HIVE-24350: NullScanOptimizer can lookup emptiness info from stats fo… #1645
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mustafaiman
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rbalamohan
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Nov 10, 2020
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| for (Entry<Path, Collection<String>> entry : candidatePathsToAliases.entrySet()) { |
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Wouldn't this have the same issue for external tables (e.g text?). For
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Are you referring to performance issue? Yes this PR does not change anything for external tables. We cannot rely on statistics for external tables. I have another patch ready (need to test first) that deals with external tables. We'll run listStatus calls in parallel for external tables.
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Thanks for sharing the details. HIVE-24380 is what you are referring to I believe.
| if (pathToPartitionMap == null) { | ||
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| addCandidatePath(candidatePathsToAliases, path, alias); |
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Can be candidatePathsToAliases.computeIfAbsent(path, k -> new ArrayList<>()).add(alias) ?
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…r managed tables Change-Id: I7cf7b8f7738c5660ee1c61bcb0456f1c70efe492
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LGTM pending tests. |
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…r managed tables
Change-Id: I7cf7b8f7738c5660ee1c61bcb0456f1c70efe492
What changes were proposed in this pull request?
Why are the changes needed?
Does this PR introduce any user-facing change?
How was this patch tested?