Copies one table to another. This lightweight, in-memory function copies the DDL and all user-created projections from the source table. Projection statistics for the source table are also copied. Thus, the source and target tables initially have identical definitions and share the same storage.
Although they share storage space, Vertica regards the tables as discrete objects for license capacity purposes. For example, a single-terabyte table and its copy initially consume only one TB of space. However, your Vertica license regards them as separate objects that consume two TB of space.
After the copy operation is complete, the source and copy tables are independent of each other, so you can perform DML operations on one table without impacting the other. These operations can increase the overall storage required for both tables.
If you create multiple copies of the same table concurrently, one or more of the copy operations is liable to fail. Instead, copy tables sequentially.
COPY_TABLE ( '[[database.]schema.]source-table', '[[database.]schema.]target-table' )
Specifies a schema, by default
If you specify a database, it must be the current database.
|source‑table||The source table to copy. Vertica copies all data from this table to the target table.|
The target table of the source table. If the target table already exists, Vertica appends the source to the existing table.
If the table does not exist, Vertica creates a table from the source table's definition, by calling
- Source table: SELECT
- Target schema/table (new): CREATE
- Target table (existing): INSERT
Table Attribute Requirements
The following attributes of both tables must be identical:
- Column definitions, including NULL/NOT NULL constraints
- Partitioning expression
- Number of projections
- Projection sort order
- Primary and unique key constraints. However, the key constraints do not have to be identically enabled.
If the target table has primary or unique key constraints enabled and moving the partitions will insert duplicate key values into the target table, Vertica rolls back the operation. Enforcing constraints requires disk reads and can slow the copy process.
- Number and definitions of text indices.
The following restrictions apply to the source and target tables:
- If the source and target partitions are in different storage tiers, Vertica returns a warning but the operation proceeds. The partitions remain in their existing storage tier.
- If the source table contains a sequence, Vertica converts the sequence to an integer before copying it to the target table. If the target table contains auto-increment, identity, or named sequence columns, Vertica cancels the copy and displays an error message.
- The following tables cannot be used as sources or targets:
- Temporary tables
- Virtual tables
- System tables
- External tables
If you call COPY_TABLE and the target table does not exist, the function creates the table automatically. In the following example, COPY_TABLE creates the target table
public.newtable. Vertica also copies all the constraints associated with the source table
public.product_dimension except foreign key constraints:
=> SELECT COPY_TABLE ( 'public.product_dimension', 'public.newtable'); -[ RECORD 1 ]-------------------------------------------------- copy_table | Created table public.newtable. Copied table public.product_dimension to public.newtable