From bbcfd47bf5cb43db8a820ed9666f6765a8fc0fae Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Sun, 18 Aug 2024 18:40:37 +0300 Subject: [PATCH] doc: nodetool: toppartitions: document --samplers and --capacity In particular --capacity is critical for obtaining accurate measurements. Closes scylladb/scylladb#20192 --- .../operating-scylla/nodetool-commands/toppartitions.rst | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/docs/operating-scylla/nodetool-commands/toppartitions.rst b/docs/operating-scylla/nodetool-commands/toppartitions.rst index 083fc41e59..d440d48c7a 100644 --- a/docs/operating-scylla/nodetool-commands/toppartitions.rst +++ b/docs/operating-scylla/nodetool-commands/toppartitions.rst @@ -3,7 +3,7 @@ Nodetool toppartitions **toppartitions** - Samples cluster writes and reads and reports the most active partitions in a specified table and time frame. -**toppartitions** [<--ks-filters ks>] [<--cf-filters tables>] [<-d duration>] +**toppartitions** [<--ks-filters ks>] [<--cf-filters tables>] [<-d duration>] [<-s|--capacity capacity>] [<-a|--samplers samplers>] .. note:: @@ -29,6 +29,10 @@ ks-filters List of keyspaces cf-filters List of Tables (Column Families) ---------- ----------------------------------- duration The duration in milliseconds +---------- ----------------------------------- +capacity The capacity of the sampler; higher values increase accuracy at the cost of memory (default 256 keys). +---------- ----------------------------------- +samplers The samplers to use; ``WRITES``, ``READS``, or both (default). ========== =================================== For example: @@ -101,6 +105,9 @@ Write Latency The average read latency To know which node hold the partition key use the nodetool :doc:`getendpoints ` command. +If the margin of error column (+/-) approaches the Count column, the measurement is inaccurate. You can increase accuracy by specifying +the ``--capacity`` option. + For example: .. code-block:: shell