lookupKeyReadOrReply and lookupKeyWriteOrReply might decide to reply to the user
with the given robj reply. This reply might be an error reply and if so addReply
function is used instead of addReplyErrorObject which will cause the error reply not
to be counted on stats. The fix checks the first char in the reply and if its '-' (error)
it uses addReplyErrorObject.
lookupKeyReadOrReply and lookupKeyWriteOrReply might decide to reply to the user
with the given robj reply. This reply might be an error reply and if so addReply
function is used instead of addReplyErrorObject which will cause the error reply not
to be counted on stats. The fix checks the first char in the reply and if its '-' (error)
it uses addReplyErrorObject.
REDISMODULE_CTX_FLAGS_EVICT and REDISMODULE_CTX_FLAGS_MAXMEMORY
shouldn't be set when the module is run inside a replica that doesn't do eviction.
one may argue that the database is under eviction (the master does eviction and sends DELs to the replica).
but on the other hand, we don't really know the master's configuration.
all that matters is if the current instance does evictions or not.
REDISMODULE_CTX_FLAGS_EVICT and REDISMODULE_CTX_FLAGS_MAXMEMORY
shouldn't be set when the module is run inside a replica that doesn't do eviction.
one may argue that the database is under eviction (the master does eviction and sends DELs to the replica).
but on the other hand, we don't really know the master's configuration.
all that matters is if the current instance does evictions or not.
listenToPort attempts to gracefully handle and ignore certain errors but does not store errno prior to logging, which in turn calls several libc functions that may overwrite errno.
This has been discovered due to libmusl strftime() always returning with errno set to EINVAL, which resulted with docker-library/redis#273.
listenToPort attempts to gracefully handle and ignore certain errors but does not store errno prior to logging, which in turn calls several libc functions that may overwrite errno.
This has been discovered due to libmusl strftime() always returning with errno set to EINVAL, which resulted with docker-library/redis#273.
1. moduleReplicateMultiIfNeeded should use server.in_eval like
moduleHandlePropagationAfterCommandCallback
2. server.in_eval could have been set to 1 and not reset back
to 0 (a lot of missed early-exits after in_eval is already 1)
Note: The new assertions in processCommand cover (2) and I added
two module tests to cover (1)
Implications:
If an EVAL that failed (and thus left server.in_eval=1) runs before a module
command that replicates, the replication stream will contain MULTI (because
moduleReplicateMultiIfNeeded used to check server.lua_caller which is NULL
at this point) but not EXEC (because server.in_eval==1)
This only affects modules as module.c the only user of server.in_eval.
Affects versions 6.2.0, 6.2.1
1. moduleReplicateMultiIfNeeded should use server.in_eval like
moduleHandlePropagationAfterCommandCallback
2. server.in_eval could have been set to 1 and not reset back
to 0 (a lot of missed early-exits after in_eval is already 1)
Note: The new assertions in processCommand cover (2) and I added
two module tests to cover (1)
Implications:
If an EVAL that failed (and thus left server.in_eval=1) runs before a module
command that replicates, the replication stream will contain MULTI (because
moduleReplicateMultiIfNeeded used to check server.lua_caller which is NULL
at this point) but not EXEC (because server.in_eval==1)
This only affects modules as module.c the only user of server.in_eval.
Affects versions 6.2.0, 6.2.1
On a replica we do accept connections, even though commands accessing
the database will operate in read-only mode. But the server is still
already operational and processing commands.
Not sending the readiness notification means that on a HA setup where
the nodes all start as replicas (with replicaof in the config) with
a replica that cannot connect to the master server and which might not
come back in a predictable amount of time or at all, the service
supervisor will end up timing out the service and terminating it, with
no option to promote it to be the main instance. This seems counter to
what the readiness notification is supposed to be signaling.
Instead send the readiness notification when we start accepting
commands, and then send the various server status changes as that.
Fixes: commit fb25e68f91045830c7239f3bd3eff1d84f572fa4
Fixes: commit eaf450c3011c2a28ac2b885bed677539115e837b
On a replica we do accept connections, even though commands accessing
the database will operate in read-only mode. But the server is still
already operational and processing commands.
Not sending the readiness notification means that on a HA setup where
the nodes all start as replicas (with replicaof in the config) with
a replica that cannot connect to the master server and which might not
come back in a predictable amount of time or at all, the service
supervisor will end up timing out the service and terminating it, with
no option to promote it to be the main instance. This seems counter to
what the readiness notification is supposed to be signaling.
Instead send the readiness notification when we start accepting
commands, and then send the various server status changes as that.
Fixes: commit 641c64ada10404356fc76c0b56a69b32c76f253c
Fixes: commit dfb598cf3304818e608ceb6b5d9529a293345c4a
