gianm commented on a change in pull request #8209: add mechanism to control
filter optimization in historical query processing
URL: https://github.com/apache/incubator-druid/pull/8209#discussion_r311788696
##########
File path:
processing/src/main/java/org/apache/druid/segment/filter/Filters.java
##########
@@ -651,4 +652,31 @@ private static void generateAllCombinations(
generateAllCombinations(result, andList.subList(1, andList.size()),
nonAndList);
}
}
+
+ /**
+ * This method provides a "standard" implementation of {@link
Filter#shouldUseIndex(BitmapIndexSelector)} which takes
+ * a {@link Filter}, a {@link BitmapIndexSelector}, and {@link FilterTuning}
to determine if:
+ * a) the filter supports bitmap indexes
+ * b) the filter tuning specifies that it should use the index
+ * c) the cardinality of the column is above the minimum threshold and
below the maximum threshold to use the index
+ *
+ * If all these things are true, {@link
org.apache.druid.segment.QueryableIndexStorageAdapter} will utilize the
+ * indexes.
+ */
+ public static boolean shouldUseIndex(
+ Filter filter,
+ BitmapIndexSelector indexSelector,
+ @Nullable FilterTuning filterTuning
+ )
+ {
+ final FilterTuning tuning = filterTuning != null ? filterTuning :
FilterTuning.createDefault(filter, indexSelector);
+ if (filter.supportsBitmapIndex(indexSelector) && tuning.getUseIndex()) {
+ return filter.getRequiredColumns().stream().allMatch(column -> {
+ final int cardinality =
indexSelector.getBitmapIndex(column).getCardinality();
Review comment:
I think of those options the one that seems nicest to me is adding a
sentence like this to Filter's `getRequiredColumns`:
> If `#supportsBitmapIndex` returns true, all columns returned by this
method can be expected to have a bitmap index retrievable via
`BitmapIndexSelector#getBitmapIndex`.
(And/or something equivalent in `supportsBitmapIndex`)
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
With regards,
Apache Git Services
---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscr...@druid.apache.org
For additional commands, e-mail: commits-h...@druid.apache.org
