Hi, On 14/07/2011 13:08, Bruce Adams wrote:
> Having done some experimentation with DTL I am not convinced that OCI is > significantly faster than ODBC. > The evidence seems to suggest similar performance, at least over a network > connection. ODBC too has support > for bulk fetch and bulk insert. My suggestion is that the machinery should be > hidden by the library. > In DTL, for example, I can write > > > bulk_fetch_helper(view.begin(), BATCH_SIZE, > std::ostream_iterator<MyRowData>(std::cout, "\n")); > > The only hint of a vector the is in the batch size parameter itself. And I would suspect that there is no vector, only prefetch of complete rows. If this is true (which I cannot fully confirm), then this comparison is not complete as prefetch is different from bulk fetch. Prefetch means that many rows will be transmitted to the client in anticipation of further consumption, while bulk is based on filling memory arrays in the client process. That is, bulk does not work with rows, it works with columns instead. The vector is instantiated by the client in order to receive that column and the advantage of doing it is in less frequent data copying (the data is injected directly into client target buffer instead of some implicit and intermediary space). As already said, this is my speculation, but I would expect them to work differently, in which case a bulk fetch done with OCI might have some performance advantages over row prefetch as done by ODBC. I have no idea how big this advantage should be. Regards, -- Maciej Sobczak * www.msobczak.com * www.inspirel.com ------------------------------------------------------------------------------ Storage Efficiency Calculator This modeling tool is based on patent-pending intellectual property that has been used successfully in hundreds of IBM storage optimization engage- ments, worldwide. Store less, Store more with what you own, Move data to the right place. Try It Now! http://www.accelacomm.com/jaw/sfnl/114/51427378/ _______________________________________________ Soci-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/soci-users
