Fix 0-Task Plans in Single-Shard Router When Updating a Local Table with Reference Table in Subquery #7897
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Codecov ReportAll modified and coverable lines are covered by tests ✅
Additional details and impacted files@@ Coverage Diff @@
## release-13.0 #7897 +/- ##
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- Coverage 89.48% 89.46% -0.02%
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Files 276 276
Lines 60063 60009 -54
Branches 7524 7516 -8
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- Hits 53747 53687 -60
- Misses 4166 4173 +7
+ Partials 2150 2149 -1 |
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…for clarity and update related documentation
…f local and reference tables
…dling of local and reference tables
…nting DELETE and MERGE operations to validate reference table handling
…ns in issue 7891 tests
…sue 7891 tests for clarity
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This PR fixes an issue #7891 in the Citus planner where an
UPDATEon a local table with a subquery referencing a reference table could produce a 0-task plan. Historically, the planner sometimes failed to detect that both the target and referenced tables were effectively “local,” assigningINVALID_SHARD_IDand yielding a no-op plan.Root Cause
PlanRouterQuery), we relied onshardIdto determine whether a query should be routed to a single shard.shardId == INVALID_SHARD_ID, but we also had not marked the query as a “local table modification,” the code path would produce zero tasks.Changes
Enhanced Local Table Detection
IsLocalTableModificationand related checks to consider both local and reference tables as “local” for planning, preventing the 0-task scenario.ContainsOnlyLocalOrReferenceTablesto return true if there are no fully distributed tables in the query.Added Regress Test
issue_7891.sql) which reproduces the scenario.