User-defined parser

A parser takes a stream of bytes and passes a corresponding sequence of tuples to the Vertica load process.

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.

In this section