q Data Structures

This page lists q objects that are referenced from elsewhere in the documentation.

General

.qsp.op

key	type	description
id	symbol	A unique name for this operator.
config	dict (...symbol: any)	Contains any custom configuration for the current operator.

Operators internal fields

The operator object contains a few other fields that are currently reserved for internal use.

.qsp.message

.qsp.message is a list containing 2 elements: the message metadata and the message event.

field	type	description
0	.qsp.message.metadata	The message metadata is a dictionary of meta information that applies to all the events in this message.
1	.qsp.message.event or .qsp.message.event[]	The events in this message. Each atom, tuple or record in this field is considered an event. If there are multiple events, metadata applies to all events in the message.

.qsp.message.metadata

key	type	description
key	.qsp.message.metadata.key	An optional partition key for the events in this message. This is used to group related collections of data based on a common attribute. Events that do not share the same key are considered independent and will be processed independent of other keys.
window	.qsp.temporal	Indicates the start time or index of a window of data.
offset	.qsp.integer or .qsp.temporal	An event offset is a number or time that represents the current message offset to the stream reader. This value will be used to recover data if messages are lost down stream. In the case messages need to be replayed, the message offset will be used to indicate the last successfully processed message.
isPartial	boolean	True if the message contains a partial window.
isLatePassthrough	boolean	True if the data being passed through is late

.qsp.message.event

.qsp.message.event is the payload for a given message. This data is most typically a table but can be any data type. Note that some operators explicitly require the event data to be a table to perform their desired operation.

.qsp.message.metadata.key

.qsp.message.metadata.key can be any of the following types:

long
int
short
byte
char
symbol
date
month

.qsp.temporal

.qsp.temporal can be any of the following types:

time
timestamp
timespan

.qsp.integer

.qsp.integer can be any of the following types:

long
int
short

.qsp.schema

.qsp.schema is a kdb table containing the details of the column details of a schema specified in the argument to Get Schema. It has the following meta

key	type	description	default
name	symbol	Schema name	`
datatype	short		0h
tokenize	boolean		0b
primary	boolean		0b

Example:

.qsp.getSchema`iceTrade

name           datatype tokenize primary
----------------------------------------
instrumentID   -11      0        0      
eventTimestamp -12      0        0      
price          -9       0        0      
quantity       -9       0        0      
tCond1         -7       0        0      
tTime          -12      0        0      
exchTime       -7       0        0      
uid            -7       0        0      
idCode         -7       0        0      
eVenueID       -7       0        0      
tMode          -11      0        0      
mmtuID         -11      0        0      
sourceID       -7       0        0