of that >> is a balanced binary tree. So I do not think inserting at the beginning vs >> the end would make difference. That being said, I do not think I have >> tried this so I do not know if there would be any suprises. I would be >> interested in hearing about your experiences. >> >> >>> >>> >>> On Tue, Nov 27, 2012 at 11:51 AM, Keith Turner <[email protected]> wrote: >>> >>>> >>>> >>>> Keith >>>> >>>> On Tue, Nov 27, 2012 at 10:41 AM, Roshan Punnoose <[email protected]>wrote: >>>> >>>>> I want to have a table where the row will consist of >>>>> "<string>-<reverse index timestamp>". But this means that the data is >>>>> always being prefixed to the beginning of the row (or tablet if the row is >>>>> large). Will this be a problem for compaction or performance? >>>> >>>> >>>> Can you tell me more about what <string> is? For example is it a hash >>>> or does it come from the set "foo1","foo2","foo3". How does it change >>>> over time? I think the answer to your question depends on what <string> >>>> is. >>>> >>>> >>>>> >>>>> I don't know if I heard this correctly, but someone once mentioned >>>>> that making the row id the direct timestamp could cause performance issues >>>>> because data is always going to one tablet, but also because there is >>>>> trouble splitting since it always appends to the tablet. Is this true, is >>>>> it similar to what could happen if I am always prefixing to a tablet? >>>>> >>>> >>>> Yes using a timestamp for a row could cause data from many clients to >>>> always go to the same tablet, which would be bad for performance on a >>>> cluster. >>>> >>>> >>>>> >>>>> Thanks! >>>>> Roshan >>>>> >>>> >>>> >>> >> >
