Maksim Kaitmazian authored 2 months ago and Dmitry Rodionov committed 2 months ago

Previously, using a default port of another protocol would result in an
error like the following
```
error: Invalid value "localhost:8080" for '--pg-listen <[HOST][:PORT]>': PGPROTO cannot listen on port 8080 because it is default port for HTTP
```

This commit allows default ports to be used by other protocols,
as long as the port is not already occupied.

Close #1254

The bug was introduced when I changed the behaviour of conf_change in
regard to instances with target_state Expelled. As a result we would
sometimes arbitrarily demote healthy voters in presence of degenerate
ones.

For example we could have this situation:

instance i1: raft_id=1, target_state=Online, raft_configuration=voter
instance i2: raft_id=2, target_state=Expelled, raft_configuration=voter (!)
instance i3: raft_id=3, target_state=Offline, raft_configuration=voter (!)
instance i4: raft_id=4, target_state=Online, raft_configuration=learner (!)
instance i5: raft_id=5, target_state=Online, raft_configuration=learner (!)

BREAKING CHANGE: as soon as PostgreSQL protocol
is enabled by default, we must be careful with
`--pg-listen` cli flag when creating more than
a single instance, because we will suddenly get
a port confict error (busy port)

I found this by compiling tarantool with CMAKE_BUILD_TYPE=Debug

We used to automatically truncate the index in compact_log if the caller
requested to compact too many entries. This made it so that the
requirement of not compacting any un-applied entries was implicit in our
code base, which is not good as it allows for some bugs to creep in
(like the one we fix a couple commits ago).

Now this is changed and instead of silently adjusting the index of last
compacted entry, we just assert that it's no greater than the applied
index. As a consequence there's a minor improvement in do_raft_log_auto_compaction
function.

There was a hard-to-reproduce bug in our snapshot application code.
We always compact the raft log before applying the snapshot, because
the snapshot replaces the entries and some of the logic in raft-rs
seems to rely on this. The problem was, that our compact_log function
would not remove any unapplied entries, which makes sense for compaction
triggered automatically by raft log size, but doesn't make sense for
raft snapshot, as the snapshot contains the state corresponding to the
newer entries. The fix is simple: don't guard from unapplied entry
compaction in case the compaction is for raft snapshot.

We don't add any regression tests for this, because the implementation
would be too difficult and would need us to pollute the code with error
injection logic, which is not a worthy trade off in this case. But also
the logic will still be tested, because this bug was responsible for a
large amount of flaky tests, so we should see a significant reduction in
flakiness from now on in tests concerning raft snapshots.

TopologyCache is a collection of deserialized structures with
information about cluster topology. This currently includes data from
_pico_instance, _pico_replicaset, _pico_tier & _pico_service_route_table.
The info is automatically kept up to date with the corresponding system
tables. The TopologyCache also caches the immutable info related to the
current instance, like instance name, replicaset uuid, etc.

From now on we should be reading this data from TopologyCache whenever
possible instead of going directly to system tables as we were doing
previosly.

At the moment only the plugin RPC module has transitioned to using
TopologyCache but other modules should be refactored as well.
Especially governor.

Before this fix if requesting RPC by an invalid bucket_id we would send
an RPC to every replicaset to check if they have such a bucket_id.
This is not needed because we know the allowed range.

Now panics from plugin code are handled the same way panics from
picodata code, that is they log the backtrace to the tarantool logger
and then abort the process.

Introduce new parameters for alter system:
  - vdbe_max_steps
  - vtable_max_rows