import { executeQuery } from '../db/index.js';
import { waitStatsSchema } from '../validators/schemas.js';
import { formatSuccess, formatError } from '../utils/formatters.js';
import type { ToolResponse } from '../types.js';
/**
* Tool: monitor_wait_stats
* Monitor wait statistics
*/
export async function monitorWaitStats(args: unknown): Promise<ToolResponse> {
try {
const { top, excludeIdle } = waitStatsSchema.parse(args);
const idleWaits = [
'ClientRead',
'ClientWrite',
'ClientWait',
'Idle',
'Activity',
'Idle in transaction',
];
let query = `
SELECT
wait_event AS "waitType",
COUNT(*) AS "waitingTasksCount",
EXTRACT(EPOCH FROM MAX(now() - query_start)) * 1000 AS "totalWaitTimeMs",
EXTRACT(EPOCH FROM MAX(now() - query_start)) * 1000 AS "maxWaitTimeMs",
NULL::numeric AS "signalWaitTimeMs",
EXTRACT(EPOCH FROM MAX(now() - query_start)) * 1000 AS "resourceWaitTimeMs",
CASE WHEN SUM(EXTRACT(EPOCH FROM (now() - query_start)) * 1000) OVER() = 0 THEN 0
ELSE ROUND(
100.0 * (EXTRACT(EPOCH FROM MAX(now() - query_start)) * 1000)
/ SUM(EXTRACT(EPOCH FROM (now() - query_start)) * 1000) OVER(),
2
)
END AS "percentTotal"
FROM pg_stat_activity
WHERE wait_event IS NOT NULL
`;
if (excludeIdle) {
query += ` AND wait_event NOT IN ('${idleWaits.join("','")}')`;
}
query += `
GROUP BY wait_event
ORDER BY totalWaitTimeMs DESC
LIMIT @top
`;
const result = await executeQuery(query, { top }, top);
return formatSuccess({
waitStats: result.rows,
count: result.rowCount,
excludedIdleWaits: excludeIdle,
});
} catch (error) {
return formatError(error);
}
}
/**
* Tool definition for monitor_wait_stats
*/
export const monitorWaitStatsDefinition = {
name: 'monitor_wait_stats',
description:
'Monitor wait statistics to identify performance bottlenecks. Shows wait types, counts, and times.',
inputSchema: {
type: 'object' as const,
properties: {
top: {
type: 'number',
default: 10,
minimum: 1,
maximum: 100,
description: 'Number of wait types to return (default: 10)',
},
excludeIdle: {
type: 'boolean',
default: true,
description: 'Exclude idle/benign waits (default: true)',
},
},
},
};
