Hi...
I'm trying to get me head around a possible situation involving
locks/triggers.
Suppose I have two tables:
FooTBL
CatTBL
in FooTBL, I have a trigger that operates such that whenever a new row is
added to FooTBL, it's immeadiately copied to CatTBL.
I'm trying to understand what happens
David T. Ashley wrote:
Nigel wrote:
mod_php will persist the MySQL connection holding open any lock or
syncronisation token obtained through any of the three methods :
begin/commit, lock/unlock tables or get_lock/release_lock. PHP does
ensure that even in the event of timeouts or fatal
Nigel wrote:
mod_php will persist the MySQL connection holding open any lock or
syncronisation token obtained through any of the three methods :
begin/commit, lock/unlock tables or get_lock/release_lock. PHP does
ensure that even in the event of timeouts or fatal errors any shutdown
Hi,
I'm doing a PHP application, and there are just a few instances where I need
to do atomic operations on more than one table at a time and I can't express
what I want to do as a single SQL statement.
What I'm trying to guard against, naturally, is race conditions when more
than one process is
David T. Ashley wrote:
Hi,
I'm doing a PHP application, and there are just a few instances where I need
to do atomic operations on more than one table at a time and I can't express
what I want to do as a single SQL statement.
What I'm trying to guard against, naturally, is race conditions
Nigel wrote:
If you can't or won't do this properly by using a transactional table
and begin/commit at least look at using get_lock() based guard
conditions which only lock a string leaving the database accessable.
Whatever you do if you client is php install a shutdown handler to clean
up
David T. Ashley wrote:
Nigel wrote:
If you can't or won't do this properly by using a transactional table
and begin/commit at least look at using get_lock() based guard
conditions which only lock a string leaving the database accessable.
Whatever you do if you client is php install a
Hello.
Every thing depends on logic of your application. But I don't
see a big gain of using table-level locks on InnoDB. Among others
this might be helpful:
http://dev.mysql.com/doc/mysql/en/internal-locking.html
Scott Klarenbach [EMAIL PROTECTED] wrote:
I've got a good
I've got a good deal of experience using mysql, but never in a large
production environment with many concurrent users.
Using the InnoDB engine, what is the general practice for ensuring
data integrity when multiple users are writing to the same table?
Should I explicitly lock the table before I
Hello.
Use:
set autocommit=0;
or begin a transaction before executing 'select ... lock in share mode'.
Commit the tramsaction to release lock.
Mojtaba Faridzad [EMAIL PROTECTED] wrote:
Hi,
I am trying to learn more about InnoDB to convert MyISAM to InnoDB.
according to MySQL
Hi,
I am trying to learn more about InnoDB to convert MyISAM to InnoDB.
according to MySQL document, I can lock a record like this:
SELECT * FROM mytable WHERE id = '100' LOCK IN SHARE MODE;
I run this query and showed a message to stop the screen (waiting) and on
the other computer I run the
Howdy all,
quick question about how INNODB handles locks. If
autocommit is off and I perform a select statement
without then issuing a commit, will INNODB remove any
read locks that it issued? I would assume that the
locks would be removed when the statement finished.
Just want to verify that
Andre,
- Original Message -
From: Andre Charbonneau [EMAIL PROTECTED]
Newsgroups: mailing.database.myodbc
Sent: Monday, November 17, 2003 5:11 PM
Subject: row-level locking question...
Hi,
Let say that I have the following transaction:
1. Read value v1 from table t1.
2. Do some
Hi,
Let say that I have the following transaction:
1. Read value v1 from table t1.
2. Do some computation using v1.
3. Update value v2 from table t2.
If in the above I don't want any other concurrent transaction to read v2
until I'm done updating it, how should I put an exclusive lock on it?
On Mon, Nov 17, 2003 at 10:10:52AM -0500, Andre Charbonneau wrote:
Hi,
Let say that I have the following transaction:
1. Read value v1 from table t1.
2. Do some computation using v1.
3. Update value v2 from table t2.
If in the above I don't want any other concurrent transaction to read
Mike,
- Original Message -
From: Mike Gohlke [EMAIL PROTECTED]
Newsgroups: mailing.database.mysql
Sent: Saturday, December 07, 2002 6:44 PM
Subject: Re: Innodb row locking question
Benjamin Pflugmann wrote:
Hello.
On Fri 2002-12-06 at 10:28:23 -0600, [EMAIL PROTECTED] wrote
Hello.
On Fri 2002-12-06 at 10:28:23 -0600, [EMAIL PROTECTED] wrote:
Heikki and all,
I've got a quick question which may be more general sql related but
since I'm using innodb tables specifically for the row locking.
The following process description is specifically designed to prevent
Benjamin Pflugmann wrote:
Hello.
On Fri 2002-12-06 at 10:28:23 -0600, [EMAIL PROTECTED] wrote:
Heikki and all,
I've got a quick question which may be more general sql related but
since I'm using innodb tables specifically for the row locking.
The following process description is
Hello.
On Sat 2002-12-07 at 10:36:00 -0600, [EMAIL PROTECTED] wrote:
[...]
Why do you repeat job_id = 111 and thread_id = 0? If you are using a
transaction seperation level of at least REPEATABLE READ (which is the
default), InnoDb assures that you always see the same rows within one
Heikki and all,
I've got a quick question which may be more general sql related but
since I'm using innodb tables specifically for the row locking.
The following process description is specifically designed to prevent
duplicates.
My current process:
select * from run where job_id = 111 and
On Wed, Dec 26, 2001 at 04:23:46PM -0600, Philip Molter wrote:
Are there guides out there for configuring these things? What is
a big enough log file? Honestly, on a lot of stuff, I'm just
guessing, but it takes a lot of time to fiddle with values, clean
out the database, and then shove in
:[EMAIL PROTECTED]]
Sent: Wednesday, December 26, 2001 3:19 PM
To: [EMAIL PROTECTED]
Subject: Re: MyISAM/InnoDB/Oracle comparison, and a InnoDB table locking
question
Walt,
thank you for the test!
This post is partially a reply to a request to share my
MyISAM/InnoDB/Oracle
comparison testing
This post is partially a reply to a request to share my MyISAM/InnoDB/Oracle
comparison testing with you guys. In addition, I have a question about
locking mechanisms in InnoDB which I'll ask at the end of the post.
I've been comparison testing MyISAM, InnoDB, and Oracle for the past two
weeks
Walt,
thank you for the test!
This post is partially a reply to a request to share my MyISAM/InnoDB/Oracle
comparison testing with you guys. In addition, I have a question about
locking mechanisms in InnoDB which I'll ask at the end of the post.
I've been comparison testing MyISAM, InnoDB, and
On Thu, Dec 27, 2001 at 12:18:38AM +0200, Heikki Tuuri wrote:
: The MyISAM table obviously fit in the OS file cache, otherwise 1750 inserts
: per second would not be possible. Did the table fit in the buffer pool of
: InnoDB or the SGA of Oracle? Did you commit each insert individually in
:
Philip,
On Thu, Dec 27, 2001 at 12:18:38AM +0200, Heikki Tuuri wrote:
: The MyISAM table obviously fit in the OS file cache, otherwise 1750 inserts
: per second would not be possible. Did the table fit in the buffer pool of
: InnoDB or the SGA of Oracle? Did you commit each insert individually
On 19 Aug 2001 19:29:17 +0100, Wesley Darlington wrote:
Hi,
Howdy.
On Thu, Aug 16, 2001 at 02:04:25PM +0100, Ken Guest wrote:
At the moment, what I am doing is:
execute LOCK TABLES foo READ
select info from foo
//next lock implictly unlocks previous one
//as it's
Hi,
On Thu, Aug 16, 2001 at 02:04:25PM +0100, Ken Guest wrote:
At the moment, what I am doing is:
execute LOCK TABLES foo READ
select info from foo
//next lock implictly unlocks previous one
//as it's done by the same thread/process
//chances of conflicts
On Thu, Aug 16, 2001 at 02:04:25PM +0100, Ken Guest wrote:
hi,
I'm new to this list, but not so new to using MySQL and have a question
about locking. (This is my first foray into datalocking with MySQL.)
I'd like to lock a table (a row in that table would be better) for read
and write
hi,
I'm new to this list, but not so new to using MySQL and have a question
about locking. (This is my first foray into datalocking with MySQL.)
I'd like to lock a table (a row in that table would be better) for read
and write access to prevent mishaps from occurring during data
manipulation.
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