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What is a Search Attribute?

A Search Attribute is an indexed key used in a List Filter to filter a list of Workflow Executions that have the Search Attribute in their metadata.

note

If a Temporal Cluster does not have Elasticsearch integrated, but a Workflow Execution is spawned and tagged with Search Attributes, no errors occur. However, you won't be able to use Advanced Visibility List APIs and List Filters to find and list the Workflow Execution.

When using Continue-As-New or a Temporal Cron Job, Search Attributes are carried over to the new Run by default.

Default Search Attributes#

A Temporal Cluster that is integrated with Elasticsearch has a set of default Search Attributes already available. These Search Attributes are created when the initial index is created.

NAMETYPE
BatcherNamespaceKeyword
BatcherUserKeyword
BinaryChecksumsKeyword
CloseTimeDatetime
ExecutionDurationInt
ExecutionStatusKeyword
ExecutionTimeDatetime
HistoryLengthInt
RunIdKeyword
StartTimeDatetime
StateTransitionCountInt
TaskQueueKeyword
TemporalChangeVersionKeyword
WorkflowIdKeyword
WorkflowTypeKeyword
  • All default Search Attributes are reserved and read-only. (You cannot create a custom one with the same name or alter the existing one.)

  • ExecutionStatus values correspond to Workflow Execution Statuses: Running, Completed, Failed, Canceled, Terminated, ContinuedAsNew, TimedOut.

  • StartTime, CloseTime, and ExecutionTime are stored as dates but are supported by queries that use either EpochTime in nanoseconds or a string in RFC3339Nano format (such as "2006-01-02T15:04:05.999999999Z07:00").

  • ExecutionDuration is stored in nanoseconds but is supported by queries that use integers in nanoseconds, Golang duration format, or "hh:mm:ss" format.

  • CloseTime, HistoryLength, StateTransitionCount, and ExecutionDuration are present only in a Closed Workflow Execution.

  • ExecutionTime can differ from StartTime in retry and cron use cases.

Custom Search Attributes#

Custom Search Attribute keys must be added to a Temporal Cluster using tctl. Adding a Search Attribute key makes it available to use with Workflow Executions within that Cluster.

There is no hard limit on the number of attributes you can add. However, we recommend enforcing the following limits:

  • Number of keys: 100 per Workflow
  • Size of each value: 2 KB per value
  • Total size of keys and values: 40 KB per Workflow
note

Due to Elasticsearch limitations, you can only add Search Attributes. It is not possible to rename Search Attribute keys or remove them from the index schema.

Search Attributes must be one of the following types:

  • String
  • Keyword
  • Int
  • Double
  • Bool
  • Datetime

The temporalio/auto-setup Docker image uses a pre-defined set of custom Search Attributes that are handy for testing. Their names indicate their types:

  • CustomStringField
  • CustomKeywordField
  • CustomIntField
  • CustomDoubleField
  • CustomBoolField
  • CustomDatetimeField

Note:

  • Double is backed up by scaled_float Elasticsearch type with scale factor 10000 (4 decimal digits).
  • Datetime is backed up by date type with milliseconds precision in Elasticsearch 6 and date_nanos type with nanoseconds precision in Elasticsearch 7.
  • Int is 64-bit integer (long Elasticsearch type).
  • Keyword and String types are concepts taken from Elasticsearch. Each word in a String is considered a searchable keyword. For a UUID, that can be problematic because Elasticsearch indexes each portion of the UUID separately. To have the whole string considered as a searchable keyword, use the Keyword type. For example, if the key ProductId has the value of 2dd29ab7-2dd8-4668-83e0-89cae261cfb1:
    • As a Keyword it would be matched only by ProductId = "2dd29ab7-2dd8-4668-83e0-89cae261cfb1.
    • As a String it would be matched by ProductId = 2dd8, which could cause unwanted matches.
  • The String type cannot be used in the "Order By" clause.

Search Attributes as Workflow Execution metadata#

To actually have results from the use of a List Filter, Search Attributes must be added to a Workflow Execution as metadata. How to do this entirely depends on the method by which you spawn the Workflow Execution:

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