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https://issues.apache.org/jira/browse/GROOVY-7673?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15020425#comment-15020425
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acefael commented on GROOVY-7673:
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marking the class non thread-safe would limit its utility quite a lot, to me.
in a threaded environment one would have to resort to creating and discarding
Sql instances a lot,
which in turn casts doubt on the built in caching mechanisms.
I understand that, in a multithreaded environment, and when using Sql with a
data source, any implicit state ought to be avoided, including the updateCount
and prepared statements. There's a performance penalty through that, which
cannot be avoided.
When using the Sql with a j.s.Connection it can cache all it wants and be
therefore non thread-safe.
Perhaps that's the distinction? Thread safe with a DataSource, non thread-safe
with a Connection?
[keyColumnNames|https://github.com/apache/incubator-groovy/blob/22c749fea5c41fdb89d4739ec9a2249d97de58cc/subprojects/groovy-sql/src/main/java/groovy/sql/Sql.java#L268]
appears to me another candidate for concurrency issues.
> groovy.sql.Sql race condition?
> ------------------------------
>
> Key: GROOVY-7673
> URL: https://issues.apache.org/jira/browse/GROOVY-7673
> Project: Groovy
> Issue Type: Question
> Affects Versions: 2.4.5
> Reporter: acefael
>
> I am using groovy.sql.Sql with a commons dbcp2 BasicDataSource and am
> encountering a stacktrace as in \[2\] below. I do create many identical
> closures with different data, and I pass them all at once to
> ExecutorService.invokeAll. The closures are all using the same Sql instance.
> I believe this is a race condition because it happens only when the database
> is over a network, and not when the database is local.
> To work around I can set Sql.cacheNamedQueries = false. Problem is reliably
> gone in this case. So I guess the culprit is in \[1\], with my sql already
> being cached in namedParamSqlCache, but not yet in namedParamIndexPropCache?
> \[1\] the line in the source code
> https://github.com/apache/incubator-groovy/blob/GROOVY_2_4_X/subprojects/groovy-sql/src/main/java/groovy/sql/Sql.java#L4407
> \[2\] the stacktrace
> {noformat}
> > java.lang.NullPointerException
> > at java.util.ArrayList.<init>(ArrayList.java:168) ~[?:1.8.0]
> > at groovy.sql.Sql.buildSqlWithIndexedProps(Sql.java:4422)
> > ~[groovy-all-2.4.5.jar:2.4.5]
> > at groovy.sql.Sql.checkForNamedParams(Sql.java:4369)
> > ~[groovy-all-2.4.5.jar:2.4.5]
> > at groovy.sql.Sql.getPreparedStatement(Sql.java:4360)
> > ~[groovy-all-2.4.5.jar:2.4.5]
> > at groovy.sql.Sql.getPreparedStatement(Sql.java:4439)
> > ~[groovy-all-2.4.5.jar:2.4.5]
> > at groovy.sql.Sql.execute(Sql.java:2366) ~[groovy-all-2.4.5.jar:2.4.5]
> > at groovy.sql.Sql.execute(Sql.java:2438) ~[groovy-all-2.4.5.jar:2.4.5]
> > at groovy.sql.Sql$execute$1.call(Unknown Source) ~[?:?]
> > at es.acefael.BaseMigration.execute(BaseMigration.groovy:2017)
> > ~[es-acefael-dostuff-SNAPSHOT.jar:?]
> {noformat}
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