Aleksandr Efimov has posted comments on this change. ( http://gerrit.cloudera.org:8080/24426 )
Change subject: IMPALA-14601: Support HBO for JoinNode cardinality ...................................................................... Patch Set 35: (1 comment) http://gerrit.cloudera.org:8080/#/c/24426/35/fe/src/main/java/org/apache/impala/planner/AggregationNode.java File fe/src/main/java/org/apache/impala/planner/AggregationNode.java: http://gerrit.cloudera.org:8080/#/c/24426/35/fe/src/main/java/org/apache/impala/planner/AggregationNode.java@839 PS35, Line 839: sb.append("|Preagg:").append(isPreagg_) This hunk renames parts of a key string that already exists: `preagg:` becomes `Preagg:` and `GROUP:` becomes `Group:`. The union key changes the same way (`operands:` to `Operands:`), and the scan key moves its separators. So every HBO entry an older coordinator stored becomes unreachable after an upgrade, not only the join keys this patch adds. The stored key is a hash of the string, so such an entry can only be missed, never read as a new one, and no plan gets a wrong cardinality out of it. With the cache in memory that costs one warm-up. Once a backend outlives the process, as in 24822 and 24824, the entries stay until the TTL expires or eviction removes them. Would you mind a line in the commit message saying that this patch changes the key format? On our side I will add a key format version to the snapshot header in 24824, so a snapshot written by an older build is skipped instead of loaded. -- To view, visit http://gerrit.cloudera.org:8080/24426 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I70b655ae7027d0d9eb8e9fae9ba2e1b7ad9876b4 Gerrit-Change-Number: 24426 Gerrit-PatchSet: 35 Gerrit-Owner: Quanlong Huang <[email protected]> Gerrit-Reviewer: Aleksandr Efimov <[email protected]> Gerrit-Reviewer: Aman Sinha <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Quanlong Huang <[email protected]> Gerrit-Reviewer: Steve Carlin <[email protected]> Gerrit-Comment-Date: Wed, 16 Sep 2026 18:04:36 +0000 Gerrit-HasComments: Yes
