??????RE: Row Cache hit issue
Thanks All. -- -- ??: "Steinmaurer, Thomas";; : 2017??9??20??(??) 1:38 ??: "user@cassandra.apache.org"; ????: RE: Row Cache hit issue 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.(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.(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.(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 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> wrote: And we are using C* 2.1.18. -- Original -- From: "";<2535...@qq.com>; Date: Wed, Sep 20, 2017 11:27 AM To: "user"; 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 The contents of this e-mail are intended for the named addressee only. It contains information that may be confidential. Unless you are the named addressee or an authorized designee, you may not copy or use it, or disclose it to anyone else. If you received it in error please notify us immediately and then destroy it. Dynatrace Austria GmbH (registration number FN 91482h) is a company registered in Linz whose registered office is at 4040 Linz, Austria, Freist?0?1dterstra?0?8e 313
RE: Row Cache hit issue
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.(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.(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.(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 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"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 The contents of this e-mail are intended for the named addressee only. It contains information that may be confidential. Unless you are the named addressee or an authorized designee, you may not copy or use it, or disclose it to anyone else. If you received it in error please notify us immediately and then destroy it. Dynatrace Austria GmbH (registration number FN 91482h) is a company registered in Linz whose registered office is at 4040 Linz, Austria, Freistädterstraße 313
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> wrote: > And we are using C* 2.1.18. > > > -- Original -- > *From: * "我自己的邮箱";<2535...@qq.com>; > *Date: * Wed, Sep 20, 2017 11:27 AM > *To: * "user"; > *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
Re: Row Cache hit issue
And we are using C* 2.1.18. -- Original -- From: "";<2535...@qq.com>; Date: Wed, Sep 20, 2017 11:27 AM To: "user"; 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
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