Index retention exception

[edmundoa]

Problem description

Using the current master, I'm getting these in my logs now:

2016-03-02 18:50:59,731 INFO : org.graylog2.indexer.retention.strategies.AbstractIndexCountBasedRetentionStrategy - Number of indices (24) higher than limit (Optional.of(20)). Running retention for 4 indices.
2016-03-02 18:50:59,731 ERROR: org.graylog2.periodical.IndexRetentionThread - Uncaught exception in periodical
java.lang.NumberFormatException
    at org.graylog2.indexer.Deflector.extractIndexNumber(Deflector.java:246) ~[classes/:?]
    at org.graylog2.indexer.IndexHelper.getOldestIndices(IndexHelper.java:49) ~[classes/:?]
    at org.graylog2.indexer.retention.strategies.AbstractIndexCountBasedRetentionStrategy.runRetention(AbstractIndexCountBasedRetentionStrategy.java:84) ~[classes/:?]
    at org.graylog2.indexer.retention.strategies.AbstractIndexCountBasedRetentionStrategy.retain(AbstractIndexCountBasedRetentionStrategy.java:77) ~[classes/:?]
    at org.graylog2.periodical.IndexRetentionThread.doRun(IndexRetentionThread.java:76) ~[classes/:?]
    at org.graylog2.plugin.periodical.Periodical.run(Periodical.java:77) [classes/:?]
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_74]
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) [?:1.8.0_74]
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) [?:1.8.0_74]
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) [?:1.8.0_74]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_74]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_74]
    at java.lang.Thread.run(Thread.java:745) [?:1.8.0_74]

Environment

• Graylog Version: 2.0.0-alpha.5