In order to support the use of multi-exec in pipeline, it is important that
MULTI and EXEC are never rejected and it is easy for the client to know if the
connection is still in multi state.
It was easy to make sure MULTI and DISCARD never fail (done by previous
commits) since these only change the client state and don't do any actual
change in the server, but EXEC is a different story.
Since in the past, it was possible for clients to handle some EXEC errors and
retry the EXEC, we now can't affort to return any error on EXEC other than
EXECABORT, which now carries with it the real reason for the abort too.
Other fixes in this commit:
- Some checks that where performed at the time of queuing need to be re-
validated when EXEC runs, for instance if the transaction contains writes
commands, it needs to be aborted. there was one check that was already done
in execCommand (-READONLY), but other checks where missing: -OOM, -MISCONF,
-NOREPLICAS, -MASTERDOWN
- When a command is rejected by processCommand it was rejected with addReply,
which was not recognized as an error in case the bad command came from the
master. this will enable to count or MONITOR these errors in the future.
- make it easier for tests to create additional (non deferred) clients.
- add tests for the fixes of this commit.
the recent change in that loop (iteration rather than waiting for it to
be empty) was intended to avoid an endless loop in case some slave would
refuse to be freed.
but the lookup of the first client remained, which would have caused it
to try the first one again and again instead of moving on.
Much like MULTI/EXEC/DISCARD, the WATCH and UNWATCH are not actually
operating on the database or server state, but instead operate on the
client state. the client may send them all in one long pipeline and check
all the responses only at the end, so failing them may lead to a
mismatch between the client state on the server and the one on the
client end, and execute the wrong commands (ones that were meant to be
discarded)
the watched keys are not actually stored in the client struct, but they
are in fact part of the client state. for instance, they're not cleared
or moved in SWAPDB or FLUSHDB.
Now it is also possible for ACL SETUSER to accept empty strings
as valid operations (doing nothing), so for instance
ACL SETUSER myuser ""
Will have just the effect of creating a user in the default state.
This should fix#7329.
these tests create several edge cases that are otherwise uncovered (at
least not consistently) by the test suite, so although they're no longer
testing what they were meant to test, it's still a good idea to keep
them in hope that they'll expose some issue in the future.
i.e. don't start the search from scratch hitting the used ones again.
this will also reduce the likelihood of collisions (if there are any
left) by increasing the time until we re-use a port we did use in the
past.
This impacts client verification for chained certificates (such as Lets
Encrypt certificates). Client Verify requires the full chain in order to
properly verify the certificate.
After a closer look, the Redis core devleopers all believe that this was
too fragile, caused many bugs that we didn't expect and that were very
hard to track. Better to find an alternative solution that is simpler.
We want to react a bit more aggressively if we sense that the master is
sending us some corrupted stream. By setting the protocol error we both
ensure that the replica will disconnect, and avoid caching the master so
that a full SYNC will be required. This is protective against
replication bugs.
`clusterStartHandshake` will start hand handshake
and eventually send CLUSTER MEET message, which is strictly prohibited
in the REDIS CLUSTER SPEC.
Only system administrator can initiate CLUSTER MEET message.
Futher, according to the SPEC, rather than IP/PORT pairs, only nodeid
can be trusted.
apparently when running tests in parallel (the default of --clients 16),
there's a chance for two tests to use the same port.
specifically, one test might shutdown a master and still have the
replica up, and then another test will re-use the port number of master
for another master, and then that replica will connect to the master of
the other test.
this can cause a master to count too many full syncs and fail a test if
we run the tests with --single integration/psync2 --loop --stop
see Probmem 2 in #7314
