Hi,
additionally, with saved (key) caches, we had some sort of corruption (I think,
for whatever reason) once. So, if you see something like that upon Cassandra
startup:
INFO [main] 2017-01-04 15:38:58,772 AutoSavingCache.java (line 114) reading
saved cache /var/opt/xxx/cassandra/saved_caches/ks-cf-KeyCache-b.db
ERROR [main] 2017-01-04 15:38:58,891 CassandraDaemon.java (line 571) Exception
encountered during startup
java.lang.OutOfMemoryError: Java heap space
at java.util.ArrayList.<init>(ArrayList.java:152)
at
org.apache.cassandra.db.RowIndexEntry$Serializer.deserialize(RowIndexEntry.java:132)
at
org.apache.cassandra.service.CacheService$KeyCacheSerializer.deserialize(CacheService.java:365)
at
org.apache.cassandra.cache.AutoSavingCache.loadSaved(AutoSavingCache.java:119)
at
org.apache.cassandra.db.ColumnFamilyStore.<init>(ColumnFamilyStore.java:276)
at
org.apache.cassandra.db.ColumnFamilyStore.createColumnFamilyStore(ColumnFamilyStore.java:435)
at
org.apache.cassandra.db.ColumnFamilyStore.createColumnFamilyStore(ColumnFamilyStore.java:406)
at org.apache.cassandra.db.Keyspace.initCf(Keyspace.java:322)
at org.apache.cassandra.db.Keyspace.<init>(Keyspace.java:268)
at org.apache.cassandra.db.Keyspace.open(Keyspace.java:110)
at org.apache.cassandra.db.Keyspace.open(Keyspace.java:88)
at
org.apache.cassandra.service.CassandraDaemon.setup(CassandraDaemon.java:364)
at
org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:554)
at
org.apache.cassandra.service.CassandraDaemon.main(CassandraDaemon.java:643)
resulting in Cassandra going OOM, with a “reading saved cache” log entry close
before the OOM, you may have hit some sort of corruption. Workaround is to
physically delete the saved cache file and Cassandra will start up just fine.
Regards,
Thomas
From: Dikang Gu [mailto:dikan...@gmail.com]
Sent: Mittwoch, 20. September 2017 06:06
To: cassandra <user@cassandra.apache.org>
Subject: Re: Row Cache hit issue
Hi Peng,
C* periodically saves cache to disk, to solve cold start problem. If
row_cache_save_period=0, it means C* does not save cache to disk. But the cache
is still working, if it's enabled in table schema, just the cache will be empty
after restart.
--Dikang.
On Tue, Sep 19, 2017 at 8:27 PM, Peng Xiao
<2535...@qq.com<mailto:2535...@qq.com>> wrote:
And we are using C* 2.1.18.
------------------ Original ------------------
From: "我自己的邮箱";<2535...@qq.com<mailto:2535...@qq.com>>;
Date: Wed, Sep 20, 2017 11:27 AM
To: "user"<user@cassandra.apache.org<mailto:user@cassandra.apache.org>>;
Subject: Row Cache hit issue
Dear All,
The default row_cache_save_period=0,looks Row Cache does not work in this
situation?
but we can still see the row cache hit.
Row Cache : entries 202787, size 100 MB, capacity 100 MB, 3095293
hits, 6796801 requests, 0.455 recent hit rate, 0 save period in seconds
Could anyone please explain this?
Thanks,
Peng Xiao
--
Dikang
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