143 lines
3.4 KiB
Plaintext
143 lines
3.4 KiB
Plaintext
[[indices-flush]]
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=== Flush API
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++++
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<titleabbrev>Flush</titleabbrev>
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++++
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Flushes one or more data streams or indices.
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[source,console]
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--------------------------------------------------
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POST /my-index-000001/_flush
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--------------------------------------------------
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// TEST[setup:my_index]
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[[flush-api-request]]
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==== {api-request-title}
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`POST /<target>/_flush`
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`GET /<target>/_flush`
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`POST /_flush`
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`GET /_flush`
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[[flush-api-desc]]
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==== {api-description-title}
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Flushing a data stream or index is the process of making sure that any data that is currently
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only stored in the <<index-modules-translog,transaction log>> is also
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permanently stored in the Lucene index. When restarting, {es} replays any
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unflushed operations from the transaction log into the Lucene index to bring it
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back into the state that it was in before the restart. {es} automatically
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triggers flushes as needed, using heuristics that trade off the size of the
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unflushed transaction log against the cost of performing each flush.
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Once each operation has been flushed it is permanently stored in the Lucene
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index. This may mean that there is no need to maintain an additional copy of it
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in the transaction log, unless <<index-modules-translog-retention,it is retained
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for some other reason>>. The transaction log is made up of multiple files,
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called _generations_, and {es} will delete any generation files once they are no
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longer needed, freeing up disk space.
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It is also possible to trigger a flush on one or more indices using the flush
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API, although it is rare for users to need to call this API directly. If you
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call the flush API after indexing some documents then a successful response
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indicates that {es} has flushed all the documents that were indexed before the
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flush API was called.
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[[flush-api-path-params]]
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==== {api-path-parms-title}
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`<target>`::
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(Optional, string)
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Comma-separated list of data streams, indices, and index aliases to flush.
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Wildcard expressions (`*`) are supported.
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+
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To flush all data streams and indices in a cluster, omit this parameter or use
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`_all` or `*`.
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[[flush-api-query-params]]
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==== {api-query-parms-title}
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include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=allow-no-indices]
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+
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Defaults to `true`.
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include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=expand-wildcards]
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+
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Defaults to `open`.
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`force`::
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+
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--
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(Optional, boolean)
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If `true`,
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the request forces a flush
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even if there are no changes to commit to the index.
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Defaults to `true`.
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You can use this parameter
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to increment the generation number of the transaction log.
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This parameter is considered internal.
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--
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include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=index-ignore-unavailable]
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`wait_if_ongoing`::
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+
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--
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(Optional, boolean)
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If `true`,
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the flush operation blocks until execution
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when another flush operation is running.
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If `false`,
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{es} returns an error
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if you request a flush
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when another flush operation is running.
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Defaults to `true`.
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--
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[[flush-api-example]]
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==== {api-examples-title}
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[[flush-api-specific-ex]]
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===== Flush a specific data stream or index
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[source,console]
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----
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POST /my-index-000001/_flush
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----
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// TEST[s/^/PUT my-index-000001\n/]
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[[flush-multi-index]]
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===== Flush several data streams and indices
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[source,console]
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----
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POST /my-index-000001,my-index-000002/_flush
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----
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// TEST[s/^/PUT my-index-000001\nPUT my-index-000002\n/]
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[[flush-api-all-ex]]
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===== Flush all data streams and indices in a cluster
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[source,console]
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----
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POST /_flush
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----
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