/**
* MySQL Resource - Health
*
* Comprehensive database health status including connection pool,
* thread activity, and InnoDB status.
*/
import type { MySQLAdapter } from "../MySQLAdapter.js";
import type {
ResourceDefinition,
RequestContext,
} from "../../../types/index.js";
export function createHealthResource(
adapter: MySQLAdapter,
): ResourceDefinition {
return {
uri: "mysql://health",
name: "Database Health",
title: "MySQL Database Health",
description: "Comprehensive database health status",
mimeType: "application/json",
annotations: {
audience: ["user", "assistant"],
priority: 1.0,
},
handler: async (_uri: string, _context: RequestContext) => {
// Execute health queries in parallel for better performance
const [statusResult, maxConnResult] = await Promise.all([
// Get uptime and connection info
adapter.executeQuery(`
SHOW GLOBAL STATUS WHERE Variable_name IN (
'Uptime', 'Threads_connected', 'Threads_running',
'Max_used_connections', 'Connections', 'Aborted_connects',
'Slow_queries', 'Questions', 'Com_select', 'Com_insert',
'Com_update', 'Com_delete', 'Innodb_buffer_pool_read_requests',
'Innodb_buffer_pool_reads', 'Table_locks_waited', 'Table_locks_immediate'
)
`),
// Get max_connections for percentage calculation
adapter.executeQuery("SHOW GLOBAL VARIABLES LIKE 'max_connections'"),
]);
const status: Record<string, string> = {};
for (const row of statusResult.rows ?? []) {
status[row["Variable_name"] as string] = row["Value"] as string;
}
const maxConnections = parseInt(
(maxConnResult.rows?.[0]?.["Value"] as string) ?? "151",
10,
);
// Calculate health metrics
const threadsConnected = parseInt(status["Threads_connected"] ?? "0", 10);
const connectionUsagePercent = Math.round(
(threadsConnected / maxConnections) * 100,
);
const bufferPoolRequests = parseInt(
status["Innodb_buffer_pool_read_requests"] ?? "0",
10,
);
const bufferPoolReads = parseInt(
status["Innodb_buffer_pool_reads"] ?? "0",
10,
);
const bufferPoolHitRatio =
bufferPoolRequests > 0
? Math.round(
((bufferPoolRequests - bufferPoolReads) / bufferPoolRequests) *
100 *
100,
) / 100
: 100;
const tableLockWaited = parseInt(status["Table_locks_waited"] ?? "0", 10);
const tableLockImmediate = parseInt(
status["Table_locks_immediate"] ?? "0",
10,
);
const tableLockContention =
tableLockWaited + tableLockImmediate > 0
? Math.round(
(tableLockWaited / (tableLockWaited + tableLockImmediate)) *
100 *
100,
) / 100
: 0;
// Get connection pool stats if available
const pool = adapter.getPool();
const poolStats = pool?.getStats();
return {
status: "healthy",
uptime_seconds: parseInt(status["Uptime"] ?? "0", 10),
connections: {
current: threadsConnected,
running: parseInt(status["Threads_running"] ?? "0", 10),
max_used: parseInt(status["Max_used_connections"] ?? "0", 10),
max_allowed: maxConnections,
usage_percent: connectionUsagePercent,
},
performance: {
questions: parseInt(status["Questions"] ?? "0", 10),
slow_queries: parseInt(status["Slow_queries"] ?? "0", 10),
buffer_pool_hit_ratio: bufferPoolHitRatio,
table_lock_contention_percent: tableLockContention,
},
queries: {
select: parseInt(status["Com_select"] ?? "0", 10),
insert: parseInt(status["Com_insert"] ?? "0", 10),
update: parseInt(status["Com_update"] ?? "0", 10),
delete: parseInt(status["Com_delete"] ?? "0", 10),
},
pool: poolStats ?? null,
};
},
};
}
