How to view cache statistics


Confluence provides statistics about its internal caches that allow you to track the size and hit ratio of each cache and tune it for better performance (if necessary). See Performance Tuning for more information.

設定可能なキャッシュ

システム管理者は Confluence の内部キャッシュのサイズを管理コンソールから変更することができ、Confluence を一度シャットダウンして、再起動する手順を踏まなくても、これらの変更は有効になります。定義済みのどのキャッシュ領域についても、含まれるユニットの最大数を個別に調整できます。

キャッシュ サイズが大きくなるほど、実行時に必要なメモリが多くなるため、Confluence の Java プロセスへのメモリの割り当てと、サーバー上で使用可能な物理メモリを見直す必要があります。

キャッシュ統計の表示とキャッシュサイズの変更

キャッシュ統計を表示するには、

  2. Click 'Cache Statistics' in the left-hand panel. There you will find a list of all objects cached within Confluence.
  3. Click the 'Advanced' tab for more detail. Below is an example for one of the most frequently used caches, the 'Content Object' cache.

名前

Percent Used

Effectiveness

Objects / Size

Hit / Miss / Expiry

サイズ調整

フラッシュ

Content Object

80%

73%

4023/5000

374550 / 140460 / 55044

サイズ調整

フラッシュ

生成される数値：

Percent Used:

=（オブジェクト）/（サイズ）

有効率:

=（ヒット）/（ヒット+ミス）

Objects / Size:

The number of entries in the cache / the number of total possible entries allowed (configurable).

Hit / Miss / Expiry:

必要なコンテンツがキャッシュで見つかった読み取りアクセス数 / 必要なコンテンツがキャッシュで見つからなかった読み取りアクセス数 / キャッシュから追い出されたオブジェクトの数。

サイズ調整

Use this option to specify a different maximum cache size. Enter a new cache size and click the 'Adjust Size' button to set it.

Flush:

キャッシュをフラッシュします。

For instance, to calculate Percent Used:

Percent Used = Objects / Size

Percent Used = 4023/5000 = 80%

To calculate Effectiveness:

Effectiveness = (Hits)/(Hits + Misses)

Effectiveness = 374550 / (374550 + 140460) = 73%

The clustered versions of Confluence use distributed cache called Tangosol Coherence.

Watching the Cache Contents

To see the specific items in the caches, view the cache statistics at <baseUrl>/admin/cachecontents.jsp.

Additional Notes about Configurable Caches

Changes to cache size configurations persist across confluence restarts as they are saved in the <confluence-home>/config/confluence-coherence-cache-config.xml file (or <confluence-home>/config/confluence-coherence-cache-config-clustered.xml for a clustered instance). In most cases, a Confluence administrator will never need to know about these files. However, if it is necessary to tune cache options other than the maximum cache size, this can be done by manually editing these files. See Cache Performance Tuning for details.

The cache configuration file is stored in a home directory of each cluster node. When a Confluence administrator changes a cache size, all running cluster nodes will automatically update their own configuration files in their respective home directories. However, if a cluster node is not running when an administrator adjusts a cache size, the /config/confluence-coherence-cache-config-clustered.xml file in its home directory will not be updated. Since cluster caches are configured by the first node to start, if a node with an outdated cache configuration is the first to start up, the whole cluster would end up using the configuration of that node. However, copying this file from one node to another would resolve this issue.

パフォーマンスのチューニング

If you need to tune your application when under high usage, you may like to review this document for suggestions.

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