Skip to content
Kdb+ and q documentation
Reference architecture (coming soon)
Initializing search
Ask a question
Home
kdb+ and q
kdb Insights
kdb Insights Enterprise
Learn
Language
Database
Developing
Architecture
Help
Kdb+ and q documentation
Home
kdb+ and q
kdb+ and q
About
Reference card
Developer tools
Interfaces
Interfaces
KX libraries
Bloomberg
C/C++
C/C++
Quick guide
API reference
C API for kdb+ (WP)
Using C/C++ functions
Excel
FIX messaging (WP)
GPUs
Lightning tickerplants (WP)
Matlab
ODBC
ODBC3
ODBC/Simba
R
Scala
Open source
Machine learning
Using kdb+ in the cloud
Using kdb+ in the cloud
About
Amazon Web Services
Amazon Web Services
Reference architecture
Amazon EC2 & Storage Services
Amazon EC2 & Storage Services
Migrating a kdb+ HDB to Amazon EC2
Elastic Block Store (EBS)
EFS (NFS)
Amazon Storage Gateway
FSx for Lustre
AWS Lambda
Microsoft Azure
Microsoft Azure
Reference architecture (coming soon)
Google Cloud
Google Cloud
Reference architecture
Auto Scaling (WP)
Auto Scaling (WP)
About
Amazon Web Services
Realtime data cluster
Costs and risks
Surveillance in the Cloud (WP)
Other file systems
Other file systems
MapR-FS
Goofys
S3FS
S3QL
ObjectiveFS
WekaIO Matrix
Quobyte
DigitalOcean
Community
kdb+ and q forum
White papers
About this site
kdb Insights
kdb Insights Enterprise
Learn
Learn
Get started
Install
Licenses
Mountain tour
Mountain tour
TLDR
Begin here
The q session
Tables
CSVs
Datatypes
Scripts
IDE
Q for quants
Q by Examples
Q for All
Examples from Python
Examples from Python
Basic
Array
List
Strings
Dictionaries
Q for Mortals 3
Q by Puzzles
Q by Puzzles
About
12 Days of Xmas
ABC problem
Abundant odds
Four is magic
Name Game
Summarize and Say
Word wheel
Reading room
Reading room
Information desk
Boggle
Cats cradle
Fizz buzz
Klondike
Phrasebook
Scrabble
Application examples
Application examples
Astronomy (WP)
Bitcoin blockchains (WP)
Card counters (WP)
Corporate actions (WP)
Disaster management (WP)
Exoplanets (WP)
Market depth (WP)
Market fragmentation (WP)
Option pricing (WP)
Predicting floods (WP)
Signal processing (WP)
Space weather (WP)
Trading surveillance (WP)
Transaction-cost analysis (WP)
Trend indicators (WP)
Advanced q
Advanced q
Remarks on Style
Shifts & scans
Technical articles
Views
Origins
Terminology
Starting kdb+
Starting kdb+
Overview
The q language
IPC
Tables
Historical database
Realtime database
Language
Language
Reference card
By topic
Iteration
Iteration
Overview
Implicit iteration
Iterators
Maps
Accumulators
Guide to iterators (WP)
Keywords
Keywords
abs
aj, aj0, ajf, ajf0
all, any
and
asc, iasc, xasc
asof
attr
avg, avgs, mavg, wavg
bin, binr
ceiling
count, mcount
cols, xcol, xcols
cor
cos, acos
cov, scov
cross
csv
cut
delete
deltas
desc, idesc, xdesc
dev, mdev, sdev
differ
distinct
div
dsave
each, peach
ej
ema
enlist
eval, reval
except
exec
exit
exp, xexp
fby
fills
first, last
fkeys
flip
floor
get, set
getenv, setenv
group
gtime, ltime
hcount
hdel
hopen, hclose
hsym
ij, ijf
in
insert
inter
inv
key
keys, xkey
like
lj, ljf
load, rload
log, xlog
lower
lsq
max, maxs, mmax
md5
med
meta
min, mins, mmin
mmu
mod
neg
next, prev, xprev
not
null
or
over, scan
parse
pj
prd, prds
prior
rand
rank
ratios
raze
read0
read1
reciprocal
reverse
rotate
save, rsave
select
show
signum
sin, asin
sqrt
ss, ssr
string
sublist
sum, sums, msum, wsum
sv
system
tables
tan, atan
til
trim, ltrim, rtrim
type
uj, ujf
union
ungroup
update
upsert
value
var, svar
view, views
vs
where
within
wj, wj1
xbar
xgroup
xrank
Overloaded glyphs
Operators
Operators
Add
Amend
Apply, Index, Trap
Assign
Cast
Coalesce
Compose
Cut
Deal, Roll, Permute
Delete
Display
Dict
Divide
Dynamic Load
Drop
Enkey, Unkey
Enumerate
Enumeration
Enum Extend
Equal
Exec
File Binary
File Text
Fill
Find
Flip Splayed
Greater
Greater Than
Identity, Null
Join
Less Than
Lesser
Match
Matrix Multiply
Multiply
Not Equal
Pad
Select
Set Attribute
Simple Exec
Signal
Subtract
Take
Tok
Update
Vector Conditional
Control constructs
Control constructs
Cond
do
if
while
Namespaces
Namespaces
.h
.j
.m
.Q
.z
Application
Atomic functions
Comparison
Conformability
Connection handles
Datatypes
Dictionaries
Enumerations
Evaluation control
Exposed infrastructure
File system
Function notation
Functional qSQL
Glossary
Internal functions
Joins
Mathematics
Metadata
Namespaces
Parse trees
Parse trees, functional SQL (WP)
QSQL queries
Regular Expressions
Syntax
Tables
Variadic syntax
Database
Database
Tables in the filesystem
Populating tables
Populating tables
Loading from large files
Foreign keys (WP)
Linking columns
Data loaders (WP)
From MDB via ODBC
Persisting tables
Persisting tables
Serializing an object
Splayed tables
Partitioned tables
Segmented databases
Multiple partitions (WP)
Maintenance
Maintenance
Data management (WP)
Data-At-Rest Encryption
File compression
Compression (WP)
Permissions (WP)
Query optimization (WP)
Query scaling (WP)
Time-series simplification (WP)
Compacting HDB sym
Working with sym files (WP)
Developing
Developing
IPC
IPC
Overview
Callbacks
Listening port
Named pipes
Serialization examples
Server calling client
Socket sharding (WP)
SSL/TLS
WebSockets
Interprocess communication (WP)
Tools
Tools
Code profiler
Debugging
Errors
man.q
System commands
Unit tests
Using .z
Coding
Coding
Data visualization (WP)
Deferred response
Geospatial indexing
Linear programming
Multithreaded input
Multithreaded primitives
Pivoting tables
Precision
Programming examples
Programming idioms
Temporal data
Timezones
Unicode
DevOps
DevOps
Authentication and access
Command-line options
CPU affinity
Custom web server
Daemon
Firewalling
inetd, xinetd
Linux production notes
Logging
Multi-threading (WP)
Multiple versions
Parallel processing
Performance tips
Replay logfile
Shebang script
Surveillance latency (WP)
Windows service
Release notes
Release notes
History
Changes in 4.0
Changes in 3.6
Changes in 3.5
Changes in 3.4
Changes in 3.3
Changes in 3.2
Changes in 3.1
Changes in 3.0
Changes in 2.8
Changes in 2.7
Changes in 2.6
Changes in 2.5
Changes in 2.4
Withdrawn
FAQ
Architecture
Architecture
About
Examples
Alternative in-memory layouts
Chained tickerplant
Client-server
Corporate actions
Data recovery for kdb+tick (WP)
Disaster recovery (WP)
Gateway design (WP)
Kdb+tick configuration
Kdb+tick profiling (WP)
Kubernetes
Load balancing
Memory backed by files
Optane Memory
Optane Memory
Optane Memory and kdb+
Performance tests
Order Book (WP)
Publish and subscribe
Pub/sub with Solace (WP)
Query Routing (WP)
Real-time tick subscribers (WP)
WebSockets (WP)
Write-only RDB
Advanced
Advanced
Distributed systems (WP)
Intraday writedown (WP)
Help
Coming soon
¶
Back to top