[
https://issues.apache.org/jira/browse/FLINK-16708?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17064202#comment-17064202
]
tangshangwen commented on FLINK-16708:
--------------------------------------
On the first execution, connection.getAutoCommit () throws PSQLException: This
connection has been closed, at which time the batchStatements have been cleared
{code:java}
// PgStatement.java
private BatchResultHandler internalExecuteBatch() throws SQLException {
// Construct query/parameter arrays.
transformQueriesAndParameters();
// Empty arrays should be passed to toArray
// see http://shipilev.net/blog/2016/arrays-wisdom-ancients/
Query[] queries = batchStatements.toArray(new Query[0]);
ParameterList[] parameterLists = batchParameters.toArray(new
ParameterList[0]);
batchStatements.clear();
batchParameters.clear();
...
if (connection.getAutoCommit()) {
flags |= QueryExecutor.QUERY_SUPPRESS_BEGIN;
}
...
}{code}
When executeBatch method is executed for the second time, batchStatements is
isEmpty and returned without throwing any exception
{code:java}
// PgStatement.java
public int[] executeBatch() throws SQLException {
checkClosed();
closeForNextExecution();
if (batchStatements == null || batchStatements.isEmpty()) {
return new int[0];
}
return internalExecuteBatch().getUpdateCount();
}
{code}
> When a JDBC connection has been closed, the retry policy of the
> JDBCUpsertOutputFormat cannot take effect and may result in data loss
> -------------------------------------------------------------------------------------------------------------------------------------
>
> Key: FLINK-16708
> URL: https://issues.apache.org/jira/browse/FLINK-16708
> Project: Flink
> Issue Type: Bug
> Components: Connectors / JDBC
> Affects Versions: 1.10.0
> Reporter: tangshangwen
> Priority: Major
>
> In our test environment, I used the tcpkill command to simulate a scenario
> where the postgresql connection was closed. I found that the retry strategy
> of the flush method did not take effect, and when it retried the second time,
> it could not recognize that the connection had been closed because Before the
> first check whether the connection is closed, the batchStatements of
> PgStatement have been cleared, which causes the second execution to check
> that the batchStatements are empty and return normally.
> {code:java}
> 2020-03-20 21:16:18.246 [jdbc-upsert-output-format-thread-1] ERROR
> org.apache.flink.api.java.io.jdbc.JDBCUpsertOutputFormat - JDBC executeBatch
> error, retry times = 1
> org.postgresql.util.PSQLException: This connection has been closed.
> at
> org.postgresql.jdbc.PgConnection.checkClosed(PgConnection.java:857)
> at
> org.postgresql.jdbc.PgConnection.getAutoCommit(PgConnection.java:817)
> at
> org.postgresql.jdbc.PgStatement.internalExecuteBatch(PgStatement.java:813)
> at org.postgresql.jdbc.PgStatement.executeBatch(PgStatement.java:873)
> at
> org.postgresql.jdbc.PgPreparedStatement.executeBatch(PgPreparedStatement.java:1569)
> at
> org.apache.flink.api.java.io.jdbc.writer.AppendOnlyWriter.executeBatch(AppendOnlyWriter.java:62)
> at
> org.apache.flink.api.java.io.jdbc.JDBCUpsertOutputFormat.flush(JDBCUpsertOutputFormat.java:159)
> at
> org.apache.flink.api.java.io.jdbc.JDBCUpsertOutputFormat.lambda$open$0(JDBCUpsertOutputFormat.java:124)
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
> at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
> at java.lang.Thread.run(Thread.java:748)
> 2020-03-20 21:16:21.247 [jdbc-upsert-output-format-thread-1] ERROR
> org.apache.flink.api.java.io.jdbc.JDBCUpsertOutputFormat - JDBC executeBatch
> error, retry times = 1
> org.postgresql.util.PSQLException: This connection has been closed.
> at
> org.postgresql.jdbc.PgConnection.checkClosed(PgConnection.java:857)
> at
> org.postgresql.jdbc.PgConnection.getAutoCommit(PgConnection.java:817)
> at
> org.postgresql.jdbc.PgStatement.internalExecuteBatch(PgStatement.java:813)
> at org.postgresql.jdbc.PgStatement.executeBatch(PgStatement.java:873)
> at
> org.postgresql.jdbc.PgPreparedStatement.executeBatch(PgPreparedStatement.java:1569)
> at
> org.apache.flink.api.java.io.jdbc.writer.AppendOnlyWriter.executeBatch(AppendOnlyWriter.java:62)
> at
> org.apache.flink.api.java.io.jdbc.JDBCUpsertOutputFormat.flush(JDBCUpsertOutputFormat.java:159)
> at
> org.apache.flink.api.java.io.jdbc.JDBCUpsertOutputFormat.lambda$open$0(JDBCUpsertOutputFormat.java:124)
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
> at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
> at java.lang.Thread.run(Thread.java:748)
> {code}
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