Bug #97850 jdbc42preparestatement cause memory leak

• Submitted: 2 Dec 2019 14:57
• Reporter: lao xh
• Status: Open
• Category: Connector / J
• Severity: S3 (Non-critical)
• Version: 5.1.45
• OS: SUSE
• CPU Architecture: Any

[2 Dec 2019 14:57] lao xh

Description:
The method "StatementImpl.executeBatch()" create a "jdbc42preparestatemnent" which it never close when "useCursorFetch" is "true" and those statement create an exception. The statement registers itself with the connection and remains in the "openStatements" list forever.

How to repeat:
Properties props = new Properties();
props.setProperty("useSSL", "false");
props.setProperty("useServerPrepStmts", "true");
props.setProperty("rewriteBatchedStatements", "true");
props.setProperty("useCursorFetch", "true");
props.setProperty("defaultFetchSize", "100");
props.setProperty("user", "root");

Connection conn = (Connection) DriverManager.getConnection(dbUrl, props);props.setProperty("password", "root");

while(true) {
stm = conn.createStatement();
//abnormal SQL
for(;;){
stm.addBatch("INSERT INTO `sakila`.`city1`(`city`,`country_id`)VALUES('guangzhou',9);");}
stm.executeBatch();
}catch(SQLException e) {}finally{
if (stm != null) {stm.close();}
}
}

Suggested fix:
close those jdbc42preparestatement as no exception happened,when no exception happened,jdbc42preparestatement can be closed. jdbc42preparestatement is not created explicitly by a user,so it should be closed by jdbc.