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| title: How Statistics Work |
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| Each application or cache server that joins the cluster can collect and archive statistical data for analyzing system performance. |
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| <%=vars.product_name%> statistics can be enabled for a cluster, for an application, for a server, or for a region. Statistics gathered for a cluster, an application, or a cache server are saved to a file and can be archived, whereas region statistics are transient and accessible only through the API. |
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| <a id="how_statistics_work__section_C12B3CDFF04743688BA5F8FB374899D5"></a> |
| Set the configuration attributes that control cluster, application, or cache statistics collection in `gfsh` or in the `gemfire.properties` configuration file. You can also collect your own application defined statistics. |
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| When Java applications and servers join a cluster, they can be configured via the cluster configuration service to enable statistics sampling and whether to archive the statistics that are gathered. |
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| **Note:** |
| <%=vars.product_name%> statistics use the Java `System.nanoTimer` for nanosecond timing. This method provides nanosecond precision, but not necessarily nanosecond accuracy. For more information, see the online Java documentation for `System.nanoTimer` for the JRE you are using with <%=vars.product_name%>. |
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| Statistics sampling provides valuable information for ongoing system tuning and troubleshooting. Sampling statistics (not including time-based statistics) at the default sample rate does not impact overall cluster performance. We recommend enabling statistics sampling in production environments. We do not recommend enabling time-based statistics (configured with the enable-time-statistics property) in production environments. |
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