The implementation of the diskless replication was currently diskless only on the master side.
The slave side was still storing the received rdb file to the disk before loading it back in and parsing it.
This commit adds two modes to load rdb directly from socket:
1) when-empty
2) using "swapdb"
the third mode of using diskless slave by flushdb is risky and currently not included.
other changes:
--------------
distinguish between aof configuration and state so that we can re-enable aof only when sync eventually
succeeds (and not when exiting from readSyncBulkPayload after a failed attempt)
also a CONFIG GET and INFO during rdb loading would have lied
When loading rdb from the network, don't kill the server on short read (that can be a network error)
Fix rdb check when performed on preamble AOF
tests:
run replication tests for diskless slave too
make replication test a bit more aggressive
Add test for diskless load swapdb
Add tests to check basic functionality of this optional keyword, and also tested with
a module (redisgraph). Checked quickly with valgrind, no issues.
Copies name the type name canonicalisation code from `typeCommand`, perhaps this would
be better factored out to prevent the two diverging and both needing to be edited to
add new `OBJ_*` types, but this is a little fiddly with C strings.
The [redis-doc](https://github.com/antirez/redis-doc/blob/master/commands.json) repo
will need to be updated with this new arg if accepted.
A quirk to be aware of here is that the GEO commands are backed by zsets not their own
type, so they're not distinguishable from other zsets.
Additionally, for sparse types this has the same behaviour as `MATCH` in that it may
return many empty results before giving something, even for large `COUNT`s.
CLIENT PAUSE may be used, in other contexts, for a long time making all
the slaves time out. Better for now to be more specific about what
should disable senidng PINGs.
An alternative to that would be to virtually refresh the slave
interactions when clients are paused, however for now I went for this
more conservative solution.
In fast systems "SLOWLOG RESET" is fast enough to don't be logged even
when the time limit is "1" sometimes. Leading to false positives such
as:
[err]: SLOWLOG - can be disabled in tests/unit/slowlog.tcl
Expected '1' to be equal to '0'
Now clients that are ready to be terminated asynchronously are processed
more often in beforeSleep() instead of being processed in serverCron().
This means that the test will not be able to catch the moment the client
was terminated, also note that the 'omem' figure now changes in big
steps, because of the new client output buffers layout.
So we have to change the test range in order to accomodate for that.
Yet the test is useful enough to be worth taking, even if its precision
is reduced by this commit. Probably if we get more problems, a thing
that makes sense is just to check that the limit is < 200k. That's more
than enough actually.
