Reloading of the RDB generated by
DEBUG POPULATE 5000000
SAVE
is now 25% faster.
This commit also prepares the ability to have more flexibility when
loading stuff from the RDB, since we no longer use dbAdd() but can
control exactly how things are added in the database.
Related to #5145.
Design note: clients may change type when they turn into replicas or are
moved into the Pub/Sub category and so forth. Moreover the recomputation
of the bytes used is problematic for obvious reasons: it changes
continuously, so as a conservative way to avoid accumulating errors,
each client remembers the contribution it gave to the sum, and removes
it when it is freed or before updating it with the new memory usage.
Initially they needed to be at the end so that we could extend to N
strings in the future, but after further consideration I no longer
believe it's worth it.
Example: Client uses a pipe to send the following to a
stale replica:
MULTI
.. do something ...
DISCARD
The replica will reply the MUTLI with -MASTERDOWN and
execute the rest of the commands... A client using a
pipe might not be aware that MULTI failed until it's
too late.
I can't think of a reason why MULTI/EXEC/DISCARD should
not be executed on stale replicas...
Also, enable MULTI/EXEC/DISCARD during loading
By using a "circular BRPOPLPUSH"-like scenario it was
possible the get the same client on db->blocking_keys
twice (See comment in moduleTryServeClientBlockedOnKey)
The fix was actually already implememnted in
moduleTryServeClientBlockedOnKey but it had a bug:
the funxction should return 0 or 1 (not OK or ERR)
Other changes:
1. Added two commands to blockonkeys.c test module (To
reproduce the case described above)
2. Simplify blockonkeys.c in order to make testing easier
3. cast raxSize() to avoid warning with format spec
Makse sure call() doesn't wrap replicated commands with
a redundant MULTI/EXEC
Other, unrelated changes:
1. Formatting compiler warning in INFO CLIENTS
2. Use CLIENT_ID_AOF instead of UINT64_MAX
37a10cef introduced automatic wrapping of MULTI/EXEC for the
alsoPropagate API. However this collides with the built-in mechanism
already present in module.c. To avoid complex changes near Redis 6 GA
this commit introduces the ability to exclude call() MUTLI/EXEC wrapping
for also propagate in order to continue to use the old code paths in
module.c.
propagate_last_id is declared outside of the loop but used
only from within the loop. Once it's '1' it will never go
back to '0' and will replicate XSETID even for IDs that
don't actually change the last_id.
While not a serious bug (XSETID always used group->last_id
so there's no risk), it does causes redundant traffic
between master and its replicas
Now that this mechanism is the sole one used for blocked clients
timeouts, it is more wise to cleanup the table when the client unblocks
for any reason. We use a flag: CLIENT_IN_TO_TABLE, in order to avoid a
radix tree lookup when the client was already removed from the table
because we processed it by scanning the radix tree.
First, we must parse the IDs, so that we abort ASAP.
The return value of this command cannot be an error if
the client successfully acknowledged some messages,
so it should be executed in a "all or nothing" fashion.
the AOF will be loaded successfully, but the stream will be missing,
i.e inconsistencies with the original db.
this was because XADD with id of 0-0 would error.
add a test to reproduce.
A very commonly signaled operational problem with Redis master-replicas
sets is that, once the master becomes unavailable for some reason,
especially because of network problems, many times it wont be able to
perform a partial resynchronization with the new master, once it rejoins
the partition, for the following reason:
1. The master becomes isolated, however it keeps sending PINGs to the
replicas. Such PINGs will never be received since the link connection is
actually already severed.
2. On the other side, one of the replicas will turn into the new master,
setting its secondary replication ID offset to the one of the last
command received from the old master: this offset will not include the
PINGs sent by the master once the link was already disconnected.
3. When the master rejoins the partion and is turned into a replica, its
offset will be too advanced because of the PINGs, so a PSYNC will fail,
and a full synchronization will be required.
Related to issue #7002 and other discussion we had in the past around
this problem.
Redis refusing to run MULTI or EXEC during script timeout may cause partial
transactions to run.
1) if the client sends MULTI+commands+EXEC in pipeline without waiting for
response, but these arrive to the shards partially while there's a busy script,
and partially after it eventually finishes: we'll end up running only part of
the transaction (since multi was ignored, and exec would fail).
2) similar to the above if EXEC arrives during busy script, it'll be ignored and
the client state remains in a transaction.
the 3rd test which i added for a case where MULTI and EXEC are ok, and
only the body arrives during busy script was already handled correctly
since processCommand calls flagTransaction
We assume accept handlers may choose to reject a connection and close
it, but connAccept() callers can't distinguish between this state and
other error states requiring connClose().
This makes it safe (and mandatory!) to always call connClose() if
connAccept() fails, and safe for accept handlers to close connections
(which will defer).
