It seeems that since I added the creation of the jemalloc thread redis
sometimes fails to start with the following error:
Inconsistency detected by ld.so: dl-tls.c: 493: _dl_allocate_tls_init: Assertion `listp->slotinfo[cnt].gen <= GL(dl_tls_generation)' failed!
This seems to be due to a race bug in ld.so, in which TLS creation on the
thread, collide with dlopen.
Move the creation of BIO and jemalloc threads to after modules are loaded.
plus small bugfix when trying to disable the jemalloc thread at runtime
This is what happened:
1. Instance starts, is a slave in the cluster configuration, but
actually server.masterhost is not set, so technically the instance
is acting like a master.
2. loadDataFromDisk() calls replicationCacheMasterUsingMyself() even if
the instance is a master, in the case it is logically a slave and the
cluster is enabled. So now we have a cached master even if the instance
is practically configured as a master (from the POV of
server.masterhost value and so forth).
3. clusterCron() sees that the instance requires to replicate from its
master, because logically it is a slave, so it calls
replicationSetMaster() that will in turn call
replicationCacheMasterUsingMyself(): before this commit, this call would
overwrite the old cached master, creating a memory leak.
Calling XADD with 0-0 or 0 would result in creating an
empty key and storing it in the database.
Even worse, because XADD will reply with error the action
will not be replicated, creating a master-replica
inconsistency
loading flag was missing from docs, and fork chidl indicator was removed from
the code but left int he doc and header, re-adding it to the doc together with
the missing function that was needed for it to work.
One problem with the solution proposed so far in #6537 is that key
lookups outside a command execution via call(), still used a cached
time. The cached time needed to be refreshed in multiple places,
especially because of modules callbacks from timers, cluster bus, and
thread safe contexts, that may use RM_Open().
In order to avoid this problem, this commit introduces the ability to
detect if we are inside call(): this way we can use the reference fixed
time only when we are in the context of a command execution or Lua
script, but for the asynchronous lookups, we can still use mstime() to
get a fresh time reference.
After the thread in #6537 and thanks to the suggestions received, this
commit updates the original patch in order to:
1. Solve the problem of updating the time in multiple places by updating
it in call().
2. Avoid introducing a new field but use our cached time.
This required some minor refactoring to the function updating the time,
and the introduction of a new cached time in microseconds in order to
use less gettimeofday() calls.
Calling lookupKey*() many times to search a key in one command
may get different result.
That's because lookupKey*() calls expireIfNeeded(), and delete
the key when reach the expire time. So we can get an robj before
the expire time, but a NULL after the expire time.
The worst is that may lead to Redis crash, for example
`RPOPLPUSH foo foo` the first time we get a list form `foo` and
hold the pointer, but when we get `foo` again it's expired and
deleted. Now we hold a freed memory, when execute rpoplpushHandlePush()
redis crash.
To fix it, we can refactor the judgment about whether a key is expired,
using the same basetime `server.cmd_start_mstime` instead of calling
mstime() everytime.
See #6525, this likely creates a NULL deference if the client was
terminated by Redis between the creation of the blocked client and the
creation of the thread safe context.
When implementing the code that saves and loads these aux fields we used rdb
format that was added for that in redis 5.0, but then we added the 'when' field
which meant that the old redis-check-rdb won't be able to skip these.
this fix adds an opcode as if that 'when' is part of the module data.
(cherry picked from commit 3bfcae247a)
Before this commit we may have not consumer buffers when a read error is
encountered. Such buffers may contain errors that are important clues
for the user: for instance a protocol error in the payload we send in
pipe mode will cause the server to abort the connection. If the user
does not get the protocol error, debugging what is happening can be a
nightmare.
This commit fixes issue #3756.
Khem Raj