Tidb Cluster Inspector

-- All nodes: type, address, version, status, uptime
SELECT
  TYPE AS role, INSTANCE AS address,
  VERSION AS version, STATUS AS status,
  START_TIME AS start_time
FROM information_schema.cluster_info
ORDER BY TYPE, INSTANCE;

-- Per-node server info
SELECT
  TYPE, INSTANCE, VERSION,
  TIMESTAMPDIFF(HOUR, START_TIME, NOW()) AS uptime_hours
FROM information_schema.cluster_info
WHERE STATUS != 'Up' OR STATUS IS NULL;

-- TiDB v4.0+: slow query from system table
SELECT
  Txn_start, Query_time, Parse_time, Compile_time,
  Process_time, Wait_time, Backoff_time,
  Request_count, Coprocessor_involved_count,
  LEFT(Query, 300) AS sql_fragment
FROM information_schema.slow_query
WHERE Time > DATE_SUB(NOW(), INTERVAL 1 HOUR)
ORDER BY Query_time DESC
LIMIT 20;

-- TiDB v6.0+: cluster-wide slow query
SELECT * FROM information_schema.cluster_slow_query
WHERE Time > DATE_SUB(NOW(), INTERVAL 1 HOUR)
ORDER BY Query_time DESC LIMIT 20;

-- Current hot regions: which tables/indexes are hot, read vs write, and how hot.
-- Columns verified against TiDB information_schema.TIDB_HOT_REGIONS (v4.0+).
SELECT
  DB_NAME,
  TABLE_NAME,
  INDEX_NAME,
  TYPE AS hot_type,             -- 'read' or 'write'
  MAX_HOT_DEGREE AS hot_degree, -- >0 means hot; higher = hotter
  FLOW_BYTES,                   -- bytes read + written in the region
  REGION_COUNT
FROM information_schema.TIDB_HOT_REGIONS
ORDER BY MAX_HOT_DEGREE DESC, FLOW_BYTES DESC
LIMIT 20;

-- Per-store storage and region distribution
SELECT
  STORE_ID,
  ADDRESS,
  STORE_STATE_NAME AS state,
  CAPACITY,
  AVAILABLE,
  USED_SIZE,
  ROUND(USED_SIZE / CAPACITY * 100, 2) AS usage_pct,
  REGION_COUNT,
  LEADER_COUNT
FROM information_schema.tikv_store_status
ORDER BY STORE_ID;

-- Check PD scheduling configuration
SHOW CONFIG WHERE TYPE = 'pd' AND NAME LIKE '%schedule%';
SHOW CONFIG WHERE TYPE = 'pd' AND NAME LIKE '%replicate%';

-- Leader concentration per TiKV store (cluster-level, lightweight — no full
-- region scan). leader_share_pct should be roughly even across TiKV nodes.
SELECT
  STORE_ID,
  ADDRESS,
  REGION_COUNT,
  LEADER_COUNT,
  ROUND(LEADER_COUNT / NULLIF(REGION_COUNT, 0) * 100, 2) AS leader_pct_of_store,
  ROUND(
    LEADER_COUNT /
      (SELECT SUM(LEADER_COUNT) FROM information_schema.TIKV_STORE_STATUS) * 100,
    2
  ) AS leader_share_pct
FROM information_schema.TIKV_STORE_STATUS
ORDER BY leader_share_pct DESC;

SELECT
  DIGEST_TEXT,
  SCHEMA_NAME,
  STMT_TYPE,
  EXEC_COUNT,
  ROUND(SUM_LATENCY / 1e9, 3) AS total_latency_s,
  ROUND(AVG_LATENCY / 1e6, 2) AS avg_latency_ms,
  ROUND(MAX_LATENCY / 1e6, 2) AS max_latency_ms
FROM information_schema.CLUSTER_STATEMENTS_SUMMARY
WHERE EXEC_COUNT > 0
ORDER BY SUM_LATENCY DESC
LIMIT 10;

SELECT
  DIGEST_TEXT,
  SCHEMA_NAME,
  EXEC_COUNT,
  ROUND(AVG_LATENCY / 1e6, 2) AS avg_latency_ms
FROM information_schema.CLUSTER_STATEMENTS_SUMMARY
WHERE EXEC_COUNT > 0
ORDER BY EXEC_COUNT DESC
LIMIT 10;

SELECT
  DIGEST_TEXT,
  SCHEMA_NAME,
  EXEC_COUNT,
  SUM_MEMORY,
  ROUND(AVG_MEM / 1024 / 1024, 2) AS avg_mem_mb
FROM information_schema.CLUSTER_STATEMENTS_SUMMARY
WHERE EXEC_COUNT > 0
ORDER BY SUM_MEMORY DESC
LIMIT 10;

SELECT
  DIGEST_TEXT,
  SCHEMA_NAME,
  STMT_TYPE,
  EXEC_COUNT,
  ROUND(SUM_LATENCY / 1e9, 3) AS total_latency_s,
  ROUND(AVG_LATENCY / 1e6, 2) AS avg_latency_ms,
  ROUND(SUM_MEMORY / 1024 / 1024, 2) AS total_mem_mb
FROM information_schema.CLUSTER_STATEMENTS_SUMMARY
WHERE EXEC_COUNT > 0
ORDER BY SUM_LATENCY DESC
LIMIT 5;

SELECT @@tidb_enable_stmt_summary AS enabled;   -- expected ON (default since v4.0)
-- SET GLOBAL tidb_enable_stmt_summary = ON;     -- requires SUPER privilege; recommend to DBA