Files
valkey/tests
Raghav 8a4a7b25dc CLUSTERSCAN Command (#2934)
Implemented CLUSTERSCAN command for topology-aware scanning

Unlike `SCAN` which is local to a single node, `CLUSTERSCAN` provides a
mechanism that helps clients iterate across slot boundaries and handles
`MOVED` redirections.

**Key details**

* Global cluster iteration via `fingerprint-{hashtag}-cursor`
* Scan one slot at a time
* Start the CLUSTERSCAN with 0
* SLOT argument for parallel scanning of multiple slots
* Re-use scanGenericCommand for the response

**Cursor format:** `fingerprint-{hashtag}-localcursor`
 - Fingerprint is a hash of the node's DB seed that identifies the
   current memory layout. On mismatch, scan restarts from cursor 0
   rather than returning an error.
 - Fingerprint 0 indicates a cross slot cursor (e.g., initial cursor
   or slot transition) where validation is skipped.
 - Hashtag encodes the target slot
 - Local cursor tracks position within the slot

**Usage:**

```
CLUSTERSCAN <cursor> [MATCH pattern] [COUNT count] [TYPE type] [SLOT number]
```

```
  CLUSTERSCAN 0                    # Start scanning from slot 0
  CLUSTERSCAN <cursor>             # Continue from cursor
  CLUSTERSCAN 0 SLOT 1000          # Start scanning specific slot
  CLUSTERSCAN <cursor> MATCH user:* COUNT 100
```

---------

Signed-off-by: nmvk <r@nmvk.com>
Signed-off-by: Raghav <r@nmvk.com>
Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
Co-authored-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
2026-03-09 07:41:36 -07:00
..
2026-03-09 07:41:36 -07:00
2026-03-09 07:41:36 -07:00

Valkey Test Suite

Overview

Integration tests are written in Tcl, a high-level, general-purpose, interpreted, dynamic programming language [source]. runtest is the main entrance point for running integration tests. For example, to run a single test;

./runtest --single unit/your_test_name
# For additional arguments, you may refer to the `runtest` script itself.

The normal execution mode of the test suite involves starting and manipulating local valkey-server instances, inspecting process state, log files, etc.

The test suite also supports execution against an external server, which is enabled using the --host and --port parameters. When executing against an external server, tests tagged external:skip are skipped.

There are additional runtime options that can further adjust the test suite to match different external server configurations. All options are listed by ./runtest --help. The following table is just a subset of the options:

Option Impact
--singledb Only use database 0, don't assume others are supported.
--ignore-encoding Skip all checks for specific encoding.
--ignore-digest Skip key value digest validations.
--cluster-mode Run in strict Valkey Cluster compatibility mode.
--large-memory Enables tests that consume more than 100MB
--tls Run tests with TLS. See below.
--tls-module Run tests with TLS, when TLS support is built as a module.
--other-server-path PATH Run compatibility tests with another server executable.
--help Displays the full set of options.

Running with TLS requires the following preparations:

  • Build Valkey is TLS support, e.g. using make BUILD_TLS=yes, or make BUILD_TLS=module.
  • Run ./utils/gen-test-certs.sh to generate a root CA, server certificates, and invalid certificates for testing.
  • Install TLS support for TCL, e.g. the tcl-tls package on Debian/Ubuntu.

Additional tests

Not all tests are included in the ./runtest scripts. Some additional entry points are provided by the following scripts, which support a subset of the options listed above:

  • ./runtest-cluster runs more extensive tests for Valkey Cluster. Some cluster tests are included in ./runtest, but not all.
  • ./runtest-sentinel runs tests of Valkey Sentinel.
  • ./runtests-module runs tests of the module API.

Debugging

You can set a breakpoint and invoke a minimal debugger using the bp function.

... your test code before break-point
bp 1
... your test code after break-point

The bp 1 will give back the tcl interpreter to the developer, and allow you to interactively print local variables (through puts), run functions and so forth [source]. bp takes a single argument, which is 1 for the case above, and is used to label a breakpoint with a string. Labels are printed out when breakpoints are hit, so you can identify which breakpoint was triggered. Breakpoints can be skipped by setting the global variable ::bp_skip, and by providing the labels you want to skip.

The minimal debugger comes with the following predefined functions.

  • Press c to continue past the breakpoint.
  • Press i to print local variables.

Tags

Tags are applied to tests to classify them according to the subsystem they test, but also to indicate compatibility with different run modes and required capabilities.

Tags can be applied in different context levels:

  • start_server context
  • tags context that bundles several tests together
  • A single test context.

Some tags are restricted to top-level use only. These tags are large-memory, needs:other-server, compatible-redis and network.

The following compatibility and capability tags are currently used:

Tag Indicates
external:skip Not compatible with external servers.
cluster Uses cluster with multiple nodes.
cluster:skip Not compatible with --cluster-mode.
large-memory Test that requires more than 100MB
tls Uses TLS.
tls:skip Not compatible with --tls.
ipv6 Uses IPv6.
needs:repl, repl Uses replication and needs to be able to SYNC from server.
needs:debug Uses the DEBUG command or other debugging focused commands (like OBJECT REFCOUNT).
needs:pfdebug Uses the PFDEBUG command.
needs:config-maxmemory Uses CONFIG SET to manipulate memory limit, eviction policies, etc.
needs:config-resetstat Uses CONFIG RESETSTAT to reset statistics.
needs:reset Uses RESET to reset client connections.
needs:save Uses SAVE or BGSAVE to create an RDB file.
needs:other-server Requires --other-server-path.
compatible-redis Tests that run against Redis (compatibility tests).
network Tests that require network operations.
singledb Test runs as if --singledb was given.
valgrind:skip Not compatible with --valgrind.

When using an external server (--host and --port), filtering using the external:skip tags is done automatically.

When using --valgrind, filtering using the valgrind:skip tag is done automatically.

When using --cluster-mode, filtering using the cluster:skip tag is done automatically.

When not using --large-memory, filtering using the largemem:skip tag is done automatically.

In addition, it is possible to specify additional configuration. For example, to run tests on a server that does not permit SYNC use:

./runtest --host <host> --port <port> --tags -needs:repl