CouchDB Compactions Test

Compaction operation is the way to reduce disk space usage by removing unused and old data from database or view index files. This operation is very similar to the vacuum (SQLite ex.). During compaction, the target CouchDB creates new file with the .compact extension and transfers only actual data into. Because of this, CouchDB checks first for the available disk space - it should be twice greater than the compacted file’s data. When all actual data is successfully transferred to the compacted file, CouchDB replaces the target with the compacted file.

This test monitors the target CouchDB server and reports the number of compactions running on the server. In addition, this test also reveals the number of compactions running for a long time and also reports the running time of compaction greater than the configured running time. Using this test, administrators can be alerted to irregularities in compaction process if any, and rectify them at a faster pace.

Target of the test : Apache CouchDB Server

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for the target Apache CouchDB Server.

Configurable parameters for the test

Parameter	Description
Test period	How often should the test be executed.
Host	The IP address of the target server that is being monitored.
Port	The port number through which the Couchdb server communicates. The default port is 5984.
Username	In order to monitor an Apache CouchDB server, a special database user account with Admin privilege has to be created in every Apache CouchDB server instance that requires monitoring. In the Username text box, specify the Username for monitoring the target Apache CouchDB server instance.To create a new user, refer Pre-requisites for Monitoring Apache CouchDB topic.
Password	Specify the password of the specified Username.
Confirm Password	Confirm the password by retyping it here.
Running Duration Seconds	Specify the duration (in seconds) for which a compaction should have executed for it to be regarded as a long running compaction. The default value is 10.
Detailed Diagnosis	To make diagnosis more efficient and accurate, the eG Enterprise embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option. The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled: The eG manager license should allow the detailed diagnosis capability Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.

Measurements made by the test

Measurement	Description	Measurement Unit	Interpretation
Number of compactions	Indicates the number of compactions running on the server.	Number
Long running compactions	Indicates the number of compactions running on the target server for a long time.	Number	Ideally, the value of this measure should be 0. A non-zero value is indicative of compaction issues. Use the detailed diagnosis of this measure to figure out the process Id, duration and started time of compaction process.
Maximum compaction time	Indicates the running time of compaction greater than the configured running time.	Seconds	A low value is desired for this measure.