#  Errors


## Runtime errors


{directory}/q.k. OS reports: No such file or directory

:   Using the environment variable `QHOME` (or `<HOME DIRECTORY>/q` if not set), `q.k` was not found in the directory specified. Check that the `QHOME` environment variable is correctly set to the directory containing `q.k`, which is provided in the kdb+ installation files.

[](){#access}
access

:   Tried to read files above directory, run system commands or failed usr/pwd</td> </tr>

[](){#accp}
accp

:   Tried to accept an incoming TCP/IP connection but failed to do so

[](){#adict}
adict

:   E.g. `d[::]:x`

:   Blocked assignment (`'nyi`)

[](){#arch}
arch

:   E.g.
    ```q
    `:test set til 100
    -17!`:test
    ```

    Tried to load file of wrong endian format

[](){#assign}
assign

:   E.g. `cos:12`

    Tried to redefine a reserved word

[](){#bad-lambda}
bad lambda

:   E.g. `h{select x by x from x}`

    lambda from an older version of kdb+ over IPC that no longer parses

[](){#badmsg}
badmsg

:   Failure in [IPC validator](../releases/ChangesIn2.7.md#ipc-message-validator)

bad meta data in file

:   The compressed file contains corrupt meta data. This can happen if the file was incomplete at the time of reading.

[](){#badtail}
badtail

:   Incomplete transaction at end of file, get good (count;length) with ``-11!(-2;`:file)``

[](){#binary-mismatch}
binary mismatch

:   Wrong process for [code profiler](../kb/profiler.md)

[](){#can't}
can't

:   Only commercially licensed kdb+ instances can encrypt code in a script

[](){#cast}
cast

:   E.g. ``s:`a`b; c:`s$`a`e``

    Value not in enumeration

[](){#close}
close

:   (1) content-length header missing from HTTP response

    (2) handle: n – handle was closed by the remote while a msg was expected

[](){#con}
con

:   qcon client is not supported when kdb+ is in [multithreaded input mode](listening-port.md#multi-threaded-input-mode)

[](){#cond}
cond

:   Even number of arguments to `$` (until V3.6 2018.12.06)

[](){#conn}
conn

:   Too many connections. Max connections was 1022 prior to 4.1t 2023.09.15, otherwise the limit imposed by the operating system (operating system configurable for system/protocol).

[](){#could-not-initialize-ssl}
Could not initialize ssl

:   [`(-26!)[]`](internal.md#-26x-ssl) found SSL/TLS not enabled

[](){#d8}
d8

:   The log had a partial transaction at the end but q couldn’t truncate the file

[](){#decompression-error-at-block-[b]-in}
decompression error at block [b] in [k]

:   Error signalled by underlying decompression routine. Can be due to file corruption or a file that is concurrently being overwritten.

[](){#domain}
domain

:   E.g. `til -1`

    Out of domain

[](){#dup}
dup

:   E.g. `` `a`b xasc flip`a`b`a!()``

    Duplicate column in table (since V3.6 2019.02.19)

[](){#dup-names-for-cols/groups}
dup names for cols/groups

:   E.g. `select a,a by a from t`

    Name collision (since V4.0 2020.03.17)

[](){#elim}
elim

:   E.g. ``((-58?`3) set\:(),`a)$`a``

    Too many enumerations (max: 57)

[](){#empty}
empty

: The paths listed in `par.txt` do not contain any partitions or are inaccessible.

[](){#enable-secondary-threads-via-cmd-line--s-only}
enable secondary threads via cmd line -s only

:   E.g. `\s 4`

    Command line enabled processes for parallel processing

[](){#encryption-lib-unavailable}
encryption lib unavailable

:   E.g. ``-36!(`:kf;"pwd")``

    Failed to load OpenSSL libraries

[](){#expected-response}
expected response

:   One-shot request did not receive response

[](){#failed-to-load-TLS-certificates}
failed to load TLS certificates

:   Started kdb+ [with `-E 1` or `-E 2`](cmdline.md#-e-tls-server-mode) but without SSL/TLS enabled

[](){#from}
from

:   E.g. `select price trade`

    Badly formed select query

[](){#hop}
hop

:   Request to `hopen` a handle fails; includes message from OS

[](){#hwr}
hwr

:   Handle write error, can’t write inside a [`peach`](peach.md)

[](){#IJS}
IJS

:   E.g. `"D=\001"0:"0=hello\0011=world"`

    [Key type](../ref/file-text.md#key-value-pairs) is not `I`, `J`, or `S`.

[](){#insert}
insert

:   E.g. ``t:([k:0 1]a:2 3);`t insert(0;3)``

    Tried to [`insert`](../ref/insert.md) a record with an existing key into a keyed table

[](){#invalid}
invalid

:   E.g. `q -e 3`

    Invalid command-line option value

[](){#invalid-password}
invalid password

:   E.g. ``-36!(`:kf;"pwd")``

    Invalid keyfile password

[](){#\l}
\l

:   Not a [data file](syscmds.md#l-load-file-or-directory)

[](){#length}
length

:   E.g. `()+til 1`

    Arguments do not [conform](conformable.md)

[](){#limit}
limit

:   E.g.`0W#2`

    Tried to generate a list longer than 2<sup>40</sup>-1,
    or serialized object is > 1TB,
    or `'type` if trying to serialize a nested object which has > 2 billion elements,
    or  [Parse errors](#parse-errors)

[](){#load}
load

:   Not a [data file](../ref/load.md)

[](){#loop}
loop

:   E.g. `a::b::a`

:   Dependency loop

[](){#main-thread-only}
main thread only

:   E.g. ``-36!(`:kf;"pwd")``

:   Not executed from main thread

[](){#match}
match

:   E.g.
    ```q
    (1):2
    (1 2!(one;two)):1 3!"ac"
    ```
:   [Pattern match](pattern.md) encountered a non-matching value or missing key

[](){#mismatch}
mismatch

:   E.g. `([]a:til 4),([]b:til 3)`

:   Columns that can’t be aligned for `R,R` or `K,K`

[](){#mlim}
mlim

:   Too many nested columns in [splayed tables](../kb/splayed-tables.md).
    (Prior to V3.0, limited to 999; from V3.0, 251; from V3.3, 65530)

[](){#mq}
mq

:   Multi-threading not allowed

[](){#name-too-long}
name too long

:   Filepath ≥100 chars (until V3.6 2018.09.26)

[](){#need-zlib-to-compress}
need zlib to compress

:   zlib not available. [Install zlib libraries](../kb/file-compression.md#gzip) if ability to compress or decompress gzip is required.

[](){#noamend}
noamend

:   E.g.
    ```q
    t:([]a:1 2 3)
    n:`a`b`c
    update b:{`n?`d;:`n?`d}[] from `t
    ```

:   Cannot change global state from within an amend

[](){#no-append-to-zipped-enums}
no append to zipped enums

:   E.g. `` `:sym?`c``

:   Cannot append to zipped enum (from V3.0)

[](){#no-`g#}
no `` `g#``

:   E.g. ``{`g#x}peach 2#enlist 0 1``

:    A thread other than the main q thread has attempted to add a group [attribute](syntax.md#attributes) to a vector.
    Seen with [`peach`](peach.md)+secondary threads or multithreaded input queue

[](){#noupdate}
noupdate

:   E.g. `{a::x}peach 0 1`

:    Updates blocked by the [`-b` cmd line arg](cmdline.md#-b-blocked),
    or [`reval`](../ref/eval.md#reval) code or a thread other than the main thread has attempted to update a global variable
    when in [`peach`](peach.md)+secondary threads or multithreaded input queue.
    Update not allowed when using [negative port number](syscmds.md#p-listening-port).

[](){#nosocket}
nosocket

:   Can only open or use sockets in main thread.

[](){#nyi}
nyi

:   E.g. `"a"like"**"`

:   Not yet implemented: it probably makes sense, but it’s not defined nor implemented, and needs more thinking about as the language evolves

[](){#os}
os

:   E.g. `\foo bar`

:   Operating-system error or [license error](#license-errors)

[](){#par}
par

:   Unsupported operation on a partitioned table or component thereof

[](){#parse}
parse

:   Invalid [syntax](syntax.md); bad IPC header; or bad binary data in file

[](){#part}
part

:   Something wrong with the partitions in the HDB; or [`med`](../ref/med.md) applied over partitions or segments

[](){#path-too-long}
path too long

:   E.g. ``(`$":",1000#"a") set 1 2 3``

:   File path ≥255 chars (100 before V3.6 2018.09.26)

[](){#PKCS5_PBKDF2_HMAC}
PKCS5_PBKDF2_HMAC

:   E.g. ``-36!(`:kf;"pwd")``

:    Library invocation failed

[](){#pread}
pread

:   Issue reading a compressed file. This can happen if file corrupt or modified during read.

[](){#pwuid}
pwuid

:   OS is missing libraries for `getpwuid`.
    (Most likely 32-bit app on 64-bit OS. Try to [install ia32-libs](../learn/install.md).)

:   or

:   UID (user id) not found in system database of users (e.g. running on container with randomized UID).
    To prevent this issue (since 4.1t 2023.05.26,4.0 2023.11.03) system environment variable HOME or USER can be set to home directory for the user.

[](){#Q7}
Q7

:   nyi op on file nested array

[](){#rank}
rank

:   E.g. `+[2;3;4]`

:   Invalid [rank](glossary.md#rank)

[](){#rb}
rb

:   Encountered a problem while doing a blocking read

[](){#restricted}
restricted

:   E.g. `0"2+3"` in a kdb+ process which was started with [`-b` cmd line](cmdline.md#-b-blocked).

:   Also for a kdb+ process using the username:password authentication file,
    or the `-b` cmd line option, `\x` cannot be used to reset handlers to their default.
    e.g. `\x .z.pg`

[](){#s-fail}
s-fail

:   E.g. `` `s#3 2``

:   Invalid attempt to set sorted [attribute](../ref/set-attribute.md).
    Also encountered with `` `s#enums`` when loading a database (`\l db`) and enum target is not already loaded.

[](){#splay}
splay

:   nyi op on [splayed table](../kb/splayed-tables.md)

[](){#stack}
stack

:   E.g. `{.z.s[]}[]`

:   Ran out of stack space.
    Consider using [Converge `\` `/`](../ref/accumulators.md#unary-values) instead of recursion.

[](){#step}
step

:   E.g. ``d:`s#`a`b!1 2;`d upsert `c`d!3 4``

    Tried to upsert a step dictionary in place

[](){#stop}
stop

:   Current operation stopped due to user interrupt (Ctrl-c) or [time limit (`-T`)](cmdline.md#-t-timeout)

[](){#stype}
stype

:   E.g. `'42`

:   Invalid [type](datatypes.md) used for [Signal](../ref/signal.md)

[](){#sys}
sys

:   E.g. `{system "ls"}peach 0 1`

:   Using system call from thread other than main thread

[](){#threadview}
threadview

:   Trying to calc a [view](../learn/views.md) in a thread other than main thread. A view can be calculated in the main thread only. The cached result can be used from other threads.

[](){#timeout}
timeout

:   Request to `hopen` a handle fails on a timeout; includes message from OS

[](){#TLS-not-enabled}
TLS not enabled

:   Received a TLS connection request, but kdb+ not [started with `-E 1` or `-E 2`](cmdline.md#-e-tls-server-mode)

[](){#too-many-syms}
too many syms

:   kdb+ currently allows for about 1.4B interned symbols in the pool
    and will exit with this error when this threshold is reached

[](){#trunk}
trunc

:   The log had a partial transaction at the end but q couldn’t truncate the file

[](){#type}
type

:   E.g. `til 2.2`

:   Wrong [type](datatypes.md). Also see `limit`

[](){#type/attr-error-amending-file}
type/attr error amending file

:   Direct update on disk for this type or attribute is not allowed

[](){#u-fail}
u-fail

:   E.g. `` `u#2 2``

:   Invalid attempt to set unique or parted [attribute](../ref/set-attribute.md)

[](){#unmappable}
unmappable

:   E.g.
    ```q
    t:([]sym:`a`b;a:(();()))
    .Q.dpft[`:thdb;.z.d;`sym;`t]
    ```

:   When saving partitioned data each column must be mappable. `()` and `("";"";"")` are OK

[](){#unrecognized-key-format}
unrecognized key format

:   E.g. ``-36!(`:kf;"pwd")``

:   Master keyfile format not recognized

[](){#upd}
upd

:   Function `upd` is undefined (sometimes encountered during ``-11!`:logfile``) _or_ [license error](#license-errors)

[](){#utf8}
utf8

:   The websocket requires that text is UTF-8 encoded

[](){#value}
value

:   No value

[](){#vd1}
vd1

:   Attempted multithread update

[](){#view}
view

:   Tried to re-assign a [view](../learn/views.md) to something else

[](){#-w-abort}
-w abort

:   [`malloc`](https://en.wikipedia.org/wiki/C_dynamic_memory_allocation) hit [`-w` limit](cmdline.md#-w-workspace) or [`\w` limit](syscmds.md#w-workspace)

[](){#-w-init-via-cmd-line}
-w init via cmd line

:   Trying to allocate memory with [`\w`](syscmds.md#w-workspace) without `-w` on command line

[](){#wsfull}
wsfull

:   E.g. `999999999#0`

:   [`malloc`](https://en.wikipedia.org/wiki/C_dynamic_memory_allocation) failed, or ran out of swap (or addressability on 32-bit).
    The params also reported are intended to help KX diagnose when assisting clients, and are subject to change.

[](){#wsm}
wsm

:   E.g. `010b wsum 010b`

:   Alias for `nyi` for `wsum` prior to V3.2

[](){#XXX}
XXX

:   E.g. `delete x from system "d";x`

:   Value error (`XXX` undefined)


## System errors

From file ops and [IPC](ipc.md)

error        | explanation
-------------|------------
[](){#Bad-CPU-Type}Bad CPU Type | Tried to run 32-bit interpreter in macOS 10.15+
[](){#XXX:YYY}`XXX:YYY`    | `XXX` is from kdb+, `YYY` from the OS

`XXX` from addr, close, conn, p(from `-p`), snd, rcv or (invalid) filename, e.g. ``read0`:invalidname.txt``


## Parse errors
On execute or load

error | example / explanation
------|----------------------
`[({])}"` | `"hello`

Open `([{` or `"`
[](){#branch}branch | `a:"1;",65024#"0;"`
`value "{if[",a,"]}"`

A branch (`if`;`do`;`while`;`$[.;.;.]`) more than 65025 byte codes away
(255 before V3.6 2017.09.26)
[](){#char}char | `value "\000"`

Invalid character (watch out for non-breaking spaces in copied expressions)
[](){#globals}globals | `a:"::a"sv string til 111;`
`value"{a",a,"::0}"`

Too many [global variables](function-notation.md#variables-and-constants)
limit | `a:";"sv string 2+til 241;`
`value"{",a,"}"`

Too many [constants](function-notation.md#variables-and-constants), or  [limit error](#runtime-errors)
[](){#locals}locals | `a:":a"sv string til 111;`
`value"{a",a,":0}"`

Too many [local variables](function-notation.md#variables-and-constants)
[](){#params}params | `f:{[a;b;c;d;e;f;g;h;e]}`

Too many parameters (8 max)


## License errors
On launch

error | explanation
------|------------
{timestamp} couldn't connect to license daemon | Could not connect to KX license server ([kdb+ On Demand](../learn/licensing.md#licensing-server))
[](){#cores}cores | The license is for [fewer cores than available](../learn/licensing.md#core-restrictions)
[](){#cpu}cpu | The license is for fewer CPUs than available
[](){#exp}exp | License expiry date is prior to system date. The license has expired. Commercial license holders should have their Designated Contacts reach out to licadmin@kx.com or contact sales@kx.com to begin a new commercial agreement.
[](){#host}host | The hostname reported by the OS does not match the hostname or hostname-pattern in the license.

If you see `255.255.255.255` in the kdb+ banner, the machine likely cannot resolve its hostname to an IP address, which will cause a `host` error.

Since 4.1t 2022.07.01,4.0 2022.07.01 the detected hostname is printed. It can be used to compare with the hostname used within the license.
[](){#k4.lic}k4.lic | `k4.lic` file not found. If the environment variable [`QLIC`](../learn/licensing.md#keeping-the-license-key-file-elsewhere) is set, check it is set to the directory containing the license file. **Note** that it should not be set to the location of the license file itself, but to the directory that contains the license file.  If `QLIC` is not set, check that the directory specified by the environment variables [`QHOME`](../learn/install.md#step-2-unzip-your-download) contains the license file.
[](){#os}os | Wrong OS or operating-system error (if runtime error)
[](){#srv}srv | Client-only license in server mode
[](){#upd}upd | Version of kdb+ more recent than update date, _or_ the function `upd` is undefined (sometimes encountered during ``-11!`:logfile``)
[](){#user}user | Unlicensed user
[](){#wha}wha | System date is prior to kdb+ version date. Check that the system date shows the correct date.
[](){#wrong-q.k-version}wrong q.k version | `q` and `q.k` versions do not match. Check that the `q.k` file found in the directory specified by the `QHOME` environment variable is the same version as that supplied with the q binary.


License-related errors are reported with the prefix `licence error: ` since V4.0 2019.10.22.


[Licensing](../learn/licensing.md)


## Handling errors

Use system command [`\` (abort)](syscmds.md#terminate) to clear one level off the execution stack.

Keyword [`exit`](../ref/exit.md) terminates the kdb+ process.

Use hook [`.z.exit`](../ref/dotz.md#zexit-action-on-exit) to set a callback on process exit.

Use [Signal](../ref/signal.md) to signal errors.

Use [Trap and Trap At](../ref/apply.md#trap) to trap errors.


[Debugging](debug.md)