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https://issues.apache.org/jira/browse/IGNITE-8550?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16764141#comment-16764141
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Stanislav Lukyanov commented on IGNITE-8550:
--------------------------------------------
[~smoldachev] I'm OK with this style of the change, but we need to allow 0, 1
and 2, and not allow other values, so the check would be
{code}
if (updCnt < 0 || updCnt > 2)
U.warn(log, "Unexpected return value for update opetation [table=" +
em.fullTableName() + ", entry=" + entry + ", updCnt=" + updCnt + "]");
{code}
And I would even like a little hack with checking the dialect here. It's smelly
but it's simple.
{code}
if (dialect instanceof MySQLDialect) {
if (updCnt < 0 || updCnt > 2)
U.warn(log, "Unexpected return value for update opetation [table=" +
em.fullTableName() + ", entry=" + entry + ", updCnt=" + updCnt + "]");
} else {
if (updCnt != 1)
U.warn(log, "Unexpected return value for update opetation [table=" +
em.fullTableName() + ", entry=" + entry + ", updCnt=" + updCnt + "]");
}
{code}
Also we need a proper comment with a link to this issue that explains why the
code is like his.
> CacheAbstractJdbcStore expects merge to always return 1 but MySQL may also
> return 2 or 0
> ----------------------------------------------------------------------------------------
>
> Key: IGNITE-8550
> URL: https://issues.apache.org/jira/browse/IGNITE-8550
> Project: Ignite
> Issue Type: Bug
> Components: cache
> Reporter: Stanislav Lukyanov
> Assignee: Moldachev Sergey
> Priority: Minor
> Labels: newbie
> Fix For: 2.8
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> CacheAbstractJdbcStore.write attempts to execute a merge update if it is
> available, and expects the merge to always return 1 (as the number of updated
> entries is always 1).
> However, MySQL's `INSERT ... ON DUPLICATE KEY UPDATE`
> (https://dev.mysql.com/doc/refman/8.0/en/insert-on-duplicate.html) may return
> 0 or 2, depending on what was updated:
> {quote}With ON DUPLICATE KEY UPDATE, the affected-rows value per row is 1 if
> the row is inserted as a new row, 2 if an existing row is updated, and 0 if
> an existing row is set to its current values.{quote}
> Because of that, CacheAbstractJdbcStore may report a false warning.
> Need to consider either removing the warning or special-case the MySQL
> dialect to allow to return values other than 1.
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