MySQL Bugs: #32867: Caching Prepared Statements causes erroneous execution of left join queries

Bug #32867	Caching Prepared Statements causes erroneous execution of left join queries
Submitted:	30 Nov 2007 9:10	Modified:	31 Mar 2014 15:09
Reporter:	Surya Prabha Vadlamani	Email Updates:
Status:	Can't repeat	Impact on me:	None
Category:	Connector / J	Severity:	S2 (Serious)
Version:	5.0	OS:	Any
Assigned to:	Alexander Soklakov	CPU Architecture:	Any
Tags:	left join queries, prepared statement caches

Description:
If the prepared statements are cached in the My connector/J JDBC driver, left join queries do not work properly. 

In the left join query, if there is no corresponding row in the right table, null values are returned for its columns. The bug is that, if the above scenarios happens once, from then onwards, the query always returns NULL values for the columns of the right table. This does not happen when we switch off caching of Prepared Statements in the driver. 

How to repeat:
Create two tables with one-one relation. Turn on caching of prepared statements in the driver. Execute a left join query on the tables. Have the data such that for some rows of the left table, there are no corresponding rows in the right table.

Hi Surya and thanks for your report. Please attach full test case showing the problem... Now, just by reading it, what else would you expect caching to do?

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

Hi Surya. I'm still waiting on test case / explanation, I thought it was serious for you...

I close this report as "Can't repeat" because there is no feedback for a long time and codebase is too old. Please, feel free to reopen it if the problem still exists in current driver.