in ACLSetUserCommandBit, when the command bit overflows, no operation
is performed, so no need clear the USER_FLAG_ALLCOMMANDS flag.
in ACLSetUser, when adding subcommand, we don't need to call
ACLGetCommandID ahead since subcommand may be empty.
This was broken in 1a7cd2c: we identified a crash in the CI, what
was happening before the fix should be like that:
1. The client gets in the async free list.
2. However freeClient() gets called again against the same client
which is a master.
3. The client arrived in freeClient() with the CLOSE_ASAP flag set.
4. The master gets cached, but NOT removed from the CLOSE_ASAP linked
list.
5. The master client that was cached was immediately removed since it
was still in the list.
6. Redis accessed a freed cached master.
This is how the crash looked like:
=== REDIS BUG REPORT START: Cut & paste starting from here ===
1092:S 16 May 2020 11:44:09.731 # Redis 999.999.999 crashed by signal: 11
1092:S 16 May 2020 11:44:09.731 # Crashed running the instruction at: 0x447e18
1092:S 16 May 2020 11:44:09.731 # Accessing address: 0xffffffffffffffff
1092:S 16 May 2020 11:44:09.731 # Failed assertion: (:0)
------ STACK TRACE ------
EIP:
src/redis-server 127.0.0.1:21300(readQueryFromClient+0x48)[0x447e18]
And the 0xffff address access likely comes from accessing an SDS that is
set to NULL (we go -1 offset to read the header).
The context is issue #7205: since the introduction of threaded I/O we close
clients asynchronously by default from readQueryFromClient(). So we
should no longer prevent the caching of the master client, to later
PSYNC incrementally, if such flags are set. However we also don't want
the master client to be cached with such flags (would be closed
immediately after being restored). And yet we want a way to understand
if a master was closed because of a protocol error, and in that case
prevent the caching.
This bug was introduced by a recent change in which readQueryFromClient
is using freeClientAsync, and despite the fact that now
freeClientsInAsyncFreeQueue is in beforeSleep, that's not enough since
it's not called during loading in processEventsWhileBlocked.
furthermore, afterSleep was called in that case but beforeSleep wasn't.
This bug also caused slowness sine the level-triggered mode of epoll
kept signaling these connections as readable causing us to keep doing
connRead again and again for ll of these, which keep accumulating.
now both before and after sleep are called, but not all of their actions
are performed during loading, some are only reserved for the main loop.
fixes issue #7215
This is really required only for older OpenSSL versions.
Also, at the moment Redis does not use OpenSSL from multiple threads so
this will only be useful if modules end up doing that.
We want to send pings and pongs at specific intervals, since our packets
also contain information about the configuration of the cluster and are
used for gossip. However since our cluster bus is used in a mixed way
for data (such as Pub/Sub or modules cluster messages) and metadata,
sometimes a very busy channel may delay the reception of pong packets.
So after discussing it in #7216, this commit introduces a new field that
is not exposed in the cluster, is only an internal information about
the last time we received any data from a given node: we use this field
in order to avoid detecting failures, claiming data reception of new
data from the node is a proof of liveness.
This works because this struct is never referenced by its name,
but always by its type.
This prevents a conflict with struct user from <sys/user.h>
when compiling against uclibc.
Signed-off-by: Titouan Christophe <titouan.christophe@railnova.eu>
* fix memlry leaks with diskless replica short read.
* fix a few timing issues with valgrind runs
* fix issue with valgrind and watchdog schedule signal
about the valgrind WD issue:
the stack trace test in logging.tcl, has issues with valgrind:
==28808== Can't extend stack to 0x1ffeffdb38 during signal delivery for thread 1:
==28808== too small or bad protection modes
it seems to be some valgrind bug with SA_ONSTACK.
SA_ONSTACK seems unneeded since WD is not recursive (SA_NODEFER was removed),
also, not sure if it's even valid without a call to sigaltstack()
Currently, there are several types of threads/child processes of a
redis server. Sometimes we need deeply optimise the performance of
redis, so we would like to isolate threads/processes.
There were some discussion about cpu affinity cases in the issue:
https://github.com/antirez/redis/issues/2863
So implement cpu affinity setting by redis.conf in this patch, then
we can config server_cpulist/bio_cpulist/aof_rewrite_cpulist/
bgsave_cpulist by cpu list.
Examples of cpulist in redis.conf:
server_cpulist 0-7:2 means cpu affinity 0,2,4,6
bio_cpulist 1,3 means cpu affinity 1,3
aof_rewrite_cpulist 8-11 means cpu affinity 8,9,10,11
bgsave_cpulist 1,10-11 means cpu affinity 1,10,11
Test on linux/freebsd, both work fine.
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
When deffered reply is added the previous reply node cannot be used so
all the extra space we allocated in it is wasted. in case someone uses
deffered replies in a loop, each time adding a small reply, each of
these reply nodes (the small string reply) would have consumed a 16k
block.
now when we add anther diferred reply node, we trim the unused portion
of the previous reply block.
see #7123
cherry picked from commit fb732f7a94
with fix to handle a crash with LIBC allocator, which apparently can
return the same pointer despite changing it's size.
i.e. shrinking an allocation of 16k into 56 bytes without changing the
pointer.
We could use uint64_t specific macros, but after all it's simpler to
just use an obvious equivalent type plus casting: this will be a no op
and is simpler than fixed size types printf macros.
1. add eviction-lazyfree monitor
2. put eviction-del & eviction-lazyfree into eviction-cycle
that means eviction-cycle contains all the latency in
the eviction cycle including del and lazyfree
3. use getMaxmemoryState to check if we can break in lazyfree-evict
If client gets blocked again in `processUnblockedClients`, redis will not send
`REPLCONF GETACK *` to slaves untill next eventloop, so the client will be
blocked for 100ms by default(10hz) if no other file event fired.
move server.get_ack_from_slaves sinppet after `processUnblockedClients`, so
that both the first WAIT command that puts client in blocked context and the
following WAIT command processed in processUnblockedClients would trigger
redis-sever to send `REPLCONF GETACK *`, so that the eventloop would get
`REPLCONG ACK <reploffset>` from slaves and unblocked ASAP.
come to think of it, in theory (not in practice), getDecodedObject can
return the same original object with refcount incremented, so the
pointer comparision in the previous commit was invalid.
so now instead of checking the encoding, we explicitly check the
refcount.
since the recent addition of OBJ_STATIC_REFCOUNT and the assertion in
incrRefCount it is now impossible to use dictFind using a static robj,
because dictEncObjKeyCompare will call getDecodedObject which tries to
increment the refcount just in order to decrement it later.
Now both master and replicas keep track of the last replication offset
that contains meaningful data (ignoring the tailing pings), and both
trim that tail from the replication backlog, and the offset with which
they try to use for psync.
the implication is that if someone missed some pings, or even have
excessive pings that the promoted replica has, it'll still be able to
psync (avoid full sync).
the downside (which was already committed) is that replicas running old
code may fail to psync, since the promoted replica trims pings form it's
backlog.
This commit adds a test that reproduces several cases of promotions and
demotions with stale and non-stale pings
Background:
The mearningful offset on the master was added recently to solve a problem were
the master is left all alone, injecting PINGs into it's backlog when no one is
listening and then gets demoted and tries to replicate from a replica that didn't
have any of the PINGs (or at least not the last ones).
however, consider this case:
master A has two replicas (B and C) replicating directly from it.
there's no traffic at all, and also no network issues, just many pings in the
tail of the backlog. now B gets promoted, A becomes a replica of B, and C
remains a replica of A. when A gets demoted, it trims the pings from its
backlog, and successfully replicate from B. however, C is still aware of
these PINGs, when it'll disconnect and re-connect to A, it'll ask for something
that's not in the backlog anymore (since A trimmed the tail of it's backlog),
and be forced to do a full sync (something it didn't have to do before the
meaningful offset fix).
Besides that, the psync2 test was always failing randomly here and there, it
turns out the reason were PINGs. Investigating it shows the following scenario:
cycle 1: redis #1 is master, and all the rest are direct replicas of #1
cycle 2: redis #2 is promoted to master, #1 is a replica of #2 and #3 is replica of #1
now we see that when #1 is demoted it prints:
17339:S 21 Apr 2020 11:16:38.523 * Using the meaningful offset 3929963 instead of 3929977 to exclude the final PINGs (14 bytes difference)
17339:S 21 Apr 2020 11:16:39.391 * Trying a partial resynchronization (request e2b3f8817735fdfe5fa4626766daa938b61419e5:3929964).
17339:S 21 Apr 2020 11:16:39.392 * Successful partial resynchronization with master.
and when #3 connects to the demoted #2, #2 says:
17339:S 21 Apr 2020 11:16:40.084 * Partial resynchronization not accepted: Requested offset for secondary ID was 3929978, but I can reply up to 3929964
so the issue here is that the meaningful offset feature saved the day for the
demoted master (since it needs to sync from a replica that didn't get the last
ping), but it didn't help one of the other replicas which did get the last ping.
STRALGO should be a container for mostly read-only string
algorithms in Redis. The algorithms should have two main
characteristics:
1. They should be non trivial to compute, and often not part of
programming language standard libraries.
2. They should be fast enough that it is a good idea to have optimized C
implementations.
Next thing I would love to see? A small strings compression algorithm.
When deffered reply is added the previous reply node cannot be used so
all the extra space we allocated in it is wasted. in case someone uses
deffered replies in a loop, each time adding a small reply, each of
these reply nodes (the small string reply) would have consumed a 16k
block.
now when we add anther diferred reply node, we trim the unused portion
of the previous reply block.
see #7123
