[infinispan-issues] [JBoss JIRA] (ISPN-686) JdbcStringBasedCacheStore loads previous data from store before an insert

[Sanne Grinovero (JIRA)]

    [ https://issues.jboss.org/browse/ISPN-686?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12714862#comment-12714862 ] 

Sanne Grinovero commented on ISPN-686:
--------------------------------------

I wonder if the race condition is really possible with a write-through configuration: in theory the writing node owns a lock on the written entry.

I guess it's more tricky for async cacheloader: it's unlikely because of the de-duplication of writes on the same key, but still possible.

Yes for Oracle you need a stored procedure to implement it properly, but what's wrong with suggesting & documenting that? Especially as many other databases do have a solution, like UPSERT or MERGE.

I don't like the Transactions approach as it could interfere with other transactions integration; this doesn't look like the proper layer to manage transactions.
                
> JdbcStringBasedCacheStore loads previous data from store before an insert
> -------------------------------------------------------------------------
>
>                 Key: ISPN-686
>                 URL: https://issues.jboss.org/browse/ISPN-686
>             Project: Infinispan
>          Issue Type: Bug
>          Components: Loaders and Stores
>    Affects Versions: 4.0.0.Final, 4.1.0.Final
>            Reporter: Sanne Grinovero
>            Assignee: Thomas Fromm
>             Fix For: 5.2.0.Alpha3, 5.2.0.Final
>
>
> The JdbcStringBasedCacheStore implementation loads the previous data on an insert to find out if it should generate an UPDATE or INSERT statement, while it would perform much better to just verify if the primary key exists.
> On top of this, some databases provide ways to avoid the need to check at all, like MySQL's " INSERT ... ON DUPLICATE KEY UPDATE"
> [http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html]

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