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>
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, ormake BUILD_TLS=module. - Run
./utils/gen-test-certs.shto generate a root CA, server certificates, and invalid certificates for testing. - Install TLS support for TCL, e.g. the
tcl-tlspackage 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-clusterruns more extensive tests for Valkey Cluster. Some cluster tests are included in./runtest, but not all../runtest-sentinelruns tests of Valkey Sentinel../runtests-moduleruns 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
cto continue past the breakpoint. - Press
ito 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_servercontexttagscontext 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