Wail Alkowaileet created ASTERIXDB-1220:
-------------------------------------------
Summary: Race condition in AObjectPrinter singleton instance
Key: ASTERIXDB-1220
URL: https://issues.apache.org/jira/browse/ASTERIXDB-1220
Project: Apache AsterixDB
Issue Type: Bug
Components: AsterixDB, Data Formats
Reporter: Wail Alkowaileet
Hi,
The bug appears clearly when two queries race to print their output using
AObjectPrinter singleton in the same DataFormat.
{noformat}
public void print(byte[] b, int start, int l, PrintStream ps)
throws AlgebricksException {
try {
listAccessor.set(b, start, l);
arg.first = ps;
listAccessor.accept(printVisitor, arg);
} catch (Exception ioe) {
throw new AlgebricksException(ioe);
}
}
{noformat}
Since there's only one instance of AObjectPrinter, this will be a critical
section and things will lose track (such as ps and listAccessor).
I think new printer should be instantiated for each query.
To produce the problem:
Running the query in two clients:
{noformat}
//As in runtimets/queries/open-closed/query-issue55.3.query.aql
for $x in [[1,3],[4,5,2],[-1,-3,0],["a"]]
return $x
{noformat}
interchange the execution sequence in the two threads such as:
Thread 1 run: listAccessor.set(b, start, l);
Thread 2 run: listAccessor.set(b, start, l);
Thread 1 resume running.
Thread 2 resume running.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
