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https://issues.apache.org/jira/browse/CASSANDRA-7597?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14073058#comment-14073058
]
Lyuben Todorov commented on CASSANDRA-7597:
-------------------------------------------
Its better to fail-fast when a bad config is detected as it's hard to interpret
what the config was supposed to be and attempt to fix it. My argument for -1
here is that logging exceptions without erroring out preemptively will lead to
further problems (further exception and a stacktrace that might be misleading)
and eventually a crash.
I'll give an example just to be clear. A missing {{commitlog_sync}} option from
cassandra.yaml would generate this error when trying to start the server:
{noformat}
ERROR 09:58:33 Fatal configuration error
org.apache.cassandra.exceptions.ConfigurationException: Missing required
directive CommitLogSync
at
org.apache.cassandra.config.DatabaseDescriptor.applyConfig(DatabaseDescriptor.java:162)
~[main/:na]
at
org.apache.cassandra.config.DatabaseDescriptor.<clinit>(DatabaseDescriptor.java:128)
~[main/:na]
at
org.apache.cassandra.service.CassandraDaemon.setup(CassandraDaemon.java:109)
[main/:na]
at
org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:454)
[main/:na]
at
org.apache.cassandra.service.CassandraDaemon.main(CassandraDaemon.java:543)
[main/:na]
Missing required directive CommitLogSync
Fatal configuration error; unable to start. See log for stacktrace.
{noformat}
I think that error is much clearer than what would happen if we just log the
exception and allow cassandra to continue, the below is the final exception
that is displayed:
{noformat}
ERROR 09:59:45 Exception encountered during startup
java.lang.NullPointerException: null
at java.util.Arrays$ArrayList.<init>(Arrays.java:2842) ~[na:1.7.0_60]
at java.util.Arrays.asList(Arrays.java:2828) ~[na:1.7.0_60]
at
org.apache.cassandra.service.CassandraDaemon.setup(CassandraDaemon.java:192)
[main/:na]
at
org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:454)
[main/:na]
at
org.apache.cassandra.service.CassandraDaemon.main(CassandraDaemon.java:543)
[main/:na]
java.lang.NullPointerException
at java.util.Arrays$ArrayList.<init>(Arrays.java:2842)
at java.util.Arrays.asList(Arrays.java:2828)
at
org.apache.cassandra.service.CassandraDaemon.setup(CassandraDaemon.java:192)
at
org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:454)
at
org.apache.cassandra.service.CassandraDaemon.main(CassandraDaemon.java:543)
Exception encountered during startup: null
{noformat}
Finally removing the {{System.exit(1|-1)}} and throwing exceptions instead
generates a similar stacktrace to what we do now, except its not as clean:
{noformat}
ERROR 10:07:59 Fatal configuration error
org.apache.cassandra.exceptions.ConfigurationException: Missing required
directive CommitLogSync
at
org.apache.cassandra.config.DatabaseDescriptor.applyConfig(DatabaseDescriptor.java:164)
~[main/:na]
at
org.apache.cassandra.config.DatabaseDescriptor.<clinit>(DatabaseDescriptor.java:128)
~[main/:na]
at
org.apache.cassandra.service.CassandraDaemon.setup(CassandraDaemon.java:109)
[main/:na]
at
org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:454)
[main/:na]
at
org.apache.cassandra.service.CassandraDaemon.main(CassandraDaemon.java:543)
[main/:na]
ERROR 10:07:59 Exception encountered during startup
java.lang.ExceptionInInitializerError: null
at
org.apache.cassandra.service.CassandraDaemon.setup(CassandraDaemon.java:109)
[main/:na]
at
org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:454)
[main/:na]
at
org.apache.cassandra.service.CassandraDaemon.main(CassandraDaemon.java:543)
[main/:na]
Caused by: java.lang.RuntimeException:
org.apache.cassandra.exceptions.ConfigurationException: Missing required
directive CommitLogSync
at
org.apache.cassandra.config.DatabaseDescriptor.<clinit>(DatabaseDescriptor.java:136)
~[main/:na]
... 3 common frames omitted
Caused by: org.apache.cassandra.exceptions.ConfigurationException: Missing
required directive CommitLogSync
at
org.apache.cassandra.config.DatabaseDescriptor.applyConfig(DatabaseDescriptor.java:164)
~[main/:na]
at
org.apache.cassandra.config.DatabaseDescriptor.<clinit>(DatabaseDescriptor.java:128)
~[main/:na]
... 3 common frames omitted
java.lang.ExceptionInInitializerError
at
org.apache.cassandra.service.CassandraDaemon.setup(CassandraDaemon.java:109)
at
org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:454)
at
org.apache.cassandra.service.CassandraDaemon.main(CassandraDaemon.java:543)
Caused by: java.lang.RuntimeException:
org.apache.cassandra.exceptions.ConfigurationException: Missing required
directive CommitLogSync
at
org.apache.cassandra.config.DatabaseDescriptor.<clinit>(DatabaseDescriptor.java:136)
... 3 more
Caused by: org.apache.cassandra.exceptions.ConfigurationException: Missing
required directive CommitLogSync
at
org.apache.cassandra.config.DatabaseDescriptor.applyConfig(DatabaseDescriptor.java:164)
at
org.apache.cassandra.config.DatabaseDescriptor.<clinit>(DatabaseDescriptor.java:128)
... 3 more
Exception encountered during startup: null
{noformat}
> System.exit() calls should be removed from DatabaseDescriptor
> -------------------------------------------------------------
>
> Key: CASSANDRA-7597
> URL: https://issues.apache.org/jira/browse/CASSANDRA-7597
> Project: Cassandra
> Issue Type: Bug
> Environment: Cassandra 2.0.9 (earlier version should be affected as
> well)
> Reporter: Pavel Sakun
>
> We're using SSTableSimpleUnsortedWriter API to generate SSTable to be loaded
> into cassandra. In case of any issue with config DatabaseDescriptor calls
> System.exit() which is apparently not the thing you expect while using API.
> Test case is simple:
> System.setProperty( "cassandra.config", "" );
> new YamlConfigurationLoader().loadConfig();
> Thread.sleep( 5000 );
> System.out.println("We're still alive"); // this will never be called
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