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Version: Java (Groovy)

Create a time table

This guide will show you how to create a time table. A time table is a ticking, in-memory table that adds new rows at a regular, user-defined interval. Its sole column is a timestamp column.

Time tables are often used as trigger tables, which, through the use of snapshotWhen, can:

  • reduce the update frequency of ticking tables.
  • create the history of a table, sampled at a regular interval.

timeTable​

The timeTable method creates a table that ticks at the input period. The period can be passed in as nanoseconds:

oneMinute = 60_000_000_000
result = timeTable(oneMinute)

Or as a duration string:

result = timeTable("PT2S")

In this example, the startTime argument was not provided, so the first row of the table will be approximately the current time. See this document for more details.

tip

Duration strings are formatted as "PTnHnMnS", where:

  • PT is the prefix to indicate a duration
  • n is a number
  • H, M, and S are the units of time (hours, minutes, and seconds, respectively)

timeTable with a start time​

You can also pass a startTime to specify the timestamp of the first row in the time table:

oneHourEarlier = minus(now(), parseDuration("PT1H"))

result = timeTable(oneHourEarlier, "PT2S").reverse()

When this code is run, result is initially populated with 1800 rows of data, one for every two seconds in the previous hour.

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By default, the result of timeTable is append-only. You can create a blink table with the TimeTable.Builder by calling the builder's blinkTable method. The resulting table only retains rows from the most recent update cycle:

result = timeTableBuilder().period("PT2S").blinkTable(true).build()