guybe7 3c3e6cc1c7
X[AUTO]CLAIM should skip deleted entries (#10227)
Fix #7021 #8924 #10198

# Intro
Before this commit X[AUTO]CLAIM used to transfer deleted entries from one
PEL to another, but reply with "nil" for every such entry (instead of the entry id).
The idea (for XCLAIM) was that the caller could see this "nil", realize the entry
no longer exists, and XACK it in order to remove it from PEL.
The main problem with that approach is that it assumes there's a correlation
between the index of the "id" arguments and the array indices, which there
isn't (in case some of the input IDs to XCLAIM never existed/read):

```
127.0.0.1:6379> XADD x 1 f1 v1
"1-0"
127.0.0.1:6379> XADD x 2 f1 v1
"2-0"
127.0.0.1:6379> XADD x 3 f1 v1
"3-0"
127.0.0.1:6379> XGROUP CREATE x grp 0
OK
127.0.0.1:6379> XREADGROUP GROUP grp Alice COUNT 2 STREAMS x >
1) 1) "x"
   2) 1) 1) "1-0"
         2) 1) "f1"
            2) "v1"
      2) 1) "2-0"
         2) 1) "f1"
            2) "v1"
127.0.0.1:6379> XDEL x 1 2
(integer) 2
127.0.0.1:6379> XCLAIM x grp Bob 0 0-99 1-0 1-99 2-0
1) (nil)
2) (nil)
```

# Changes
Now,  X[AUTO]CLAIM acts in the following way:
1. If one tries to claim a deleted entry, we delete it from the PEL we found it in
  (and the group PEL too). So de facto, such entry is not claimed, just cleared
  from PEL (since anyway it doesn't exist in the stream)
2. since we never claim deleted entries, X[AUTO]CLAIM will never return "nil"
  instead of an entry.
3. add a new element to XAUTOCLAIM's response (see below)

# Knowing which entries were cleared from the PEL
The caller may want to log any entries that were found in a PEL but deleted from
the stream itself (it would suggest that there might be a bug in the application:
trimming the stream while some entries were still no processed by the consumers)

## XCLAIM
the set {XCLAIM input ids} - {XCLAIM returned ids} contains all the entry ids that were
not claimed which means they were deleted (assuming the input contains only entries
from some PEL). The user doesn't need to XACK them because XCLAIM had already
deleted them from the source PEL.

## XAUTOCLAIM
XAUTOCLAIM has a new element added to its reply: it's an array of all the deleted
stream IDs it stumbled upon.

This is somewhat of a breaking change since X[AUTO]CLAIM used to be able to reply
with "nil" and now it can't... But since it was undocumented (and generally a bad idea
to rely on it, as explained above) the breakage is not that bad.
2022-02-08 10:20:09 +02:00
..

Redis Test Suite

The normal execution mode of the test suite involves starting and manipulating local redis-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:

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 Redis Cluster compatibility mode.
--large-memory Enables tests that consume more than 100mb

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.

The following compatibility and capability tags are currently used:

Tag Indicates
external:skip Not compatible with external servers.
cluster:skip Not compatible with --cluster-mode.
large-memory Test that requires more than 100mb
tls:skip Not campatible with --tls.
needs: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).
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 to create an RDB file.

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