When forcing tablet count change via cql command, the underlying
tablet machinery takes some time to adjust. Original code waited
at most 0.1s for tablet data to be synchronized. This seems to be
not enough on debug builds, so we add exponential backoff and increase
maximum waiting time. Now the code will wait 0.1s first time and
continue waiting with each time doubling the time, up to maximum of 6 times -
or total time ~6s.
Fixes: SCYLLADB-1655
Closesscylladb/scylladb#29573
DynamoDB Streams API can only convey a single parent per stream shard.
Tablet merges produce 2 parents, which is incompatible. When streams
are requested on a tablet table, block tablet merges via
tablet_merge_blocked (the allocator suppresses new merge decisions and
revokes any active merge decision).
add_stream_options() sets tablet_merge_blocked=true alongside
enabled=true, so CreateTable needs no special handling — the flag
is inert on vnode tables and immediately effective on tablet tables.
For UpdateTable, CDC enablement is deferred: store the user's intent
via enable_requested, and let the topology coordinator finalize
enablement once no in-progress merges remain. A new helper,
defer_enabling_streams_block_tablet_merges(), amends the CDC options
to this deferred state.
Disabling streams clears all flags, immediately re-allowing merges.
The tablet allocator accesses the merge-blocked flag through a
schema::tablet_merges_forbidden() accessor rather than reaching into
CDC options directly.
Mark test_parent_children_merge as xfail and remove downward
(merge) steps from tablet_multipliers in test_parent_filtering and
test_get_records_with_alternating_tablets_count.
Add tests for Streams, when table uses tablets underneath.
One test verifies filtering using CHILD_SHARDS feature.
Other one makes sure we get read all data while the table
undergoes tablet count change.
Add `--tablet-load-stats-refresh-interval-in-seconds=1`
to `alternator/run` script, as otherwise newly added tests will fail.
The setting changes how often scylla refreshes tablet metadata.
This can't be done using `scylla_config_temporary`, as
1) default is 60 seconds
2) scylla will wait full timeout (60s) to read configuration variable again.
