org.apache.cassandra.utils.MergeIterator.Candidate - has Comparator field which is the same for all Candidates under an MergeIterator instance, we can move the field to MergeIterator level. Candidate is 4.8% of all allocations and we can save 20% (~1% of all allocations) of it for JDK 21 with compressed references on.
switch from ArrayList to array in org.apache.cassandra.db.rows.Row.Merger
The ArrayList iterator costs 0.72% and BulkIterator.Adapter costs 0.35%. So, in total we can save here ~1% of total allocations.
patch by Dmitry Konstantinov; reviewed by Francisco Guerrero for CASSANDRA-21359
Set 1 thread and 1 second for the measurement iteration (note: it is a smoke test only, we do not analyze results from such short measurements)
Exclude some options for heavy benchmarks by default
Shutdown all threads once JMH test is completed to avoid awaiting of a forked JVM till timeout at the end
patch by Dmitry Konstantinov; reviewed by Michael Semb Wever for CASSANDRA-21388
- now() functions must be deterministic (and derived from Accord timestamp)
- tombstone GC and TTL evaluation must be deterministic and based on both Accord timestamp and Accord GC mechanisms (that guarantee completeness of execution)
patch by Benedict; reviewed by Alex Petrov and Ariel Weisberg for CASSANDRA-21376
- consumer and producer threads wait signal without acquiring the lock first
- lock owners may prepare more work than they need, moving some dynamically-adjusted portion of the work from the prioritised lock-managed structures onto a non-blocking queue, so that other threads may consume work from there; the portion is continually micro-adjusted to target some available work whenever the lock is acquired.
- adopts/supports some features of the SEPExecutor:
- threads may auto-adjust the number of running threads based on how much time is collectively spent waiting, to minimise time spent signalling
- consumers may (timed-sleep) poll rather than await a signal, reducing the number of kernel interactions needed; relying on the auto-adjustment to bound the time the scheduler spends waking threads with no work to do
Also Fix:
- Client Result should not be persisted or included in Command object at any time
patch by Benedict; reviewed by Alex Petrov and Ariel Weisberg for CASSANDRA-21375
The following subcommands have been added:
* abortbootstrap Cancel and undo an inflight bootstrap
* abortmove Cancel and undo an inflight token move
* abortdecommission Cancel and undo an inflight decommission
* assassinate Remove a node from cluster metadata
* resetcms Redefine the CMS membership
* move Modify a node's (single) owned token
* describe Output a summary of the cluster metadata
* forcejoin Force a registered or joining node into a JOINED state
* print Output a full rendering of cluster metadata
* printdirectory Output a full rendering of the directory
* printdataplacements Output the full data placements
Patch by Venkata Harikrishna Nukala; reviewed by Alex Petrov and Sam Tunnicliffe
for CASSANDRA-19151
Dmitry Konstantinov