Index modules
editIndex modules
editIndex Modules are modules created per index and control all aspects related to an index.
Index Settings
editIndex level settings can be set per-index. Settings may be:
- static
- They can only be set at index creation time or on a closed index.
- dynamic
- They can be changed on a live index using the update-index-settings API.
Changing static or dynamic index settings on a closed index could result in incorrect settings that are impossible to rectify without deleting and recreating the index.
Static index settings
editBelow is a list of all static index settings that are not associated with any specific index module:
-
index.number_of_shards
-
The number of primary shards that an index should have. Defaults to 1.
This setting can only be set at index creation time. It cannot be
changed on a closed index. Note: the number of shards are limited to
1024
per index. This limitation is a safety limit to prevent accidental creation of indices that can destabilize a cluster due to resource allocation. The limit can be modified by specifyingexport ES_JAVA_OPTS="-Des.index.max_number_of_shards=128"
system property on every node that is part of the cluster. -
index.shard.check_on_startup
-
Whether or not shards should be checked for corruption before opening. When corruption is detected, it will prevent the shard from being opened. Accepts:
-
false
- (default) Don’t check for corruption when opening a shard.
-
checksum
- Check for physical corruption.
-
true
-
Check for both physical and logical corruption. This is much more expensive in terms of CPU and memory usage.
Expert only. Checking shards may take a lot of time on large indices.
-
-
index.codec
-
The
default
value compresses stored data with LZ4 compression, but this can be set tobest_compression
which uses DEFLATE for a higher compression ratio, at the expense of slower stored fields performance. If you are updating the compression type, the new one will be applied after segments are merged. Segment merging can be forced using force merge. -
index.routing_partition_size
-
The number of shards a custom routing value can go to.
Defaults to 1 and can only be set at index creation time. This value must be less
than the
index.number_of_shards
unless theindex.number_of_shards
value is also 1. See Routing to an index partition for more details about how this setting is used. -
index.load_fixed_bitset_filters_eagerly
-
Indicates whether cached filters are pre-loaded for
nested queries. Possible values are
true
(default) andfalse
. -
index.hidden
-
Indicates whether the index should be hidden by default. Hidden indices are not
returned by default when using a wildcard expression. This behavior is controlled
per request through the use of the
expand_wildcards
parameter. Possible values aretrue
andfalse
(default).
Dynamic index settings
editBelow is a list of all dynamic index settings that are not associated with any specific index module:
-
index.number_of_replicas
- The number of replicas each primary shard has. Defaults to 1.
-
index.auto_expand_replicas
-
Auto-expand the number of replicas based on the number of data nodes in the cluster.
Set to a dash delimited lower and upper bound (e.g.
0-5
) or useall
for the upper bound (e.g.0-all
). Defaults tofalse
(i.e. disabled). Note that the auto-expanded number of replicas only takes allocation filtering rules into account, but ignores any other allocation rules such as shard allocation awareness and total shards per node, and this can lead to the cluster health becomingYELLOW
if the applicable rules prevent all the replicas from being allocated. -
index.search.idle.after
-
How long a shard can not receive a search or get request until it’s considered
search idle. (default is
30s
)
-
index.refresh_interval
-
How often to perform a refresh operation, which makes recent changes to the
index visible to search. Defaults to
1s
. Can be set to-1
to disable refresh. If this setting is not explicitly set, shards that haven’t seen search traffic for at leastindex.search.idle.after
seconds will not receive background refreshes until they receive a search request. Searches that hit an idle shard where a refresh is pending will wait for the next background refresh (within1s
). This behavior aims to automatically optimize bulk indexing in the default case when no searches are performed. In order to opt out of this behavior an explicit value of1s
should set as the refresh interval.
-
index.max_result_window
-
The maximum value of
from + size
for searches to this index. Defaults to10000
. Search requests take heap memory and time proportional tofrom + size
and this limits that memory. See Scroll or Search After for a more efficient alternative to raising this. -
index.max_inner_result_window
-
The maximum value of
from + size
for inner hits definition and top hits aggregations to this index. Defaults to100
. Inner hits and top hits aggregation take heap memory and time proportional tofrom + size
and this limits that memory. -
index.max_rescore_window
-
The maximum value of
window_size
forrescore
requests in searches of this index. Defaults toindex.max_result_window
which defaults to10000
. Search requests take heap memory and time proportional tomax(window_size, from + size)
and this limits that memory. -
index.max_docvalue_fields_search
-
The maximum number of
docvalue_fields
that are allowed in a query. Defaults to100
. Doc-value fields are costly since they might incur a per-field per-document seek. -
index.max_script_fields
-
The maximum number of
script_fields
that are allowed in a query. Defaults to32
.
-
index.max_ngram_diff
-
The maximum allowed difference between min_gram and max_gram for NGramTokenizer and NGramTokenFilter.
Defaults to
1
.
-
index.max_shingle_diff
-
The maximum allowed difference between max_shingle_size and min_shingle_size
for the
shingle
token filter. Defaults to3
. -
index.blocks.read_only
-
Set to
true
to make the index and index metadata read only,false
to allow writes and metadata changes. -
index.blocks.read_only_allow_delete
-
Similar to
index.blocks.read_only
, but also allows deleting the index to make more resources available. The disk-based shard allocator may add and remove this block automatically.
Deleting documents from an index to release resources - rather than deleting the index itself - can increase the index size over time. When index.blocks.read_only_allow_delete
is set to true
, deleting documents is not permitted. However, deleting the index itself releases the read-only index block and makes resources available almost immediately.
Elasticsearch adds and removes the read-only index block automatically when the disk utilization falls below the high watermark, controlled by cluster.routing.allocation.disk.watermark.flood_stage.
-
index.blocks.read
-
Set to
true
to disable read operations against the index. -
index.blocks.write
-
Set to
true
to disable data write operations against the index. Unlikeread_only
, this setting does not affect metadata. For instance, you can close an index with awrite
block, but not an index with aread_only
block. -
index.blocks.metadata
-
Set to
true
to disable index metadata reads and writes. -
index.max_refresh_listeners
-
Maximum number of refresh listeners available on each shard of the index.
These listeners are used to implement
refresh=wait_for
. -
index.analyze.max_token_count
-
The maximum number of tokens that can be produced using _analyze API.
Defaults to
10000
. -
index.highlight.max_analyzed_offset
-
The maximum number of characters that will be analyzed for a highlight request.
This setting is only applicable when highlighting is requested on a text that was indexed without offsets or term vectors.
Defaults to
1000000
.
-
index.max_terms_count
-
The maximum number of terms that can be used in Terms Query.
Defaults to
65536
.
-
index.max_regex_length
-
The maximum length of regex that can be used in Regexp Query.
Defaults to
1000
. -
index.routing.allocation.enable
-
Controls shard allocation for this index. It can be set to:
-
all
(default) - Allows shard allocation for all shards. -
primaries
- Allows shard allocation only for primary shards. -
new_primaries
- Allows shard allocation only for newly-created primary shards. -
none
- No shard allocation is allowed.
-
-
index.routing.rebalance.enable
-
Enables shard rebalancing for this index. It can be set to:
-
all
(default) - Allows shard rebalancing for all shards. -
primaries
- Allows shard rebalancing only for primary shards. -
replicas
- Allows shard rebalancing only for replica shards. -
none
- No shard rebalancing is allowed.
-
-
index.gc_deletes
-
The length of time that a deleted document’s version number remains available for further versioned operations.
Defaults to
60s
. -
index.default_pipeline
-
The default ingest node pipeline for this index. Index requests will fail
if the default pipeline is set and the pipeline does not exist. The default may be
overridden using the
pipeline
parameter. The special pipeline name_none
indicates no ingest pipeline should be run. -
index.final_pipeline
-
The final ingest node pipeline for this index. Index requests
will fail if the final pipeline is set and the pipeline does not exist.
The final pipeline always runs after the request pipeline (if specified) and
the default pipeline (if it exists). The special pipeline name
_none
indicates no ingest pipeline will run.
Settings in other index modules
editOther index settings are available in index modules:
- Analysis
- Settings to define analyzers, tokenizers, token filters and character filters.
- Index shard allocation
- Control over where, when, and how shards are allocated to nodes.
- Mapping
- Enable or disable dynamic mapping for an index.
- Merging
- Control over how shards are merged by the background merge process.
- Similarities
- Configure custom similarity settings to customize how search results are scored.
- Slowlog
- Control over how slow queries and fetch requests are logged.
- Store
- Configure the type of filesystem used to access shard data.
- Translog
- Control over the transaction log and background flush operations.
- History retention
- Control over the retention of a history of operations in the index.
X-Pack index settings
edit- Index lifecycle management
- Specify the lifecycle policy and rollover alias for an index.