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https://issues.apache.org/jira/browse/CASSANDRA-5552?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Alexey Plotnik updated CASSANDRA-5552:
--------------------------------------

    Description: 
My cache related settings is default:
{quote}
key_cache_size_in_mb: # no value here
key_cache_save_period: 14400
row_cache_size_in_mb: 0
row_cache_save_period: 0
row_cache_provider: SerializingCacheProvider
saved_caches_directory: /var/opt/cassandra/data/saved_caches
{quote}

Every time I restart Cassandra node with *service cassandra stop; service 
cassandra start* commands I see with Zabbix or JMX or *nodetool info* the key 
cache has been nulled. It happens every time I restart the node. This situation 
is stable on all the nodes of the cluster. I guessed since the key cache is 
flushed to disk every 4 hours I should never see the situation with cold caches.

The output of *nodetool info* after 30 minutes from node has been started:
bq.Key Cache        : size 2105664 (bytes), capacity 104857584 (bytes), 3812 
hits, 47610 requests, 0.371 recent hit rate, 14400 save period in seconds

Before restarting it looked as follows:
bq.Key Cache        : size 104857584 (bytes), capacity 104857584 (bytes), 
79777150 hits, 502884072 requests, 0.847 recent hit rate, 14400 save period in 
seconds

All the nodes have the cache capacity auto-calculated to 104857584 (100 Mb) 
according to settings I put above.

The capacity of saved_caches directory on all the nodes is strange: with command

bq.ansible cassandra -i hosts -m raw -a 'du -s 
/var/opt/cassandra/data/saved_caches' | grep caches
I see values from 50 to 100 Kb only, against the values of 100Mb the `nodetool 
info` outputs.

After node restart in 1 week the key cache is filled up to ~2,2 million of 
keys, but when I perform node restart (after running for few days) it is nulled 
again.

I've never changed the default configuration of cassandra caches. What's going 
wrong? Thanks.

  was:
My cache related settings is default:
{quote}
key_cache_size_in_mb: # no value here
key_cache_save_period: 14400
row_cache_size_in_mb: 0
row_cache_save_period: 0
row_cache_provider: SerializingCacheProvider
saved_caches_directory: /var/opt/cassandra/data/saved_caches
{quote}

Every time I restart Cassandra node with *service cassandra stop; service 
cassandra start* I see with Zabbix or JMX or *nodetool info* the key cache was 
nulled. It happens every time I restart the node. This situation is on all the 
nodes I have. I guessed since key cache is flushed to disk every 4 hours I 
should never see the situation with cold caches.

nodetool info output after 30 minutes from node has been started:
bq.Key Cache        : size 2105664 (bytes), capacity 104857584 (bytes), 3812 
hits, 47610 requests, 0.371 recent hit rate, 14400 save period in seconds

Before restarting it looked as follows:
bq.Key Cache        : size 104857584 (bytes), capacity 104857584 (bytes), 
79777150 hits, 502884072 requests, 0.847 recent hit rate, 14400 save period in 
seconds

All the nodes have cache capacity auto-calculated to 104857584 (100 Mb)

The capacity of saved_caches directory on all the nodes is strange: with

bq.ansible cassandra -i hosts -m raw -a 'du -s 
/var/opt/cassandra/data/saved_caches' | grep caches
I see values from 50-100 Kb only against values of 100Mb the `nodetool info` 
outputs.

After node has been restarted in 1 week key cache is filled up to ~2,2 million 
of keys, but when I perform node restart (after > 4 hours of running) it nulled 
again.

I've never changed the default configuration of cassandra caches.

    
> Cassandra doesn't preload key caches from disk on start
> -------------------------------------------------------
>
>                 Key: CASSANDRA-5552
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-5552
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 1.1.9
>         Environment: CentOS 6.2, Datastax Cassandra Commutnity Edition package
>            Reporter: Alexey Plotnik
>              Labels: performance
>
> My cache related settings is default:
> {quote}
> key_cache_size_in_mb: # no value here
> key_cache_save_period: 14400
> row_cache_size_in_mb: 0
> row_cache_save_period: 0
> row_cache_provider: SerializingCacheProvider
> saved_caches_directory: /var/opt/cassandra/data/saved_caches
> {quote}
> Every time I restart Cassandra node with *service cassandra stop; service 
> cassandra start* commands I see with Zabbix or JMX or *nodetool info* the key 
> cache has been nulled. It happens every time I restart the node. This 
> situation is stable on all the nodes of the cluster. I guessed since the key 
> cache is flushed to disk every 4 hours I should never see the situation with 
> cold caches.
> The output of *nodetool info* after 30 minutes from node has been started:
> bq.Key Cache        : size 2105664 (bytes), capacity 104857584 (bytes), 3812 
> hits, 47610 requests, 0.371 recent hit rate, 14400 save period in seconds
> Before restarting it looked as follows:
> bq.Key Cache        : size 104857584 (bytes), capacity 104857584 (bytes), 
> 79777150 hits, 502884072 requests, 0.847 recent hit rate, 14400 save period 
> in seconds
> All the nodes have the cache capacity auto-calculated to 104857584 (100 Mb) 
> according to settings I put above.
> The capacity of saved_caches directory on all the nodes is strange: with 
> command
> bq.ansible cassandra -i hosts -m raw -a 'du -s 
> /var/opt/cassandra/data/saved_caches' | grep caches
> I see values from 50 to 100 Kb only, against the values of 100Mb the 
> `nodetool info` outputs.
> After node restart in 1 week the key cache is filled up to ~2,2 million of 
> keys, but when I perform node restart (after running for few days) it is 
> nulled again.
> I've never changed the default configuration of cassandra caches. What's 
> going wrong? Thanks.

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