2463e524ed
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).
13 lines
277 B
YAML
13 lines
277 B
YAML
type: Python
|
|
pool_size: 10
|
|
|
|
skip_in_release:
|
|
- test_task_manager
|
|
- test_compaction_task
|
|
|
|
extra_scylla_cmdline_options:
|
|
- '--experimental-features=udf'
|
|
- '--enable-tablets=true'
|
|
- '--experimental-features=views-with-tablets'
|
|
- '--tablets-initial-scale-factor=1'
|