From: Hans van Dalen
Date: March 19 2004 7:55am
Subject: Re: locking issues
List-Archive: http://lists.mysql.com/mysql/162082
Message-Id: <6.0.3.0.0.20040319085513.0308f030@mail.hansvandalen.nl>
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>Excuse me for late response.
>
>When I do it from the mysql prompt it works fine but trough the API (I use 
>DAC for MySQL from microolap, maybe the bug is in there software!!) it 
>doesn't work fine.
>
>I have try it on several versions: 4.1.1, 5.0.0 and 4.0.0.
>
>Thank you for your help. If you think it is not a database bug or a API 
>bug I contact microolap for more support.
>
>hans
>
>At 19:38 8-3-04, you wrote:
>>Hans van Dalen <mysql@stripped> wrote:
>> >
>> > A question about locking. In my code (delphi but that doesn't much 
>> matter)
>> > I fire ad-hoc queries (select). Before the query i fire a locking query
>> > (read) for that particular tables. Something like this:
>> >
>> > lock tables tab1 a read, tab2 b read
>> > (execute)
>> > select * from tab1 a, tab2 b where.........
>> > (execute)
>> >
>> > In this case I get an error: tab1 is not locked using LOCK TABLES.
>>
>>Works fine for me:
>>
>>mysql> lock tables tab1 a read, tab2 b read;
>>Query OK, 0 rows affected (0.00 sec)
>>
>>mysql> select * from tab1 a, tab2 b where a.id=b.id;
>>+------+------+
>>| id   | id   |
>>+------+------+
>>|    2 |    2 |
>>+------+------+
>>1 row in set (0.00 sec)
>>
>>What exactly versions do you use?
>>
>> > If I change the locking query to: lock tables tab1 read, tab2 b read
>> > The first times I didn't get any error. But after some times of 
>> running my
>> > app the error: a is not locked using LOCK TABLES occur!?!?
>> >
>> > Ok finally I use the statement: lock tables tab1 read, tab1 a read, 
>> tab2 b
>> > read
>> > en everything works fine.
>> >
>> > The strangest thing about this is that sometimes it doesn't go wrong
>> > (locking using the lock statement with only the table aliases), other 
>> times
>> > it goes.
>> >
>> > When I execute the locking and the select query from my SQL explorer
>> > (borland) nothing is going wrong (makes no sense whatever you lock).
>> >
>> > It makes no difference I use version 4.0/4.1/5.0 (on suse linux).
>> >
>> > Anybody who has seen this before?????
>> >
>> > Okay the workaround is simple: don't use table aliases or use the above
>> > showed locking statement, but it makes me angry something like this 
>> errors
>> > are raised on unexpected moments in my production environment,.
>> >
>>
>>
>>
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