These are the modules which are created for every index and control the settings and behaviour of the indices. For example, how many shards an index can use or the number of replicas a primary shard can have for that index etc. There are two types of index settings −
- Static − These can be set only at index creation time or on a closed index.
- Dynamic − These can be changed on a live index.
Static Index Settings
The following table shows the list of static index settings −
| Setting | Possible value | Description |
|---|---|---|
| index.number_of_shards | Defaults to 5, Maximum 1024 | The number of primary shards that an index should have. |
| index.shard.check_on_startup | Defaults to false. Can be True | Whether or not shards should be checked for corruption before opening. |
| index.codec | LZ4 compression. | Type of compression used to store data. |
| index.routing_partition_size | 1 | The number of shards a custom routing value can go to. |
| index.load_fixed_bitset_filters_eagerly | false | Indicates whether cached filters are pre-loaded for nested queries |
Dynamic Index Settings
The following table shows the list of dynamic index settings −
| Setting | Possible value | Description |
|---|---|---|
| index.number_of_replicas | Defaults to 1 | The number of replicas each primary shard has. |
| index.auto_expand_replicas | A dash delimited lower and upper bound (0-5) | Auto-expand the number of replicas based on the number of data nodes in the cluster. |
| index.search.idle.after | 30seconds | How long a shard cannot receive a search or get request until it’s considered search idle. |
| index.refresh_interval | 1 second | How often to perform a refresh operation, which makes recent changes to the index visible to search. |