GreptimeDB MCP Server

# Table Diagnostics: {{ table }} Analyze table structure, region health, storage, and query performance. ## Available Tools - `describe_table` - Get table schema - `explain_query` - Analyze query execution plan (set `analyze=true` for runtime stats) - `execute_sql` - Run diagnostic SQL queries ## Schema Analysis ```sql -- Table structure DESCRIBE {{ table }}; -- Full DDL SHOW CREATE TABLE {{ table }}; -- Column details SELECT column_name, data_type, semantic_type, is_nullable FROM INFORMATION_SCHEMA.COLUMNS WHERE table_name = '{{ table }}'; ``` ## Region Health ```sql -- Region distribution and status SELECT region_id, peer_id, is_leader, status FROM INFORMATION_SCHEMA.REGION_PEERS WHERE table_name = '{{ table }}'; -- Region statistics (rows, disk usage) SELECT r.region_id, r.disk_size, r.memtable_size, r.region_rows FROM INFORMATION_SCHEMA.REGION_STATISTICS r JOIN INFORMATION_SCHEMA.TABLES t ON r.table_id = t.table_id WHERE t.table_name = '{{ table }}'; -- Find unhealthy regions (status should be ALIVE) SELECT region_id, peer_id, status, down_seconds FROM INFORMATION_SCHEMA.REGION_PEERS WHERE table_name = '{{ table }}' AND status != 'ALIVE'; ``` ## Storage Analysis ```sql -- SST file details for the table SELECT s.file_id, s.file_size, s.num_rows, s.min_ts, s.max_ts, s.level FROM INFORMATION_SCHEMA.SSTS_MANIFEST s JOIN INFORMATION_SCHEMA.TABLES t ON s.table_id = t.table_id WHERE t.table_name = '{{ table }}'; -- Index information for the table SELECT i.index_file_path, i.index_type, i.index_file_size, i.target_json FROM INFORMATION_SCHEMA.SSTS_INDEX_META i JOIN INFORMATION_SCHEMA.TABLES t ON i.table_id = t.table_id WHERE t.table_name = '{{ table }}'; ``` ## Query Optimization Use `explain_query` tool for query analysis: ``` # Basic execution plan explain_query(query="SELECT * FROM {{ table }} WHERE ts > now() - INTERVAL '1 hour'") # With runtime stats (actual execution) explain_query(query="SELECT * FROM {{ table }} LIMIT 100", analyze=true) ``` **What to look for:** - Full table scans vs index usage - Partition pruning effectiveness - Join strategies and row estimates ## Cluster Overview ```sql -- Node topology SELECT peer_id, peer_type, peer_addr, version, uptime, node_status FROM INFORMATION_SCHEMA.CLUSTER_INFO; -- Running queries SELECT id, query, start_timestamp, elapsed_time FROM INFORMATION_SCHEMA.PROCESSLIST; ``` ## References - [INFORMATION_SCHEMA](https://docs.greptime.com/reference/sql/information-schema/overview) - System tables overview - [CLUSTER_INFO](https://docs.greptime.com/reference/sql/information-schema/cluster-info) - Node topology and status - [REGION_PEERS](https://docs.greptime.com/reference/sql/information-schema/region-peers) - Region distribution and health - [REGION_STATISTICS](https://docs.greptime.com/reference/sql/information-schema/region-statistics) - Region disk and memory usage - [EXPLAIN Query](https://docs.greptime.com/reference/sql/explain) - Query execution plan analysis - [SHOW Statements](https://docs.greptime.com/reference/sql/show) - SHOW CREATE TABLE and other statements