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6

The UPDATE query has an X lock on a key on "dbo.ACCOUNTS" blocking the SELECT from getting an S lock. The SELECT query has an S lock on a key of htt_customers_overlay_ultra. The UPDATE query has a U lock on the same key and is blocked trying to convert that to an X lock. The execution plan for the UPDATE doesn't feature Accounts at all so there is no ...


5

There are two stages to the lock of updated data. The first is an update lock (U) and the second, provided there is data that needs to be modified, is an exclusive lock (X). It's a two stage operation in the sense that there is data that needs to be searched in order to determine what/if data needs to be modified. The update lock will exist for that (or ...


5

If you look in the ERRORLOG file you'll probably see that the database is in the process of rolling commands forward or backward. Once that process is done the database will come back online. All you can do at this point is wait. DO NOT restart the SQL Server instance again. All you'll do is cause the SQL Server to start this process over again. However ...


4

Many experts share many ways on how to overcome this problem. These are my suggestions to play a safe game. Try to set the below command in a seperate session. SET SESSION TRANSACTION ISOLATION LEVEL READ UNCOMMITTED ; use db; SELECT COLA, COLB into outfile '/tmp/data.csv' from TABLE_NAME; COMMIT; exit; Doing by this way the SELECT statements are ...


2

If the values for the 'id' are adjacent, like '1' and '2' in your example, including the case where they are not adjacent but there are no rows in the index with values in between them, then I would suggest that you are bumping into the index gap lock... which is part of "row" locking. InnoDB performs row-level locking in such a way that when it searches ...


2

The write is done in-memory first and flushed to disk (asynchronously) later. Any readers accessing a document will get the in-memory copy straight away, not waiting for the flush to disk to happen (otherwise the database would be disk bound in terms of performance). The reference about locks applies to the in-memory portion, and guarantees the atomicity ...


1

Since OPTIMIZE TABLE, ANALYZE TABLE, and REPAIR TABLE are DDL, full table locks are required. However, if all data is InnoDB, the latest version of MySQL is a little more lenient with DDL locks. Note the current MySQL Documentation on OPTIMIZE TABLE in InnoDB: Prior to Mysql 5.6.17, OPTIMIZE TABLE does not use online DDL (ALGORITHM=INPLACE). ...


1

Confirming what you already know, for future reference: "The time to acquire the initial locks is not counted as execution time." — http://dev.mysql.com/doc/refman/5.6/en/slow-query-log.html It stands to reason, at least to me, that a "slow query" is best defined as a query that is poorly-optimized and takes longer than it should even when ...


1

You can explicitly specify using : SET LOCK_TIMEOUT timeout_period timeout_period Is the number of milliseconds that will pass before Microsoft SQL Server returns a locking error. A value of -1 (default) indicates no time-out period (that is, wait forever). When a wait for a lock exceeds the time-out value, an error is returned. A value of 0 ...


1

MyISAM only locks for INSERT, UPDATE, and DELETE (a.k.a. DML) These issue full table locks each time (See MyISAM Documentation on Locking granularity). SELECTs get blocked by those statement. The exception is an INSERT with concurrent_insert=2 defined. Performing an explicit lock is unnecessary, although you are free to do so. You may need to check you ...


1

The only immediate harm I can think of is dealing with contention from the UPDATE. Normal INSERT, UPDATE, and DELETE commands execute a full table lock. Doing ON DUPLICATE KEY UPDATE should work the same. In addition, what if the row's size changes to the point that the row needs to be bigger that the row's original allocation because of increasing the ...


1

Three unlock table commands are COMMIT ROLLBACK DISCONNECT


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There is no UNLOCK TABLE statement in DB2. Locks are released automatically upon commit or rollback.


1

The commenter was correct -- your kill query 77 was killing your own thread's query... as was indicated by the fact that the row from the processlist indicated that thread 77 (you) was the thread that was currently running the SHOW FULL PROCESSLIST command. The way you fix your problem is by finding the step you took before running mysqldump, and undoing ...


1

Looking at the Stored Procedure, I see something rather unnatural. DELIMITER $$ DROP PROCEDURE IF EXISTS `adam_matan`.`AddPixel` $$ CREATE PROCEDURE `adam_matan`.`AddPixel` ( GivenType VARCHAR(20), GivenPixelData BLOB ) TheStoredProcedure:BEGIN DECLARE KeepPixels,DeleteLimit,MaxID INT; SET KeepPixels = 5; SET DeleteLimit = 100; INSERT ...



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