nodetool compact
Where is the cassandra-env.sh file?
The location of the cassandra-env.sh file depends on the type of installation:
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Package installations + Installer-Services installations |
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Tarball installations + Installer-No Services installations |
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Forces a major compaction on one or more tables.
Synopsis
nodetool [options] compact [(-et <end_token> | --end-token <end_token>)]
[(-s | --split-output)] [(-st <start_token> | --start-token <start_token>)] [--] [<keyspace> [<tables>...]]
[--user-defined] <relative_path_to_SSTable file>...Tarball and Installer No-Services path:
<installation_location>/resources/cassandra/binCommon options
These options apply to all nodetool commands.
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Hostname or IP address. |
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Remote JMX agent port number. |
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Password. |
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Password file path. |
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Remote JMX agent user name. |
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Separates an option from an argument that could be mistaken for an option. |
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Compact options
The following options are specific to the compact command:
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Specify a token at which the compaction range ends.
Requires start token ( |
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Specify a token at which the compaction range starts.
Requires end token ( |
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Split output when using STCS to files that are 50%-25%-12.5% and so on of the total size.
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keyspace [tables] |
Run compaction on an entire keyspace or specified tables; use a space to separate table names. |
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Run compaction on one or more SSTables. Specify the relative paths and file names. |
Description
This command starts the compaction process on tables using SizeTieredCompactionStrategy (STCS), TimeWindowCompactionStrategy (TWCS), or Leveled compaction (LCS):
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If you do not specify a keyspace or table, a major compaction is run on all keyspaces and tables.
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If you specify only a keyspace, a major compaction is run on all tables in that keyspace.
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If you specify one or more tables, a major compaction is run on those tables.
Major compactions may behave differently depending which compaction strategy is used for the affected tables:
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SizeTieredCompactionStrategy (STCS): The default compaction strategy. This strategy triggers a minor compaction when there are a number of similar sized SSTables on disk as configured by the table subproperty,min_threshold. A minor compaction does not involve all the tables in a keyspace. Also see STCS compaction subproperties. -
DateTieredCompactionStrategy (DTCS)(deprecated) -
TimeWindowCompactionStrategy (TWCS)This strategy is an alternative for time series data. TWCS compacts SSTables using a series of time windows. While with a time window, TWCS compacts all SSTables flushed from memory into larger SSTables using STCS. At the end of the time window, all of these SSTables are compacted into a single SSTable. Then the next time window starts and the process repeats. The duration of the time window is the only setting required. See TWCS compaction subproperties. For more information about TWCS, see How is data maintained?. -
LeveledCompactionStrategy (LCS): The leveled compaction strategy creates SSTables of a fixed, relatively small size (160 MB by default) that are grouped into levels. Within each level, SSTables are guaranteed to be non-overlapping. Each level (L0, L1, L2 and so on) is 10 times as large as the previous. Disk I/O is more uniform and predictable on higher than on lower levels as SSTables are continuously being compacted into progressively larger levels. At each level, row keys are merged into non-overlapping SSTables in the next level. This process can improve performance for reads, because the database can determine which SSTables in each level to check for the existence of row key data. This compaction strategy is modeled after Google’s LevelDB implementation. Also see LCS compaction subproperties.
For more details, see How is data maintained? and Configuring compaction.
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A major compaction incurs considerably more disk I/O than minor compactions. |
