# 9. Query Delimiters

AMPS provides a pair of delimiters, `group_begin` and `group_end`, that indicate when a query batch begins and ends.

## group_begin message

### Description

The `group_begin` message marks the beginning of a set of records returned by a SOW query. For more information, see the State of the World and SOW Queries chapters in the AMPS User Guide

### Header Fields

Field | Description
--- | ---
`Command` | Type of message. Always `group_begin`, as encoded by the protocol.
`QueryId` | The QueryId of the query that produced this message.

Table 9.1: Header fields provided in group_begin

## group_end message

### Description

The `group_end` message marks the end of a set of records returned by a SOW query. For more information, see the State of the World and SOW Queries chapters in the AMPS User Guide

### Header Fields

Field | Description
--- | ---
`Command` | Type of message. Always `group_end`, as encoded by the protocol.
`QueryId` | The QueryId of the query that produced this message.

Table 9.2: Header fields provided in group_end