Add a visual indication for groups of co-located tablets in
tablet-mon.py.
We order the tablets by groups, and draw a rectangle that connects
tablets that are co-located
For co-located tablets we need to read the tablet information from the
tablet map referenced by base_table.
Fix tablet-mon.py to handle co-located tablets by checking if base_table
is set when reading the tablets of a table, and if so refer to the base
table map.
After load-balancer was made capacity-aware it no longer equalizes tablet count per shard, but rather utilization of shard's storage. This makes the old presentation mode not useful in assessing whether balance was reached, since nodes with less capacity will get fewer tablets when in balanced state. This PR adds a new default presentation mode which scales tablet size by its storage utilization so that tablets which have equal shard utilization take equal space on the graph.
To facilitate that, a new virtual table was added: system.load_per_node, which allows the tool to learn about load balancer's view on per-node capacity. It can also serve as a debugging interface to get a view of current balance according to the load-balancer.
Closesscylladb/scylladb#23584
* github.com:scylladb/scylladb:
tablet-mon.py: Add presentation mode which scales tablet size by its storage utilization
tablet-mon.py: Center tablet id text properly in the vertical axis
tablet-mon.py: Show migration stage tag in table mode only when migrating
virtual-tables: Introduce system.load_per_node
virtual_tables: memtable_filling_virtual_table: Propagate permit to execute()
docs: virtual-tables: Fix instructions
service: tablets: Keep load_stats inside tablet_allocator
Per-node capacity is queried from system.load_per_node
Tablet height in each node is scaled so that equal height = equal node
utilization.
The nominal height is assigned to the node which has the smallest
capacity, so nodes with higher capacity will have smaller tablets than
normal.
Currently, in the streaming stage of rebuild tablet transition,
we stream tablet data from all replicas.
This patch series splits the streaming stage into two phases:
- repair phase, where we repair the tablet;
- streaming phase, where we stream tablet data from one replica.
rebuild_repair is a stage that will be used to perform the repair
phase. It executes the tablet repair on tablet_info::replicas.
A primary replica out of migration_streraming_info::read_from is
the repair master. If the repair succeeds, we move to streaming
tablet transition stage, and to cleanup_target - if it fails.
The repair bypasses the tablet repair scheduler and it does not update
the repair_time.
A transition to the rebuild_repair stage will be added in the following
patches.
Tablet sequeunce number was part of the tablet identifier together
with last token, so on split and merge all ids changed and it appeared
in the simulator as all tablets of a table dropping and being created
anew. That's confusing. After this change, only last token is part of
the id, so split appears as adding tablets and merge appears as
removing half the tablets, which is more accurate.
That will help visualizing co-location of sibling tablets for a table
that is undergoing merge.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
