Fix empty join conditions query failure

[SemionPar]

Description

Fix "joinConditions is empty" error.

Additional context and related issues

Bisected to 91a29a7

SELECT a.c_num FROM left a LEFT JOIN right b ON DATE '2025-03-19' = b.c_date;

Query of this shape results in

Caused by: com.google.common.base.VerifyException: joinConditions is empty
	at com.google.common.base.Verify.verify(Verify.java:126)
	at io.trino.plugin.jdbc.DefaultQueryBuilder.prepareJoinQuery(DefaultQueryBuilder.java:126)
	at io.trino.plugin.jdbc.BaseJdbcClient.implementJoin(BaseJdbcClient.java:537)
	at io.trino.plugin.postgresql.PostgreSqlClient.lambda$implementJoin$13(PostgreSqlClient.java:1074)
	at io.trino.plugin.jdbc.JdbcJoinPushdownUtil.implementJoinCostAware(JdbcJoinPushdownUtil.java:46)
	at io.trino.plugin.postgresql.PostgreSqlClient.implementJoin(PostgreSqlClient.java:1068)
	at io.trino.plugin.jdbc.ForwardingJdbcClient.implementJoin(ForwardingJdbcClient.java:220)
	at io.trino.plugin.jdbc.jmx.StatisticsAwareJdbcClient.lambda$implementJoin$20(StatisticsAwareJdbcClient.java:239)
	at io.trino.plugin.jdbc.jmx.JdbcApiStats.wrap(JdbcApiStats.java:34)
	at io.trino.plugin.jdbc.jmx.StatisticsAwareJdbcClient.implementJoin(StatisticsAwareJdbcClient.java:239)
	at io.trino.plugin.jdbc.CachingJdbcClient.implementJoin(CachingJdbcClient.java:293)
	at io.trino.plugin.jdbc.CachingJdbcClient.implementJoin(CachingJdbcClient.java:293)
	at io.trino.plugin.jdbc.DefaultJdbcMetadata.applyJoin(DefaultJdbcMetadata.java:497)
	at io.trino.plugin.base.classloader.ClassLoaderSafeConnectorMetadata.applyJoin(ClassLoaderSafeConnectorMetadata.java:1042)
	at io.trino.tracing.TracingConnectorMetadata.applyJoin(TracingConnectorMetadata.java:1206)
	at io.trino.metadata.MetadataManager.applyJoin(MetadataManager.java:1957)
	at io.trino.tracing.TracingMetadata.applyJoin(TracingMetadata.java:988)
	at io.trino.sql.planner.iterative.rule.PushJoinIntoTableScan.apply(PushJoinIntoTableScan.java:149)
	at io.trino.sql.planner.iterative.rule.PushJoinIntoTableScan.apply(PushJoinIntoTableScan.java:68)
	at io.trino.sql.planner.iterative.IterativeOptimizer.transform(IterativeOptimizer.java:209)
	at io.trino.sql.planner.iterative.IterativeOptimizer.exploreNode(IterativeOptimizer.java:176)
	at io.trino.sql.planner.iterative.IterativeOptimizer.exploreGroup(IterativeOptimizer.java:139)
	at io.trino.sql.planner.iterative.IterativeOptimizer.exploreChildren(IterativeOptimizer.java:259)
	at io.trino.sql.planner.iterative.IterativeOptimizer.exploreGroup(IterativeOptimizer.java:141)
	at io.trino.sql.planner.iterative.IterativeOptimizer.optimize(IterativeOptimizer.java:123)
	at io.trino.sql.planner.LogicalPlanner.runOptimizer(LogicalPlanner.java:309)
	at io.trino.sql.planner.LogicalPlanner.plan(LogicalPlanner.java:270)
	at io.trino.sql.planner.LogicalPlanner.plan(LogicalPlanner.java:239)
	at io.trino.sql.planner.LogicalPlanner.plan(LogicalPlanner.java:234)
	at io.trino.execution.SqlQueryExecution.doPlanQuery(SqlQueryExecution.java:486)
	at io.trino.execution.SqlQueryExecution.planQuery(SqlQueryExecution.java:466)
	at io.trino.execution.SqlQueryExecution.start(SqlQueryExecution.java:404)
	at io.trino.execution.SqlQueryManager.createQuery(SqlQueryManager.java:264)
	at io.trino.dispatcher.LocalDispatchQuery.startExecution(LocalDispatchQuery.java:145)
	at io.trino.dispatcher.LocalDispatchQuery.lambda$waitForMinimumWorkers$2(LocalDispatchQuery.java:129)
	at io.airlift.concurrent.MoreFutures.lambda$addSuccessCallback$12(MoreFutures.java:568)
	at io.airlift.concurrent.MoreFutures$3.onSuccess(MoreFutures.java:543)
	at com.google.common.util.concurrent.Futures$CallbackListener.run(Futures.java:1133)
	at io.trino.$gen.Trino_testversion____20250430_152414_75.run(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
	at java.base/java.lang.Thread.run(Thread.java:1583)

Joins with effectively empty filters should not be pushed down.

Release notes

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## Section
* Fix `joinConditions is empty` error happening for certain query shapes.

[SemionPar]

Oracle ci failure is unrelated, PTAL @Praveen2112

[Praveen2112]

% nit

[SemionPar]

Fixed the nit and rebased - @Praveen2112 please merge once CI is done

[Praveen2112]

I have one question on what’s special for LEFT and FULL join

[Praveen2112]

Any specific reason on pushdown is applied for LEFT or FULL join ?

[SemionPar]

This 'decorative' join query shape looks slightly different for different join operators, e.g. the join filter is retained in the join node for the LEFT JOIN:

SELECT n.name FROM postgresql.tpch.nation n LEFT JOIN postgresql.tpch.orders o ON n.regionkey = 1;

LeftJoin[filter = (regionkey = bigint '1'), distribution = REPLICATED]
│   Layout: [name:varchar(25)]
│   Distribution: REPLICATED
├─ TableScan[table = postgresql:tpch.nation tpch.tpch.nation columns=[name:varchar(25):varchar, regionkey:bigint:int8]]
│      Layout: [name:varchar(25), regionkey:bigint]
└─ LocalExchange[partitioning = SINGLE]
  └─ RemoteSource[sourceFragmentIds = [1]]

Fragment 1 [SOURCE]
    Output partitioning: BROADCAST []
    TableScan[table = postgresql:tpch.orders tpch.tpch.orders columns=[]]
        Layout: []

On the other hand, for RIGHT JOIN, condition is pushed down into constraint on the scan:

SELECT n.name FROM postgresql.tpch.nation n RIGHT JOIN postgresql.tpch.orders o ON n.regionkey = 1

RightJoin[distribution = PARTITIONED]
│   Layout: [name:varchar(25)]
│   Distribution: PARTITIONED
├─ RemoteSource[sourceFragmentIds = [1]]
│      Layout: [name:varchar(25)]
└─ LocalExchange[partitioning = SINGLE]
  │   Layout: []
  └─ RemoteSource[sourceFragmentIds = [2]]
         Layout: []

Fragment 1 [SOURCE]
    Output partitioning: HASH []
    TableScan[table = postgresql:tpch.nation tpch.tpch.nation constraint on [regionkey] columns=[name:varchar(25):varchar]]
        Layout: [name:varchar(25)]

Fragment 2 [SOURCE]
    Output partitioning: HASH []
    TableScan[table = postgresql:tpch.orders tpch.tpch.orders columns=[]]
        Layout: []

There is actually no join condition to push down, so applyJoin returns empty-handed.

[Praveen2112]

@SemionPar Can you please update the release notes.