This will result in new tables having at least 10 tablet replicas per
shard by default.
We want this to reduce tablet load imbalance due to differences in
tablet count per shard, where some shards have 1 tablet and some
shards have 2 tablets. With higher tablet count per shard, this
difference-by-one is less relevant.
Fixes#21967
In some tests, we explicity set the initial scale to 1 as some of the
existing tests assume 1 compaction group per shard.
test.py uses a lower default. Having many tablets per shard slows down
certain topology operations like decommission/replace/removenode,
where the running time is proportional to tablet count, not data size,
because constant cost (latency) of migration dominates. This latency
is due to group0 operations and barriers. This is especially
pronounced in debug mode. Scheduler allows at most 2 migrations per
shard, so this latency becomes a determining factor for decommission
speed.
To avoid this problem in tests, we use lower default for tablet count per
shard, 2 in debug/dev mode and 4 in release mode. Alternatively, we
could compensate by allowing more concurrency when migrating small
tablets, but there's no infrastructure for that yet.
I observed that with 10 tablets per shard, debug-mode
topology_custom.mv/test_mv_topology_change starts to time-out during
removenode (30 s).
We still have a number of issues to be solved for views with tablets.
Until they are fixed, we should prevent users from creating them,
and use the vnode-based views instead.
This patch prepares the feature for enabling views with tablets. The
feature is disabled by default, but currently it has no effect.
After all tests are adjusted to use the feature, we should depend
on the feature for deciding whether we can create materialized views
in tablet-enabled keyspaces.
The unit tests are adjusted to enable this feature explicitly, and it's
also added to the scylla sstable tool config - this tool treats all
tables as if they were tablet-based (surprisingly, with SimpleStrategy),
so for it to work on views, the new feature must be enabled.
Refs scylladb/scylladb#21832Closesscylladb/scylladb#21833
Increase pool size changes were recently reverted because of the flakiness for the test_gossip_boot test. Test started
to fail on adding the node to the cluster without any issues in the Scylla log file. In test logs it looked like the
installation process for the new node just hanged. After investigating the problem, I've found out that the issue is that
test.py was draining the io_executor pool for cleaning the directory during install that was set to eight workers. So
to fix the issue, io_executor pool should be increased to more or less the same ratio as it was: doubled cluster pool size.
Closesscylladb/scylladb#20276
... and replace it with boolean enable_tablets option. All the places
in the code are patched to check the latter option instead of the former
feature.
The option is OFF by default, but the default scylla.yaml file sets this
to true, so that newly installed clusters turn tablets ON.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Closesscylladb/scylladb#18898
We make the `consistent-topology-changes` experimental feature
unused and assumed to be true in 6.0. We remove code branches that
executed if `consistent-topology-changes` was disabled.
This reverts commit 11cafd2fc8, reversing
changes made to 2bae14f743.
Reverting because this series causes frequent CI failures, and the
proposed quickfix causes other failures of its own.
Fixes: #16113
This reverts commit 2860d43309, reversing
changes made to a3621dbd3e.
Reverting because rest_api.test_compaction_task started failing after
this was merged.
Fixes: #16005
Manage scylla servers for rest_api and cql-pytest suites
using PythonTestSuite. The pool size determines the max
number of servers test.py would run concurrently per
suite. For tiny suites (rest_api) the cost of starting
the servers overweights the cost of running tests so keep
it at a minimum. cql-pytest cas dozens of tests, so run them
in 4 parallel tracks.
