# Cassandra

This page describes the Optimization Pack for the component type Cassandra.

## Metrics

<table><thead><tr><th width="248">Metric</th><th width="142.33333333333331"></th><th>Description</th></tr></thead><tbody><tr><td>read_rate</td><td>ops/s</td><td>Read queries per second</td></tr><tr><td>read_response_time_p99</td><td>milliseconds</td><td>99th percentile of read queries response time</td></tr><tr><td>read_response_time_avg</td><td>milliseconds</td><td>Average response time of read queries</td></tr><tr><td>write_rate</td><td>ops/s</td><td>Write queries per second</td></tr><tr><td>write_response_time_p99</td><td>milliseconds</td><td>99th percentile of write queries response time</td></tr><tr><td>read_response_time_max</td><td>milliseconds</td><td>Maximum response time of read queries</td></tr><tr><td>total_rate</td><td>ops/s </td><td>Total queries per second</td></tr><tr><td>write_response_time_avg</td><td>milliseconds</td><td>Average response time of write queries</td></tr><tr><td>write_response_time_max</td><td>milliseconds</td><td>Maximum response time of write queries</td></tr><tr><td>read_response_time_p90</td><td>milliseconds</td><td>90th percentile of read queries response time</td></tr><tr><td>write_response_time_p90</td><td>milliseconds</td><td>90th percentile of write queries response time</td></tr></tbody></table>

## Parameters

<table><thead><tr><th width="220">Parameter</th><th>Type</th><th width="76">Unit</th><th width="167">Default Value</th><th width="180">Domain</th><th width="89">Restart</th><th>Description</th></tr></thead><tbody><tr><td>cassandra_compactionStrategy</td><td>categorical</td><td></td><td><code>SizeTieredCompactionStrategy</code></td><td><code>LeveledCompactionStrategy</code>, <code>SizeTieredCompactionStrategy</code>, <code>TimeWindowCompactionStrategy</code></td><td>yes</td><td>Compaction strategy in use</td></tr><tr><td>cassandra_concurrentReads</td><td>integer</td><td></td><td><code>32</code></td><td><code>2</code> → <code>128</code></td><td>yes</td><td>Concurrent Reads</td></tr><tr><td>cassandra_concurrentWrites</td><td>integer</td><td></td><td><code>32</code></td><td><code>2</code> → <code>128</code></td><td>yes</td><td>Concurrent Writes</td></tr><tr><td>cassandra_fileCacheSizeInMb</td><td>integer</td><td>megabytes</td><td><code>512</code></td><td><code>128</code> → <code>4096</code></td><td>yes</td><td>Total memory to use for SSTable-reading buffers</td></tr><tr><td>cassandra_memtableCleanupThreshold</td><td>real</td><td></td><td><code>0.11</code></td><td><code>0.01</code> → <code>0.99</code></td><td>yes</td><td>Ratio used for automatic memtable flush</td></tr><tr><td>cassandra_concurrentCompactors</td><td>integer</td><td></td><td><code>2</code></td><td><code>1</code> → <code>32</code></td><td>yes</td><td>Sets the number of concurrent compaction processes allowed to run simultaneously on a node</td></tr><tr><td>cassandra_commitlog_compression</td><td>categorical</td><td></td><td><code>NoCompressor</code></td><td><code>NoCompressor</code>, <code>LZ4Compressor</code>, <code>SnappyCompressor</code>, <code>DeflateCompressor</code></td><td></td><td>Sets the compression of commit log</td></tr><tr><td>cassandra_commitlog_segment_size_in_mb</td><td>integer</td><td>megabytes</td><td><code>32</code></td><td><code>8</code> → <code>32</code></td><td></td><td>Sets the segment size of commit log</td></tr><tr><td>cassandra_compaction_throughput_mb_per_sec</td><td>integer</td><td>megabytes/s </td><td><code>16</code></td><td><code>0</code> → <code>999</code></td><td></td><td>Sets the number of throughput for compaction</td></tr><tr><td>cassandra_commitlog_sync_period_in_ms</td><td>integer</td><td>milliseconds</td><td><code>10000</code></td><td><code>1</code> → <code>25000</code></td><td></td><td>Sets the sync period of commit log</td></tr></tbody></table>