Starting redis 6.0 (part of the TLS feature), diskless master uses pipe from the fork
child so that the parent is the one sending data to the replicas.
This mechanism has an issue in which a hung replica will cause the master to wait
for it to read the data sent to it forever, thus preventing the fork child from terminating
and preventing the creations of any other forks.
This PR adds a timeout mechanism, much like the ACK-based timeout,
we disconnect replicas that aren't reading the RDB file fast enough.
* Modules API docs: Link API function names to their definitions
Occurrences of API functions are linked to their definition.
A function index with links to all functions is added on the bottom
of the page.
Comment blocks in module.c starting with a markdown h2 heading are
used as sections. A table of contents is generated from these
headings.
The functions names are changed from h2 to h3, since they are now
rendered as sub-headings within each section.
Existing sections in module.c are used with some minor changes.
Some documentation text is added or sligtly modified.
The markdown renderer will add IDs which may clash with our
generated IDs. By prefixing section IDs with "section-" we make
them different.
Replace double dashes with a unicode long ndash
In a code example, using RedisModule_FreeString instead of
RedisModule_Free makes it behave correctly regardless of whether
automatic memory is used or not.
server.client_pause_end_time is uninitialized, or actually 0, at startup,
which means this method would think the timeout was reached
and go look for paused clients.
This causes no harm since unpauseClients will not find any paused clients.
The code used to decide on the next time to wake on a timer with
microsecond accuracy, but when deciding to go to sleep it used
milliseconds accuracy (with truncation), this means that it would wake
up too early, see that there's no timer to process, and go to sleep
again for 0ms again and again until the right microsecond arrived.
i.e. a timer for 100ms, would sleep for 99ms, but then do a busy loop
through the kernel in the last millisecond, triggering many calls to
beforeSleep.
The fix is to change all the logic in ae.c to work with microseconds,
which is good since most of the ae backends support micro (or even nano)
seconds. however the epoll backend, doesn't support micro, so to avoid
this problem it needs to round upwards, rather than truncate.
Issue created by the monotonic timer PR #7644 (redis 6.2)
Before that, all the timers in ae.c were in milliseconds (using
mstime), so when it requested the backend to sleep till the next timer
event, it would have worked ok.
The bio aof fsync fd may be closed by main thread (AOFRW done handler)
and even possibly reused for another socket, pipe, or file.
This can can an EBADF or EINVAL fsync error, which will lead to -MISCONF errors failing all writes.
We just ignore these errno because aof fsync did not really fail.
We handle errno when fsyncing aof in bio, so we could know the real reason
when users get -MISCONF Errors writing to the AOF file error
Issue created with #8419
Fix out of range error messages to be clearer (avoid mentioning 9223372036854775807)
* Fix XAUTOCLAIM COUNT option confusing error msg
* Fix other RPOP and alike error message to mention positive
With this fix, module data type registration will fail if the load or save callbacks are not defined, or the optional aux load and save callbacks are not either both defined or both missing.
Background:
Redis 6.2 added ACL control for pubsub channels (#7993), which were supposed
to be permissive by default to retain compatibility with redis 6.0 ACL.
But due to a bug, only newly created users got this `acl-pubsub-default` applied,
while overwritten (updated) users got reset to `resetchannels` (denied).
Since the "default" user exists before loading the config file,
any ACL change to it, results in an update / overwrite.
So when a "default" user is loaded from config file or include ACL
file with no channels related rules, the user will not have any
permissions to any channels. But other users will have default
permissions to any channels.
When upgraded from 6.0 with config rewrite, this will lead to
"default" user channels permissions lost.
When users are loaded from include file, then call "acl load", users
will also lost channels permissions.
Similarly, the `reset` ACL rule, would have reset the user to be denied
access to any channels, ignoring `acl-pubsub-default` and breaking
compatibility with redis 6.0.
The implication of this fix is that it regains compatibility with redis 6.0,
but breaks compatibility with redis 6.2.0 and 2.0.1. e.g. after the upgrade,
the default user will regain access to pubsub channels.
Other changes:
Additionally this commit rename server.acl_pubusub_default to
server.acl_pubsub_default and fix typo in acl tests.
Previously (and by default after commit) when master loose its last slot
(due to migration, for example), its replicas will migrate to new last slot
holder.
There are cases where this is not desired:
* Consolidation that results with removed nodes (including the replica, eventually).
* Manually configured cluster topologies, which the admin wishes to preserve.
Needlessly migrating a replica triggers a full synchronization and can have a negative impact, so
we prefer to be able to avoid it where possible.
This commit adds 'cluster-allow-replica-migration' configuration option that is
enabled by default to preserve existed behavior. When disabled, replicas will
not be auto-migrated.
Fixes#4896
Co-authored-by: Oran Agra <oran@redislabs.com>
In `aof.c`, we call fsync when stop aof, and now print a log to let user know that if fail.
In `cluster.c`, we now return error, the calling function already handles these write errors.
In `redis-cli.c`, users hope to save rdb, we now print a message if fsync failed.
In `rio.c`, we now treat fsync errors like we do for write errors.
In `server.c`, we try to fsync aof file when shutdown redis, we only can print one log if fail.
In `bio.c`, if failing to fsync aof file, we will set `aof_bio_fsync_status` to error , and reject writing just like last writing aof error, moreover also set INFO command field `aof_last_write_status` to error.
This command used to return the last scanned entry id as the cursor,
instead of the next one to be scanned.
so in the next call, the user could / should have sent `(cursor` and not
just `cursor` if he wanted to avoid scanning the same record twice.
Scanning the record twice would look odd if someone is checking what
exactly was scanned, but it also has a side effect of incrementing the
delivery count twice.
If GT/LT fails the operation we need to reply with
nill (like failure due to NX).
Other changes:
Add the missing $encoding suffix to many zset tests
Note: there's a behavior change just in case of INCR + GT/LT that fails.
The old code was replying with the wrong (rejected) score, and now it'll reply with nil.
Note that that's anyway a corner case so this "behavior change" shouldn't have too much affect.
Using GT/LT with INCR has a predictable result even before we run the command
(INCR GT will only only / always fail if the increment is negative).
The implications of this change is just that in the past when a config file was missing,
in some cases it was exiting before printing the sever startup prints and sometimes after,
and now it'll always exit before printing them.
There are 2 common range comparators for skiplist: zslValueGteMin and
zslValueLteMax, but they're not being reused in zslDeleteRangeByScore
This is a small change to make code cleaner.
this is a followup PR for #8699
instead of copying the deferred reply data to the previous node only if it has room for the entire thing,
we can now split the new payload, put part of it into the spare space in the prev node,
and the rest may fit into the next node.
