Fix Statement leak in Trino JDBC DatabaseMetaData #10632
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findepi
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nineinchnick
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electrum
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client/trino-jdbc/src/main/java/io/trino/jdbc/AbstractTrinoResultSet.java
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client/trino-jdbc/src/main/java/io/trino/jdbc/TrinoDatabaseMetaData.java
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client/trino-jdbc/src/main/java/io/trino/jdbc/TrinoResultSet.java
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client/trino-jdbc/src/main/java/io/trino/jdbc/TrinoResultSet.java
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client/trino-jdbc/src/main/java/io/trino/jdbc/TrinoResultSet.java
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`AsyncIterator.cancel` is idempotent (future cancellation) and `client.close()` is idempotent too (state atomic swap controls that), so this is not a behavioral change, but necessary for further code evolution.
It's somewhat more readable if the mutable state, especially one that needs to be updated with thread-safety in mind, is confined to a class.
Before the change, Trino JDBC's `DatabaseMetaData` implementation (`TrinoDatabaseMetaData`) would create `Statement` objects that are never closed. Since `Connection` (`TrinoConnection`) tracks open statements to be able to close them upon `Connection.close()` (per JDBC requirements), this created a memory leak where `Statement` objects are leaked in `Connection.statements` collection. The commit fixing this, under the condition that `ResultSet` returned from `TrinoDatabaseMetaData` is correctly closed.
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kokosing
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Before the change, Trino JDBC's
DatabaseMetaDataimplementation(
TrinoDatabaseMetaData) would createStatementobjects that arenever closed. Since
Connection(TrinoConnection) tracks openstatements to be able to close them upon
Connection.close()(per JDBCrequirements), this created a memory leak where
Statementobjects areleaked in
Connection.statementscollection.The commit fixing this, under the condition that
ResultSetreturnedfrom
TrinoDatabaseMetaDatais correctly closed.Fixes #10584