chrajeshbabu commented on code in PR #1495:
URL: https://github.com/apache/phoenix/pull/1495#discussion_r957870057
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phoenix-core/src/main/java/org/apache/phoenix/compile/WhereOptimizer.java:
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@@ -308,6 +322,30 @@ public static Expression
pushKeyExpressionsToScan(StatementContext context, Set<
slotSpanArray[cnf.size()] = clipLeftSpan-1;
cnf.add(keyRanges);
}
+
+ // Do not use the skipScanFilter when there is a large IN clause
(for e.g > 50k elements)
+ // Since the generation of point keys for skip scan filter will
blow up the memory usage.
+ // See ScanRanges.getPointKeys(...) where using the various slot
key ranges
+ // to generate point keys will lead to combinatorial explosion.
+ // The following check will ensure the cardinality of generated
point keys
+ // is below the configured max (maxInListSkipScanSize).
+ // We shall force a range scan if the configured max is exceeded.
+ // cnfStartPos => is the start slot of this IN list
+ if (checkMaxSkipScanCardinality) {
Review Comment:
Can this conversion of skip scan to range scan configurable because range
scan on bigger data sets is slow?
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