User-Defined Parser

A parser takes a stream of bytes and passes a corresponding sequence of tuples to the Vertica load process. You can use user-defined parser functions to parse:

• Data in formats not understood by the Vertica built-in parser.
• Data that requires more specific control than the built-in parser supplies.

For example, you can load a CSV file using a specific CSV library. See the Vertica SDK for two CSV examples.

COPY supports a single user-defined parser that you can use with a user-defined source and zero or more instances of a user-defined filter. If you implement a UDParser class, you must also implement a corresponding ParserFactory.

Sometimes, you can improve the performance of your parser by adding a chunker. A chunker divides up the input and uses multiple threads to parse it. Chunkers are available only in the C++ API. For details, see Cooperative Parse and UDChunker Class. Under special circumstances you can further improve performance by using apportioned load, an approach where multiple Vertica nodes parse the input.