Changeset: f1bc4422e342 for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=f1bc4422e342
Modified Files:
        monetdb5/optimizer/opt_mitosis.c
Branch: default
Log Message:

Reduce work unit as more clients join
It turns out that reducing the piece sizes with increasing
number of concurrent clients consistently improves throughput.


diffs (21 lines):

diff --git a/monetdb5/optimizer/opt_mitosis.c b/monetdb5/optimizer/opt_mitosis.c
--- a/monetdb5/optimizer/opt_mitosis.c
+++ b/monetdb5/optimizer/opt_mitosis.c
@@ -117,7 +117,7 @@ OPTmitosisImplementation(Client cntxt, M
         * Experience shows that the pieces should not be too small.
         * If we should limit to |threads| is still an open issue.
         */
-       r = (wrd) (monet_memory / argsize);
+       r = (wrd) (monet_memory / argsize/ MCactiveClients());
        /* if data exceeds memory size,
         * i.e., (rowcnt*argsize > monet_memory),
         * i.e., (rowcnt > monet_memory/argsize = r) */
@@ -128,7 +128,7 @@ OPTmitosisImplementation(Client cntxt, M
                 * i.e., (rowcnt/pieces <= r/threads),
                 * i.e., (pieces => rowcnt/(r/threads))
                 * (assuming that (r > threads*MINPARTCNT)) */
-               pieces = (int) (rowcnt / (r / threads)) + 1;
+               pieces = (int) (rowcnt / (r / threads/ MCactiveClients())) + 1;
        } else if (rowcnt > MINPARTCNT) {
        /* exploit parallelism, but ensure minimal partition size to
         * limit overhead */
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