164 lines
5.4 KiB
Plaintext
164 lines
5.4 KiB
Plaintext
[[indices-segments]]
|
|
=== Indices Segments
|
|
|
|
Provide low level segments information that a Lucene index (shard level)
|
|
is built with. Allows to be used to provide more information on the
|
|
state of a shard and an index, possibly optimization information, data
|
|
"wasted" on deletes, and so on.
|
|
|
|
Endpoints include segments for a specific index:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
GET /test/_segments
|
|
--------------------------------------------------
|
|
// CONSOLE
|
|
// TEST[s/^/PUT test\n{"settings":{"number_of_shards":1, "number_of_replicas": 0}}\nPOST test\/test\?refresh\n{"test": "test"}\n/]
|
|
// TESTSETUP
|
|
|
|
For several indices:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
GET /test1,test2/_segments
|
|
--------------------------------------------------
|
|
// CONSOLE
|
|
// TEST[s/^/PUT test1\nPUT test2\n/]
|
|
|
|
Or for all indices:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
GET /_segments
|
|
--------------------------------------------------
|
|
// CONSOLE
|
|
|
|
Response:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
{
|
|
"_shards": ...
|
|
"indices": {
|
|
"test": {
|
|
"shards": {
|
|
"0": [
|
|
{
|
|
"routing": {
|
|
"state": "STARTED",
|
|
"primary": true,
|
|
"node": "zDC_RorJQCao9xf9pg3Fvw"
|
|
},
|
|
"num_committed_segments": 0,
|
|
"num_search_segments": 1,
|
|
"segments": {
|
|
"_0": {
|
|
"generation": 0,
|
|
"num_docs": 1,
|
|
"deleted_docs": 0,
|
|
"size_in_bytes": 3800,
|
|
"memory_in_bytes": 1410,
|
|
"committed": false,
|
|
"search": true,
|
|
"version": "7.0.0",
|
|
"compound": true,
|
|
"attributes": {
|
|
}
|
|
}
|
|
}
|
|
}
|
|
]
|
|
}
|
|
}
|
|
}
|
|
}
|
|
--------------------------------------------------
|
|
// TESTRESPONSE[s/"_shards": \.\.\./"_shards": $body._shards,/]
|
|
// TESTRESPONSE[s/"node": "zDC_RorJQCao9xf9pg3Fvw"/"node": $body.$_path/]
|
|
// TESTRESPONSE[s/"attributes": \{[^}]*\}/"attributes": $body.$_path/]
|
|
// TESTRESPONSE[s/: (\-)?[0-9]+/: $body.$_path/]
|
|
// TESTRESPONSE[s/7\.0\.0/$body.$_path/]
|
|
|
|
_0:: The key of the JSON document is the name of the segment. This name
|
|
is used to generate file names: all files starting with this
|
|
segment name in the directory of the shard belong to this segment.
|
|
|
|
generation:: A generation number that is basically incremented when needing to
|
|
write a new segment. The segment name is derived from this
|
|
generation number.
|
|
|
|
num_docs:: The number of non-deleted documents that are stored in this segment.
|
|
|
|
deleted_docs:: The number of deleted documents that are stored in this segment.
|
|
It is perfectly fine if this number is greater than 0, space is
|
|
going to be reclaimed when this segment gets merged.
|
|
|
|
size_in_bytes:: The amount of disk space that this segment uses, in bytes.
|
|
|
|
memory_in_bytes:: Segments need to store some data into memory in order to be
|
|
searchable efficiently. This number returns the number of bytes
|
|
that are used for that purpose. A value of -1 indicates that
|
|
Elasticsearch was not able to compute this number.
|
|
|
|
committed:: Whether the segment has been sync'ed on disk. Segments that are
|
|
committed would survive a hard reboot. No need to worry in case
|
|
of false, the data from uncommitted segments is also stored in
|
|
the transaction log so that Elasticsearch is able to replay
|
|
changes on the next start.
|
|
|
|
search:: Whether the segment is searchable. A value of false would most
|
|
likely mean that the segment has been written to disk but no
|
|
refresh occurred since then to make it searchable.
|
|
|
|
version:: The version of Lucene that has been used to write this segment.
|
|
|
|
compound:: Whether the segment is stored in a compound file. When true, this
|
|
means that Lucene merged all files from the segment in a single
|
|
one in order to save file descriptors.
|
|
|
|
attributes:: Contains information about whether high compression was enabled
|
|
|
|
[float]
|
|
==== Verbose mode
|
|
|
|
To add additional information that can be used for debugging, use the `verbose` flag.
|
|
|
|
NOTE: The format of the additional detail information is labelled as experimental in Lucene and it may change in the future.
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
GET /test/_segments?verbose=true
|
|
--------------------------------------------------
|
|
// CONSOLE
|
|
|
|
Response:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
{
|
|
...
|
|
"_0": {
|
|
...
|
|
"ram_tree": [
|
|
{
|
|
"description": "postings [PerFieldPostings(format=1)]",
|
|
"size_in_bytes": 2696,
|
|
"children": [
|
|
{
|
|
"description": "format 'Lucene50_0' ...",
|
|
"size_in_bytes": 2608,
|
|
"children" :[ ... ]
|
|
},
|
|
...
|
|
]
|
|
},
|
|
...
|
|
]
|
|
|
|
}
|
|
...
|
|
}
|
|
--------------------------------------------------
|
|
// NOTCONSOLE
|
|
//Response is too verbose to be fully shown in documentation, so we just show the relevant bit and don't test the response.
|