Merge latency snapshot

Record phase-level cumulative percentile latency statistics for index merges over time.

All statistics reset upon node restart.

This table is configured with gc_grace_seconds 0 to avoid issues with persistent tombstones as rows expire; tombstones are removed during compaction no matter how recently they were created.

JMX analog

com.datastax.bdp/search/core/MergeMetrics

Schema

CREATE TABLE dse_perf.solr_merge_latency_snapshot (
  node_ip inet,
  core text,
  date timestamp,
  time timestamp,
  phase text,
  count bigint,
  latency_percentiles_micros maptext, bigint
  PRIMARY KEY ((node_ip, core, date), phase, time)
)
WITH CLUSTERING ORDER BY (phase ASC, time DESC)
AND gc_grace_seconds=0
Field purpose
Field Type Purpose

node_ip

inet

Node IP address.

core

text

Search index name, such as keyspace_name.table_name.

date

timestamp

Midnight on the mm/dd/yyyy the snapshot was recorded.

time

timestamp

Time the snapshot was recorded.

phase

text

INIT, WARM, EXECUTE

count

bigint

Cumulative number of queries recorded.

latency_percentiles_micros

maptext, bigint

Cumulative latency percentiles of query: 25%, 50%, 75%, 95%, 99% and 99.9%.

Snapshots recorded on 10/17/2014 for core keyspace.table on the node 127.0.0.1:

SELECT *
FROM solr_merge_latency_snapshot
WHERE node_ip = '127.0.0.1' AND core = 'keyspace.table' AND date = '2014-10-17';

Most recent 5 snapshots for the EXECUTE phase recorded on 10/17/2014 for core keyspace.table on the node 127.0.0.1:

SELECT *
FROM solr_merge_latency_snapshot
WHERE node_ip = '127.0.0.1'
    AND core = 'keyspace.table'
    AND date = '2014-10-17'
    AND phase = 'EXECUTE'
LIMIT 5;

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