Liquibase - Error on SYSTEM.DATABASECHANGELOGLOCK while re-executing a migration - liquibase

Question

I'm using Liquibase 3.0.2, Ant task updateDatabase and change sets defined directly inside SQL scripts using comments like
--liquibase formatted sql
--changeset com.noemalife:1 dbms:oracle
etc.
The first run works fine, all change sets are executed and DB objects (oracle) are deployed. I can see DATABASECHANGELOG and DATABASECHANGELOGLOCK tables filled up.
Then I try to re-run the Ant task with the same exact configuration, expecting Liquibase to say something like "Ok, all is already deployed, nothig to do here."
But I get this instead:
C:\Users\dmusiani\Desktop\liquibase-test>ant migrate
Buildfile: build.xml
migrate:
[copy] Copying 1 file to C:\Users\dmusiani\Desktop\liquibase-test
BUILD FAILED
liquibase.exception.LockException: liquibase.exception.DatabaseException: Error executing SQL CREATE
TABLE SYSTEM.DATABASECHANGELOGLOCK (ID INTEGER NOT NULL, LOCKED NUMBER(1) NOT NULL, LOCKGRANTED TIM
ESTAMP, LOCKEDBY VARCHAR2(255), CONSTRAINT PK_DATABASECHANGELOGLOCK PRIMARY KEY (ID)); on jdbc:oracl
e:thin:#localhost:1521:WBMDINSERT INTO SYSTEM.DATABASECHANGELOGLOCK (ID, LOCKED) VALUES (1, 0): ORA-
00955: nome giÓ utilizzato da un oggetto esistente
at liquibase.lockservice.LockServiceImpl.acquireLock(LockServiceImpl.java:122)
at liquibase.lockservice.LockServiceImpl.waitForLock(LockServiceImpl.java:62)
at liquibase.Liquibase.update(Liquibase.java:123)
at liquibase.integration.ant.DatabaseUpdateTask.executeWithLiquibaseClassloader(DatabaseUpda
teTask.java:45)
at liquibase.integration.ant.BaseLiquibaseTask.execute(BaseLiquibaseTask.java:70)
at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
at org.apache.tools.ant.Task.perform(Task.java:348)
at org.apache.tools.ant.Target.execute(Target.java:357)
at org.apache.tools.ant.Target.performTasks(Target.java:385)
at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
at org.apache.tools.ant.Project.executeTarget(Project.java:1306)
at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
at org.apache.tools.ant.Project.executeTargets(Project.java:1189)
at org.apache.tools.ant.Main.runBuild(Main.java:758)
at org.apache.tools.ant.Main.startAnt(Main.java:217)
at org.apache.tools.ant.launch.Launcher.run(Launcher.java:257)
at org.apache.tools.ant.launch.Launcher.main(Launcher.java:104)
Caused by: liquibase.exception.DatabaseException: Error executing SQL CREATE TABLE SYSTEM.DATABASECH
ANGELOGLOCK (ID INTEGER NOT NULL, LOCKED NUMBER(1) NOT NULL, LOCKGRANTED TIMESTAMP, LOCKEDBY VARCHAR
2(255), CONSTRAINT PK_DATABASECHANGELOGLOCK PRIMARY KEY (ID)); on jdbc:oracle:thin:#localhost:1521:W
BMDINSERT INTO SYSTEM.DATABASECHANGELOGLOCK (ID, LOCKED) VALUES (1, 0): ORA-00955: nome giÓ utilizza
to da un oggetto esistente
at liquibase.executor.jvm.JdbcExecutor.execute(JdbcExecutor.java:56)
at liquibase.executor.jvm.JdbcExecutor.execute(JdbcExecutor.java:98)
at liquibase.executor.jvm.JdbcExecutor.execute(JdbcExecutor.java:64)
at liquibase.database.AbstractJdbcDatabase.checkDatabaseChangeLogLockTable(AbstractJdbcDatab
ase.java:771)
at liquibase.lockservice.LockServiceImpl.acquireLock(LockServiceImpl.java:95)
... 21 more
Caused by: java.sql.SQLException: ORA-00955: nome giÓ utilizzato da un oggetto esistente
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:113)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:331)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:288)
at oracle.jdbc.driver.T4C8Oall.receive(T4C8Oall.java:754)
at oracle.jdbc.driver.T4CStatement.doOall8(T4CStatement.java:210)
at oracle.jdbc.driver.T4CStatement.executeForRows(T4CStatement.java:963)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1192)
at oracle.jdbc.driver.OracleStatement.executeInternal(OracleStatement.java:1731)
at oracle.jdbc.driver.OracleStatement.execute(OracleStatement.java:1701)
at liquibase.executor.jvm.JdbcExecutor$1ExecuteStatementCallback.doInStatement(JdbcExecutor.
java:86)
at liquibase.executor.jvm.JdbcExecutor.execute(JdbcExecutor.java:49)
... 25 more
Total time: 1 second
C:\Users\dmusiani\Desktop\liquibase-test>
It seems to me that Liquibase is trying to re-create the DATABASECHANGELOGLOCK table.
I have this problem when I run Liquibase with the Oracle "system" user (my patch cares about creating a couple of other users, thus for testing purposes I use system directly to do that).
The other strange thing is that after the system's patch run succesfully, in the lock table I can still see the lock is active.
When I run other patches in other schemas(ex. the ones created by the system's patch), I have the patch completing successfully and the lock released in the lock table; relaunching that patch behaves as expected: Liquibase detects the patch is already in place ad does nothing.
This said, now my doubt is if Liquibase has problems, in the system schema, in detecting the lock table is already existing (and fails trying to deploy it) or if there is some kind of locking/commit problem.
Any suggestion is welcome
Thanks
Davide

Answer 1

I'm facing the same issue as you.
From what I see from the sources, when running as SYSTEM, the following condition (DatabaseSnapshot#include) is evaluated to true.
if (database.isSystemObject(example)) {
return null;
}
Because of that, the creation will always be attempted.
I'm gonna work further on a patch and keep you updated.
And here is a patch proposal.