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: 0.6 # 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
      fast:
        - tokenizer: lowercase
    - 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. Instead, AWS S3, Azure Blob Storage, Google Cloud Storage (in s3 interoperability mode) or other S3-compatible storage systems including Scaleway Object Storage and Garage should be used as storage 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

*: tags fields and timestamp field are expressed as a path from the root of the JSON object to the given field. If a field name contains a . character, it needs to be escaped with a \ character.

Field types

Each field¹ 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, ip, 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
fast:
  normalizer: lowercase

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. (See tokenizers) for a list of available tokenizers.	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 and the dictionary. The default behaviour for true is to store the original text unchanged. The normalizers on the fast field is seperately configured. It can be configured via normalizer: lowercase. (See normalizers) for a list of available normalizers.	false

Description of available tokenizers

Tokenizer	Description
raw	Does not process nor tokenize text. Filters out tokens larger than 255 bytes.
default	Chops the text on according to whitespace and punctuation, removes tokens that are too long, and converts to lowercase. Filters out tokens larger than 255 bytes.
en_stem	Like default, but also applies stemming on the resulting tokens. Filters out tokens larger than 255 bytes.
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
lowercase	Applies a lowercase transformation on the text. It does not tokenize the text.

Description of available normalizers

Normalizer	Description
raw	Does not process nor tokenize text. Filters token larger than 255 bytes.
lowercase	Applies a lowercase transformation on the text. Filters token larger than 255 bytes.

Description of record options

Record option	Description
basic	Records only the DocIds
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 used for range queries and aggregations.

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. Since JSON doesn’t have a date type, the datetime field support multiple input types and formats. The supported input types are:

• floating-point or integer numbers representing a Unix timestamp
• strings containing a formatted date, datetime, or Unix timestamp

The input_formats field parameter specifies the accepted date formats. The following input formats are natively supported:

• iso8601
• rfc2822
• rfc3339
• strptime
• unix_timestamp

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 some variations:
  • 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.

danger

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

• unix_timestamp: parse float and integer numbers to Unix timestamps. Floating-point values are converted to timestamps expressed in seconds. Integer values are converted to Unix timestamps whose precision, determined in seconds, milliseconds, microseconds, or nanoseconds, is inferred from the number of input digits. Internally, datetimes are converted to UTC (if the time zone is specified) and stored as i64 integers. As a result, Quickwit only supports timestamp values ranging from Apr 13, 1972 23:59:55 to Mar 16, 2242 12:56:31.

danger

Converting timestamps from float to integer values may occurs with a loss of precision.

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 (truncation here means zeroing). The precision parameter can take the following values: seconds, milliseconds, microseconds, or nanoseconds. It only affects what is stored in fast fields when a datetime field is marked as "fast". Finally, operations on datetime fast fields, e.g. via aggregations, need to be done at the nanosecond level.

info

Internally datetime is stored in nanoseconds in fast fields and in the docstore, and in seconds in the term dictionary.

In addition, Quickwit supports the output_format field parameter to specify with which precision datetimes are deserialized. This parameter supports the same value as input formats except for unix_timestamp which is replaced by the following formats:

• unix_timestamp_secs: displays timestamps in seconds.
• unix_timestamp_millis: displays timestamps in milliseconds.
• unix_timestamp_micros: displays timestamps in microseconds.
• unix_timestamp_nanos: displays timestamps in nanoseconds.

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, microseconds, or nanoseconds) 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: raw
expand_dots: false
fast:
  normalizer: lowercase

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
fast	Whether value is stored in a fast field. The default behaviour for text in the JSON is to store the text unchanged. An normalizer can be configured via normalizer: lowercase. (See normalizers) for a list of available normalizers.	true
tokenizer	Only affects strings in the json object. Name of the Tokenizer, choices between raw, default, en_stem and chinese_compatible	raw
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:

• dynamic (default value): unmapped fields are gathered by Quickwit and handled as defined in the dynamic_mapping parameter.
• lenient: 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 Mapping

dynamic mode makes it possible to operate Quickwit in a schemaless manner, or with a partial schema. The configuration of dynamic mode can be set via the dynamic_mapping parameter. dynamic_mapping offers the same configuration options as when configuring a json field. It defaults to:

version: 0.6
index_id: my-dynamic-index
doc_mapping:
  mode: dynamic
  dynamic_mapping:
    indexed: true
    stored: true
    tokenizer: default
    record: basic
    expand_dots: true
    fast: true

When the dynamic_mapping is set as indexed (default), fields mapped through dynamic mode can be searched by targeting the path needed to access them from the root of the JSON object.

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

version: 0.6
index_id: my-dynamic-index
doc_mapping:
    # If you have a timestamp field, it is important to tell quickwit about it.
    timestamp_field: unix_timestamp
    # mode: dynamic #< Commented out, as dynamic is the default mode.

With such a simple configuration, we can 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 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.	10000000
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.	2000000000

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: 0.6
index_id: "hdfs"
# ...
indexing_settings:
  merge_policy:
    type: "stable_log"
    min_level_num_docs: 100000
    merge_factor: 10
    max_merge_factor: 12
    maturation_period: 48h

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.	100000
maturation_period	Duration after which a split is considered mature, and won't be considered for merges anymore. May impact the completion time of pending delete tasks.	48h

"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: 0.6
index_id: "hdfs"
# ...
indexing_settings:
  merge_policy:
    type: "limit_merge"
    max_merge_ops: 5
    merge_factor: 10
    max_merge_factor: 12
    maturation_period: 48h

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
maturation_period	Duration after which a split is considered mature, and won't be considered for merges anymore. May impact the completion time of pending delete tasks.	48h

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: 0.6
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
default_search_fields	Default list of fields that will be used for search. The field names in this list may be declared
explicitly in the schema, or may refer to a field captured by the dynamic mode.	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: 0.6
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