Version: 0.4.0

Index configuration

This page describes how to configure an index.

In addition to the index_id, the index configuration lets you define five items:

The index-uri: it defines where the index files should be stored.
The doc mapping: it defines how a document and the fields it contains are stored and indexed for a given index.
The indexing settings: it defines the timestamp field used for sharding, and some more advanced parameters like the merge policy.
The search settings: it defines the default search fields default_search_fields, a list of fields that Quickwit will search into if the user query does not explicitly target a field.

Configuration is set at index creation and cannot be modified with the current version of Quickwit.

Config file format

The index configuration format is YAML. When a key is absent from the configuration file, the default value is used. Here is a complete example suited for the HDFS logs dataset:

version: 0.4 # File format version.

index_id: "hdfs"

index_uri: "s3://my-bucket/hdfs"

doc_mapping:
  mode: lenient
  field_mappings:
    - name: timestamp
      type: datetime
      input_formats:
        - unix_timestamp
      output_format: unix_timestamp_secs
      precision: seconds
      fast: true
    - name: severity_text
      type: text
      tokenizer: raw
    - name: body
      type: text
      tokenizer: default
      record: position
    - name: resource
      type: object
      field_mappings:
        - name: service
          type: text
          tokenizer: raw
  tag_fields: ["resource.service"]
  timestamp_field: timestamp

search_settings:
  default_search_fields: [severity_text, body]

retention:
  period: 90 days
  schedule: daily

Index ID

The index ID is a string that uniquely identifies the index within the metastore. It may only contain uppercase or lowercase ASCII letters, digits, hyphens (-), and underscores (_). Finally, it must start with a letter and contain at least 3 characters but no more than 255.

Index uri

The index-uri defines where the index files (also called splits) should be stored. This parameter expects a storage uri.

The index-uri parameter is optional. By default, the index-uri will be computed by concatenating the index-id with the default_index_root_uri defined in the Quickwit's config.

caution

The file storage will not work when running quickwit in distributed mode. Today, only the s3 storage is available when running several searcher nodes.

Doc mapping

The doc mapping defines how a document and the fields it contains are stored and indexed for a given index. A document is a collection of named fields, each having its own data type (text, binary, datetime, bool, i64, u64, f64).

Variable	Description	Default value
`field_mappings`	Collection of field mapping, each having its own data type (text, binary, datetime, bool, i64, u64, f64).	[]
`mode`	Defines how quickwit should handle document fields that are not present in the `field_mappings`. In particular, the "dynamic" mode makes it possible to use quickwit in a schemaless manner. (See mode)	`lenient`
`dynamic_mapping`	This parameter is only allowed when `mode` is set to `dynamic`. It then defines whether dynamically mapped fields should be indexed, stored, etc.	(See mode)
`tag_fields`	Collection of fields already defined in `field_mappings` whose values will be stored as part of the `tags` metadata. Learn more about tags.	[]
`store_source`	Whether or not the original JSON document is stored or not in the index.	false
`timestamp_field`	Timestamp field used for sharding documents in splits. The field has to be of type `datetime`. Learn more about time sharding.	None
`partition_key`	If set, quickwit will route documents into different splits depending on the field name declared as the `partition_key`.	null
`max_num_partitions`	Limits the number of splits created through partitioning. (See Partitioning)	200

Field types

Each field has a type that indicates the kind of data it contains, such as integer on 64 bits or text. Quickwit supports the following raw types text, i64, u64, f64, datetime, bool, and bytes, and also supports composite types such as array and object. Behind the scenes, Quickwit is using tantivy field types, don't hesitate to look at tantivy documentation if you want to go into the details.

Raw types

Text type

This field is a text field that will be analyzed and split into tokens before indexing. This kind of field is tailored for full-text search.

Example of a mapping for a text field:

name: body
description: Body of the document
type: text
tokenizer: default
record: position
fieldnorms: true

Parameters for text field

Variable	Description	Default value
`description`	Optional description for the field.	`None`
`stored`	Whether value is stored in the document store	`true`
`tokenizer`	Name of the `Tokenizer`, choices between `raw`, `default`, `en_stem` and `chinese_compatible`	`default`
`record`	Describes the amount of information indexed, choices between `basic`, `freq` and `position`	`basic`
`fieldnorms`	Whether to store fieldnorms for the field. Fieldnorms are required to calculate the BM25 Score of the document.	`false`
`fast`	Whether value is stored in a fast field. The fast field will contain the term ids. The effective cardinality depends on the tokenizer. When creating fast fields on text fields it is recommended to use the "raw" tokenizer, since it will store the original text unchanged. The "default" tokenizer will store the terms as lower case and this will be reflected in the dictionary (see tokenizers).	`false`

Description of available tokenizers

Tokenizer	Description
`raw`	Does not process nor tokenize text
`default`	Chops the text on according to whitespace and punctuation, removes tokens that are too long, and converts to lowercase
`en_stem`	Like `default`, but also applies stemming on the resulting tokens
`chinese_compatible`	Chop between each CJK character in addition to what `default` does. Should be used with `record: position` to be able to properly search

Description of record options

Record option	Description
`basic`	Records only the `DocId`s
`freq`	Records the document ids as well as the term frequency
`position`	Records the document id, the term frequency and the positions of occurrences.

Indexing with position is required to run phrase queries.

Numeric types: `i64`, `u64` and `f64` type

Quickwit handles three numeric types: i64, u64, and f64.

Numeric values can be stored in a fast field (the equivalent of Lucene's DocValues) which is a column-oriented storage.

Example of a mapping for an u64 field:

name: rating
description: Score between 0 and 5
type: u64
stored: true
indexed: true
fast: true

Parameters for i64, u64 and f64 field

Variable	Description	Default value
`description`	Optional description for the field.	`None`
`stored`	Whether the field values are stored in the document store	`true`
`indexed`	Whether the field values are indexed	`true`
`fast`	Whether the field values are stored in a fast field	`false`

`datetime` type

The datetime type handles dates and datetimes. Each datetime field can be configured to support multiple input formats. When specifying multiple input formats, the corresponding parsers are attempted in the order they are declared. The following formats are natively supported:

iso8601, rfc2822, rfc3339: parse dates using standard ISO and RFC formats.
strptime: parse dates using the Unix strptime format with few changes:
- strptime format specifiers: %C, %d, %D, %e, %F, %g, %G, %h, %H, %I, %j, %k, %l, %m, %M, %n, %R, %S, %t, %T, %u, %U, %V, %w, %W, %y, %Y, %%.
- %f for milliseconds precision support.
- %z timezone offsets can be specified as (+|-)hhmm or (+|-)hh:mm.
unix_timestamp: parse Unix timestamp values. Timestamp values can be provided in different precision, namely: seconds, milliseconds, microseconds, or nanoseconds. Quickwit is capable of inferring the precision from the value. Because of this feature, Quickwit only supports timestamp values ranging from 13 Apr 1972 23:59:55 to 16 Mar 2242 12:56:31.

When a datetime field is stored as a fast field, the precision parameter indicates the precision used to truncate the values before encoding which improves compression. The precision parameter can take the following values: seconds, milliseconds, microseconds. It only affects what is stored in fast fields when a datetime field is marked as fast field. Truncation here means zeroing. Operations on the datetime fastfield, e.g. via aggregations, need to be done on the microseconds level.

info

Internally datetime is stored as microseconds in the fastfield and docstore, and as seconds in the term dictionary.

danger

The timezone name format specifier (%Z) is not currently supported in strptime format.

In addition, Quickwit support the output_format field option to specify how datetimes are represented in search result. This options supports the same value as input formats except for Timestamp which is replace by the following formats are for finer grained control:

unix_timestamp_secs: displays timestamps in seconds.
unix_timestamp_millis: displays timestamps in milliseconds.
unix_timestamp_micros: displays timestamps in microseconds.

Example of a mapping for a datetime field:

name: timestamp
type: datetime
description: Time at which the event was emitted
input_formats:
  - rfc3339
  - unix_timestamp
  - "%Y %m %d %H:%M:%S.%f %z"
output_format: unix_timestamp_secs
stored: true
indexed: true
fast: true
precision: milliseconds

Parameters for datetime field

Variable	Description	Default value
`input_formats`	Formats used to parse input dates	[`rfc3339`, `unix_timestamp`]
`output_format`	Format used to display dates in search results	`rfc3339`
`stored`	Whether the field values are stored in the document store	`true`
`indexed`	Whether the field values are indexed	`true`
`fast`	Whether the field values are stored in a fast field	`false`
`precision`	The precision (`seconds`, `milliseconds`, or `microseconds`) used to store the fast values.	`seconds`

`bool` type

The bool type accepts boolean values.

Example of a mapping for a boolean field:

name: is_active
description: Activation status
type: bool
stored: true
indexed: true
fast: true

Parameters for bool field

Variable	Description	Default value
`description`	Optional description for the field.	`None`
`stored`	Whether value is stored in the document store	`true`
`indexed`	Whether value is indexed	`true`
`fast`	Whether value is stored in a fast field	`false`

`ip` type

The ip type accepts IP address values, both IpV4 and IpV6 are supported. Internally IpV4 are converted to IpV6.

Example of a mapping for an IP field:

name: host_ip
description: Host IP address
type: ip
fast: true

Parameters for IP field

Variable	Description	Default value
`description`	Optional description for the field.	`None`
`stored`	Whether value is stored in the document store	`true`
`indexed`	Whether value is indexed	`true`
`fast`	Whether value is stored in a fast field	`false`

`bytes` type

The bytes type accepts a binary value as a Base64 encoded string.

Example of a mapping for a bytes field:

name: binary
type: bytes
stored: true
indexed: true
fast: true

Parameters for bytes field

Variable	Description	Default value
`description`	Optional description for the field.	`None`
`stored`	Whether value is stored in the document store	`true`
`indexed`	Whether value is indexed	`true`
`fast`	Whether value is stored in a fast field. Only on 1:1 cardinality, not supported on `array<bytes>` fields	`false`

`json` type

The json type accepts a JSON object.

Example of a mapping for a JSON field:

name: parameters
type: json
stored: true
indexed: true
tokenizer: "default"
expand_dots: false

Parameters for JSON field

Variable	Description	Default value
`description`	Optional description for the field.	`None`
`stored`	Whether value is stored in the document store	`true`
`indexed`	Whether value is indexed	`true`
`tokenizer`	Only affects strings in the json object. Name of the `Tokenizer`, choices between `raw`, `default`, `en_stem` and `chinese_compatible`	`default`
`record`	Only affects strings in the json object. Describes the amount of information indexed, choices between `basic`, `freq` and `position`	`basic`
`expand_dots`	If true, json keys containing a `.` should be expanded. For instance, if `expand_dots` is set to true, `{"k8s.node.id": "node-2"}` will be indexed as if it was `{"k8s": {"node": {"id": "node2"}}}`. The benefit is that escaping the `.` will not be required at query time. In other words, `k8s.node.id:node2` will match the document. This does not impact the way the document is stored.	`true`

Note that the tokenizer and the record have the same definition and the same effect as for the text field.

To search into a json object, one then needs to extend the field name with the path that will lead to the target value.

For instance, when indexing the following object:

{
    "product_name": "droopy t-shirt",
    "attributes": {
        "color": ["red", "green", "white"],
        "size:": "L"
    }
}

Assuming attributes as been defined as a field mapping as follows:

- type: json
  name: attributes

attributes.color:red is then a valid query.

If, in addition, attributes is set as a default search field, then color:red is a valid query.

Composite types

array

Quickwit supports arrays for all raw types except for object types.

To declare an array type of i64 in the index config, you just have to set the type to array<i64>.

object

Quickwit supports nested objects as long as it does not contain arrays of objects.

name: resource
type: object
field_mappings:
  - name: service
    type: text

Mode

The mode describes how Quickwit should behave when it receives a field that is not defined in the field mapping.

Quickwit offers you three different modes:

lenient (default value): unmapped fields are dismissed by Quickwit.
strict: if a document contains a field that is not mapped, quickwit will dismiss it, and count it as an error.
dynamic: unmapped fields are gathered by Quickwit and handled as defined in the dynamic_mapping parameter.

dynamic_mapping offers the same configuration options as when configuring a json field. It defaults to:

- indexed: true
- stored: true
- tokenizer: default
- record: basic
- expand_dots: true

The dynamic mode makes it possible to operate Quickwit in a schemaless manner, or with a partial schema.

If the dynamic_mapping has been set as indexed (this is the default), fields that were mapped thanks to the dynamic mode can be searched, by targeting the path required to reach them from the root of the json object.

For instance, in a entirely schemaless settings, a minimal index configuration could be:

version: 0.4
index_id: my-dynamic-index
# note we did not map anything.
doc_mapping:
  mode: dynamic

We could then index a complex document like the following:

{
  "endpoint": "/admin",
  "query_params": {
    "ctk": "e42bb897d",
    "page": "eeb"
  },
  "src": {
    "ip": "8.8.8.8",
    "port": 53,
  },
  //...
}

The following queries are then valid, and match the document above.

// Fields can be searched simply.
endpoint:/admin

// Nested object can be queried by specifying a `.` separated
// path from the root of the json object to the given field.
query_params.ctk:e42bb897d

// numbers are searchable too
src.port:53

// and of course we can combine them with boolean operators.
src.port:53 AND query_params.ctk:e42bb897d

Field name validation rules

Currently Quickwit only accepts field name that matches the following regular expression: [a-zA-Z][_\.\-a-zA-Z0-9]*$

In plain language:

it needs to have at least one character.
it should only contain latin letter [a-zA-Z] digits [0-9] or (., -, _).
the first character needs to be a letter.

caution

For field names containing the . character, you will need to escape it when referencing them. Otherwise the . character will be interpreted as a JSON object property access. Because of this, it is recommended to avoid using field names containing the . character.

Behavior with fields not defined in the config

Fields in your JSON document that are not defined in the index config will be ignored.

Behavior with null values or missing fields

Fields with null or missing fields in your JSON document will be silently ignored when indexing.

Indexing settings

This section describes indexing settings for a given index.

Variable	Description	Default value
`commit_timeout_secs`	Maximum number of seconds before committing a split since its creation.	60
`split_num_docs_target`	Target number of docs per split.	10_000_000
`merge_policy`	Describes the strategy used to trigger split merge operations (see Merge policies section below).
`resources.heap_size`	Indexer heap size per source per index.	2_000_000_000

Merge policies

Quickwit makes it possible to define the strategy used to decide which splits should be merged together and when.

Quickwit offers three different merge policies, each with their own set of parameters.

"Stable log" merge policy

The stable log merge policy attempts to minimize write amplification AND keep time-pruning power as high as possible, by merging splits with a similar size, and with a close time span.

Quickwit's default merge policy is the stable_log merge policy with the following parameters:

version: 0.4
index_id: "hdfs"
# ...
indexing_settings:
  merge_policy:
    type: "stable_log"
    min_level_num_docs: 100_000
    merge_factor: 10
    max_merge_factor: 12

Variable	Description	Default value
`merge_factor`	(advanced) Number of splits to merge together in a single merge operation.	10
`max_merge_factor`	(advanced) Maximum number of splits that can be merged together in a single merge operation.	12
`min_level_num_docs`	(advanced) Number of docs below which all splits are considered as belonging to the same level.	100_000

"Limit Merge" merge policy

The limit merge policy is considered advanced.

The limit merge policy simply limits write amplification by setting an upperbound of the number of merge operation a split should undergo.

version: 0.4
index_id: "hdfs"
# ...
indexing_settings:
  merge_policy:
    type: "limit_merge"
    max_merge_ops: 5
    merge_factor: 10
    max_merge_factor: 12

Variable	Description	Default value
`max_merge_ops`	Maximum number of merges that a given split should undergo.	4
`merge_factor`	(advanced) Number of splits to merge together in a single merge operation.	10
`max_merge_factor`	(advanced) Maximum number of splits that can be merged together in a single merge operation.	12

No merge

The no_merge merge policy entirely disables merging.

caution

This setting is not recommended. Merges are necessary to reduce the number of splits, and hence improve search performances.

version: 0.4
index_id: "hdfs"
indexing_settings:
    merge_policy:
        type: "no_merge"

Indexer memory usage

Indexer works with a default heap of 2 GiB of memory. This does not directly reflect the overall memory usage, but doubling this value should give a fair approximation.

Search settings

This section describes search settings for a given index.

Variable	Description	Default value
`search_default_fields`	Default list of fields that will be used for search.	None

Retention policy

This section describes how Quickwit manages data retention. In Quickwit, the retention policy manager drops data on a split basis as opposed to individually dropping documents. Splits are evaluated based on their time_range which is derived from the index timestamp field specified in the (indexing_settings.timestamp_field) settings. Using this setting, the retention policy will delete a split when now() - split.time_range.end >= retention_policy.period

version: 0.4
index_id: hdfs
# ...
retention:
  period: 90 days
  schedule: daily

Variable	Description	Default value
`period`	Duration after which splits are dropped, expressed in a human-readable way (`1 day`, `2 hours`, `a week`, ...).	required
`schedule`	Frequency at which the retention policy is evaluated and applied, expressed as a cron expression (`0 0 * * * *`) or human-readable form (`hourly`, `daily`, `weekly`, `monthly`, `yearly`).	`hourly`

period is specified as set of time spans. Each time span is an integer followed by a unit suffix like: 2 days 3h 24min. The supported units are:

nsec, ns -- nanoseconds
usec, us -- microseconds
msec, ms -- milliseconds
seconds, second, sec, s
minutes, minute, min, m
hours, hour, hr, h
days, day, d
weeks, week, w
months, month, M -- a month is defined as 30.44 days
years, year, y -- a year is defined as 365.25 days

Config file format​

Index ID​

Index uri​

Doc mapping​

Field types​

Raw types​

Text type​

Description of available tokenizers​

Numeric types: i64, u64 and f64 type​

datetime type​

bool type​

ip type​

bytes type​

json type​

Composite types​

array​

object​

Mode​

Field name validation rules​

Behavior with fields not defined in the config​

Behavior with null values or missing fields​

Indexing settings​

Merge policies​

"Stable log" merge policy​

"Limit Merge" merge policy​

No merge​

Indexer memory usage​

Search settings​

Retention policy​

Config file format

Index ID

Index uri

Doc mapping

Field types

Raw types

Text type

Description of available tokenizers

Numeric types: `i64`, `u64` and `f64` type

`datetime` type

`bool` type

`ip` type

`bytes` type

`json` type

Composite types

array

object

Mode

Field name validation rules

Behavior with fields not defined in the config

Behavior with null values or missing fields

Indexing settings

Merge policies

"Stable log" merge policy

"Limit Merge" merge policy

No merge

Indexer memory usage

Search settings

Retention policy