Liquibase lock - reasons

Question

I get this when running a lot of liquibase-scripts against a Oracle-server  SomeComputer is me   Waiting for changelog lock     Waiting for changelog lock     Waiting for changelog lock     Waiting for changelog lock     Waiting for changelog lock     Waiting for changelog lock     Waiting for changelog lock     Liquibase Update Failed  Could not acquire change log lock   Currently locked by SomeComputer  192 168 15 X  since 2013-03-20 13 39 SEVERE 2013-03-20 16 59 liquibase  Could not acquire change log lock   Currently locked by SomeComputer  192 168 15 X  since 2013-03-20 13 39 liquibase exception LockException  Could not acquire change log lock   Currently locked by SomeComputer  192 168 15 X  since 2013-03-20 13 39         at liquibase lockservice LockService waitForLock LockService java 81          at liquibase Liquibase tag Liquibase java 507          at liquibase integration commandline Main doMigration Main java 643          at liquibase integration commandline Main main Main java 116    Could it be that the number of simultaneous sessions transactions are reached  Anyone has any ideas

User · Answer

I appreciate this wasn t the OP s issue  but I ran into this issue recently with a different cause  For reference  I was using the Liquibase Maven plugin  liquibase-maven-plugin 3 1 1  with SQL Server   Anyway  I d erroneously copied and pasted a SQL Server  use  statement into one of my scripts that switches databases  so liquibase was running and updating the DATABASECHANGELOGLOCK  acquiring the lock in the correct database  but then switching databases to apply the changes  Not only could I NOT see my changes or liquibase audit in the correct database  but of course  when I ran liquibase again  it couldn t acquire the lock  as the lock had been released in the  wrong  database  and so was still locked in the  correct  database  I d have expected liquibase to check the lock was still applied before releasing it  and maybe that is a bug in liquibase  I haven t checked yet   but it may well be addressed in later versions  That said  I suppose it could be considered a feature   Quite a bit of a schoolboy error  I know  but I raise it here in case anyone runs into the same problem

User · Answer

You can safely delete the table manually or using query  It will be recreated automatically   DROP TABLE DATABASECHANGELOGLOCK

User · Answer

Sometimes truncating or dropping the table DATABASECHANGELOGLOCK doesn t work  I use PostgreSQL database and came across this issue a lot of times  What I do for solving is to rollback the prepared statements running in background for that database  Try to rollback all the prepared statements and try the liquibase changes again   SQL   SELECT gid FROM pg prepared xacts WHERE database  database name     If above statement returns any record  then rollback that prepared statement with following SQL statement   ROLLBACK PREPARED  gid obtained from above SQL

User · Answer

It is not mentioned which environment is used for executing Liquibase  In case it is Spring Boot 2 it is possible to extend liquibase lockservice StandardLockService without the need to run direct SQL statements which is much cleaner  E g           This class is enforcing to release the lock from the database          public class ForceReleaseLockService extends StandardLockService         Override     public int getPriority             return super getPriority   1              Override     public void waitForLock   throws LockException           try               super forceReleaseLock              catch  DatabaseException e                throw new LockException  Could not enforce getting the lock    e                     super waitForLock              The code is enforcing the release of the lock  This can be useful in test set-ups where the release call might not get called in case of errors or when the debugging is aborted   The class must be placed in the liquibase ext package and will be picked up by the Spring Boot 2 auto configuration

User · Answer

Sometimes if the update application is abruptly stopped  then the lock remains stuck  Then running UPDATE DATABASECHANGELOGLOCK SET LOCKED 0  LOCKGRANTED null  LOCKEDBY null where ID 1   against the database helps  You may also need to replace LOCKED 0 with LOCKED FALSE  Or you can simply drop the DATABASECHANGELOGLOCK table  it will be recreated

User · Answer

Edit june 2020 Don t follow this advice  It s caused trouble to many people over the years  It worked for me a long time ago and I posted it in good faith  but it s clearly not the way to do it  The DATABASECHANGELOCK table needs to have stuff in it  so it s a bad idea to just delete everything from it without dropping the table  Leos Literak  for instance  followed these instructions and the server failed to start  Original answer It s possibly due to a killed liquibase process not releasing its lock on the DATABASECHANGELOGLOCK table  Then  DELETE FROM DATABASECHANGELOGLOCK   might help you  Edit   Adrian Ber s answer provides a better solution than this  Only do this if you have any problems doing his solution

User · Answer

The problem was the buggy implementation of SequenceExists in Liquibase  Since the changesets with these statements took a very long time and was accidently aborted  Then the next try executing the liquibase-scripts the lock was held      lt changeSet author  user  id  123  gt       lt preConditions onFail  CONTINUE  gt         lt not gt  lt sequenceExists sequenceName  SEQUENCE NAME SEQ    gt  lt  not gt       lt  preConditions gt       lt createSequence sequenceName  SEQUENCE NAME SEQ   gt     lt  changeSet gt    A work around is using plain SQL to check this instead      lt changeSet author  user  id  123  gt       lt preConditions onFail  CONTINUE  gt               lt sqlCheck expectedResult  0  gt                select count    from user sequences where sequence name    SEQUENCE NAME SEQ                lt  sqlCheck gt       lt  preConditions gt       lt createSequence sequenceName  SEQUENCE NAME SEQ   gt     lt  changeSet gt    Lockdata is stored in the table DATABASECHANGELOCK  To get rid of the lock you just change 1 to 0 or drop that table and recreate

User · Answer

In postgres 12 I needed to use this command  UPDATE DATABASECHANGELOGLOCK SET LOCKED false  LOCKGRANTED null  LOCKEDBY null where ID 1

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