ALTER TABLE DEDUP ENABLE

Enable storage level data deduplication on inserts and configures UPSERT KEYS.

note

• Deduplication can only be enabled for Write-Ahead Log (WAL) tables.
• Enabling deduplication does not have any effect on the existing data and only applies to newly inserted data. This means that a table with deduplication enabled can still contain duplicate data.
• Enabling deduplication does not have any effect on modifying data with UPDATE statements.

Syntax

UPSERT KEYS list can include one or more columns with the following rules:

• The designated Timestamp column must be included in the UPSERT KEYS list.
• Columns of STRING and BINARY types cannot be used in the UPSERT KEYS list.

Running ALTER TABLE DEDUP ENABLE on a table that already has deduplication enabled is not an error.

In such cases, the UPSERT KEYS list overrides the previously set key column list.

Example

To enable deduplication on the TICKER_PRICE table for the ts and ticker columns, where ts is the designated timestamp for the table, use the following command:

ALTER TABLE TICKER_PRICE DEDUP ENABLE UPSERT KEYS(ts, ticker)

See more example at data deduplication page

See also

ALTER TABLE DEDUP DISABLE