Designated timestamp

QuestDB offers the option to elect a column as a designated timestamp. This allows you to specify which column the tables will be indexed by in order to leverage time-oriented language features and high-performance functionalities.

A designated timestamp is elected by using the timestamp(columnName) function:

• during a CREATE TABLE operation
• during a SELECT operation (dynamic timestamp)
• when ingesting data via ILP, for tables that do not already exist in QuestDB, partitions are applied automatically by day by default with a timestamp column

info

• Checking if tables contain a designated timestamp column can be done via the tables() and table_columns() functions which are described in the meta functions documentation page.

• The native timestamp format used by QuestDB is a Unix timestamp in microsecond resolution. See Timestamps in QuestDB for more details.

Properties

• Only a column of type timestamp can be elected as a designated timestamp.
• Only one column can be elected for a given table.

Out-of-order policy

As of version 6.0.0, QuestDB supports the ingestion of records that are out-of-order (O3) by time. QuestDB detects and adjusts data ingestion for O3 data automatically and no manual configuration is required.

Advantages

Electing a designated timestamp allows you to:

• Partition tables by time range. For more information, see the partitions reference.
• Use time series joins such as ASOF JOIN. For more information, see the JOIN reference.