Observe Performance Cookbook: Type Data Columns


There are slow queries related to data with a column extracted from a JSON column.


Use the Column header to convert variant columns to specific types such as string or int64. In OPAL, examples of applicable functions are string, int64, and parse_timestamp.


A field extracted from a JSON column has the type of variant. Processing variant values can be significantly more expensive in query execution and transform execution. Observe recommends casting fields that are extracted from a JSON column to an explicit type (for instance, use make_col cluster_uid:string(FIELDS.cluster_uid) instead of make_col cluster_uid:FIELDS.cluster_uid).