fix: EXPOSED-373 Close ResultSet before closing Statement to suppress Agroal leak warning

[ivan-gomes]

Description

Summary of the change:

Close ResultSet before closing Statement. Motivation is to suppress "JDBC resource leaked" warning when used with agroal.

Detailed description:
Agroal, a popular javax.sql.DataSource implementation as used by Quarkus and others, issues a "leak report" before automatically closing tracked ResultSets and Statements. If a Statement is closed before related ResultSets are closed it will trigger a leak report - ref.

ex.

2024-09-21 11:14:47,325 WARN  [io.agr.pool] (executor-thread-1) Datasource '<default>': JDBC resources leaked: 4 ResultSet(s) and 0 Statement(s)

This warning occurs on every query with results and can cause developers concern - ref.

The following is a trace of the "leaked" ResultSet being accounted.

addLeakedResultSets:804, ConnectionWrapper (io.agroal.pool.wrapper)
closeTrackedResultSets:72, StatementWrapper (io.agroal.pool.wrapper)
close:84, StatementWrapper (io.agroal.pool.wrapper)
close:72, PreparedStatementWrapper (io.agroal.pool.wrapper)
setHasNext:96, AbstractQuery$ResultIterator (org.jetbrains.exposed.sql)
next:111, AbstractQuery$ResultIterator (org.jetbrains.exposed.sql)
next:91, AbstractQuery$ResultIterator (org.jetbrains.exposed.sql)
next:170, IterableExKt$mapLazy$1$iterator$2 (org.jetbrains.exposed.sql)
firstOrNull:279, CollectionsKt___CollectionsKt (kotlin.collections)
findById:95, EntityClass (org.jetbrains.exposed.dao)
findById:57, EntityClass (org.jetbrains.exposed.dao)
...

---

Type of Change

Please mark the relevant options with an "X":

• Bug fix
• New feature
• Documentation update

Updates/remove existing public API methods:

• Is breaking change

Affected databases:

• MariaDB
• Mysql5
• Mysql8
• Oracle
• Postgres
• SqlServer
• H2
• SQLite

Checklist

• Unit tests are in place
• The build is green (including the Detekt check)
• All public methods affected by my PR has up to date API docs
• Documentation for my change is up to date

---

Related Issues

EXPOSED-373

[bog-walk]

Thanks very much for going ahead and opening this PR @ivan-gomes !

Please also add the same fix to the 2 other query ResultIterators: ReturningStatement and ExplainQuery.

Normally in an attempt to keep improving coverage, I'd also ask for a test, but I'll have to deal with that in the backlog. Based on my tests (using AgroalDataSource from agroal-pool with h2), the leak warnings only start from version 2.3+, which requires at minimum jdk 11 and we have to keep using jdk 8 atm.

Thanks again and, once the changes above are made, this fix should make it into the upcoming release.

[bog-walk]

@ivan-gomes From my tests, I'm also seeing that insert statements that return auto-generated keys may produce a leak.
Please add rs?.close() either after the while block in InsertStatement.processResults() or after processResults() is called in executeInternal().

[ivan-gomes]

Thanks very much for going ahead and opening this PR @ivan-gomes !

Please also add the same fix to the 2 other query ResultIterators: ReturningStatement and ExplainQuery.

Normally in an attempt to keep improving coverage, I'd also ask for a test, but I'll have to deal with that in the backlog. Based on my tests (using AgroalDataSource from agroal-pool with h2), the leak warnings only start from version 2.3+, which requires at minimum jdk 11 and we have to keep using jdk 8 atm.

Thanks again and, once the changes above are made, this fix should make it into the upcoming release.

Done, and checked for any other unhandled occurrences of PreparedStatement.close() - didn't find any but you probably already knew that. :)

@ivan-gomes From my tests, I'm also seeing that insert statements that return auto-generated keys may produce a leak. Please add rs?.close() either after the while block in InsertStatement.processResults() or after processResults() is called in executeInternal().

Done, went with the latter so the assignment and cleanup are colocated.

[bog-walk]

Thanks again for the contribution @ivan-gomes !