CONVERT TO DELTA

Function

This command converts an existing Parquet table to a Delta table in-place. This command lists all the files in the directory, creates a Delta Lake transaction log to track these files, and automatically infers the data schema by reading the footer of all Parquet files. The conversion process collects statistics to improve the query performance of the resulting Delta table. If a table name is provided, the metastore will also be updated to reflect that the table is now a Delta table.

Precautions

To convert partitioned tables, set spark.sql.forcePartitionPredicatesOnPartitionedTable.enabled to false.

Syntax

CONVERT TO DELTA [database_name.]table_name [NO STATISTICS]

Parameter Description

**Table 1** Parameter descriptions of CONVERT TO DELTA
Parameter	Description
database_name	Name of the database, consisting of letters, numbers, and underscores (_)
table_name	Name of the table in the database, consisting of letters, numbers, and underscores (_)
NO STATISTICS	The collection of statistics is bypassed during the conversion process to achieve faster conversion.

Required Permissions

SQL permissions

**Table 2** Permissions required for executing CONVERT TO DELTA
Permission Description
CREATE_TABLE permission on the database where the table is
ALTER permission on a table
INSERT_INTO_TABLE permission on a table
DROP_TABLE permission on a table

Fine-grained permissions: dli:database:createTable, dli:table:alter, dli:table:insertIntoTable, and dli:table:dropTable

Metadata services provided by LakeFormation. Refer to the LakeFormation documentation for details on permission configuration.

Example

create table if not exists parquet_table0 (id int,name string,price double) using parquet location 'obs://bucket_name0/db0/parquet_table0';
convert to delta parquet_table0;