drill-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From paul-rogers <...@git.apache.org>
Subject [GitHub] drill pull request #761: DRILL-5284: Roll-up of final fixes for managed sort
Date Tue, 28 Feb 2017 00:06:45 GMT
Github user paul-rogers commented on a diff in the pull request:

    --- Diff: exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/xsort/managed/ExternalSortBatch.java
    @@ -392,22 +448,31 @@ private void configure(DrillConfig config) {
         // Set too large and the ratio between memory and input data sizes becomes
         // small. Set too small and disk seek times dominate performance.
    -    spillBatchSize = config.getBytes(ExecConstants.EXTERNAL_SORT_SPILL_BATCH_SIZE);
    -    spillBatchSize = Math.max(spillBatchSize, MIN_SPILL_BATCH_SIZE);
    +    preferredSpillBatchSize = config.getBytes(ExecConstants.EXTERNAL_SORT_SPILL_BATCH_SIZE);
    +    // In low memory, use no more than 1/4 of memory for each spill batch. Ensures we
    +    // can merge.
    +    preferredSpillBatchSize = Math.min(preferredSpillBatchSize, memoryLimit / 4);
    +    // But, the spill batch should be above some minimum size to prevent complete
    +    // thrashing.
    +    preferredSpillBatchSize = Math.max(preferredSpillBatchSize, MIN_SPILL_BATCH_SIZE);
    --- End diff --
    Done later when we tally up memory needs and compare it to available memory. We issue
an error log message if memory overflow is likely. This way, when a query fails, we can look
at the log to see that we knew it would fail due to low memory limits.

If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastructure@apache.org or file a JIRA ticket
with INFRA.

View raw message