PostgreSQL Performance (read-only)
Resumen
Descripción del creador (original en inglés)
Read-only PostgreSQL performance diagnostics: slow queries, EXPLAIN, index advice, locks, functions
Los tres pilares de PopNx MCP
Estos tres nunca se combinan en una sola puntuación: las opiniones, las mediciones y la popularidad son cosas distintas.
- Opinión de usuariosiAún no hay reseñasLas reseñas se abrirán junto con las cuentas en una etapa posterior
- Nuestras revisiones básicasi1 de 1 superadasRevisado con información pública; el código aún no se ha escaneado
- UsoiMuy nuevo★ –
Qué puedes hacer con él
Todavía no escribimos un resumen sencillo para este. Abajo están los datos que leímos del registro.
- Conexión: Se ejecuta en tu computadora
- Transporte: Streamable HTTP
- Categoría: Bases de datos y conjuntos de datos
- Debes completar: PGPERF_DB_URL, PGPERF_DB_USER, PGPERF_DB_PASSWORD, MCP_API_KEY
Instalación
Elige la app de IA que usas y copia la configuración.
Antes de instalar
- Revisiones básicas: 1 de 1 superadas
- Se ejecuta en tu computadora con los permisos de tu usuario (archivos, red, apps).
- Debes completar tú:
PGPERF_DB_URL,PGPERF_DB_USER,PGPERF_DB_PASSWORD,MCP_API_KEY
Los valores marcados como secretos son llaves de tu cuenta. Nunca los compartas ni los pegues en un chat.
Necesitas
- DockerDocker instalado
¿Qué app usas?
Elige tu app arriba. La recordamos, así que la próxima vez el botón dirá “Instalar en …”.
Abre Claude Desktop → Settings → Developer → Edit Config y pega esto en claude_desktop_config.json
{
"mcpServers": {
"pg-perf": {
"command": "docker",
"args": [
"run",
"-i",
"--rm",
"-e",
"PGPERF_DB_URL",
"-e",
"PGPERF_DB_USER",
"-e",
"PGPERF_DB_PASSWORD",
"-e",
"MCP_API_KEY",
"ghcr.io/gouranshul/pg-perf-mcp:0.1.0"
],
"env": {
"PGPERF_DB_URL": "your-value",
"PGPERF_DB_USER": "your-value",
"PGPERF_DB_PASSWORD": "your-value",
"MCP_API_KEY": "your-value"
}
}
}
}Ejecuta esto en tu terminal
claude mcp add pg-perf --env PGPERF_DB_URL=your-value --env PGPERF_DB_USER=your-value --env PGPERF_DB_PASSWORD=your-value --env MCP_API_KEY=your-value -- docker run -i --rm -e PGPERF_DB_URL -e PGPERF_DB_USER -e PGPERF_DB_PASSWORD -e MCP_API_KEY ghcr.io/gouranshul/pg-perf-mcp:0.1.0Completa los valores vacíos antes de ejecutarlo.
O copia la configuración tú
Pégalo en .cursor/mcp.json de tu proyecto, o en ~/.cursor/mcp.json
{
"mcpServers": {
"pg-perf": {
"command": "docker",
"args": [
"run",
"-i",
"--rm",
"-e",
"PGPERF_DB_URL",
"-e",
"PGPERF_DB_USER",
"-e",
"PGPERF_DB_PASSWORD",
"-e",
"MCP_API_KEY",
"ghcr.io/gouranshul/pg-perf-mcp:0.1.0"
],
"env": {
"PGPERF_DB_URL": "your-value",
"PGPERF_DB_USER": "your-value",
"PGPERF_DB_PASSWORD": "your-value",
"MCP_API_KEY": "your-value"
}
}
}
}Tu navegador te pide permiso para abrir la app; luego la app muestra la configuración y te pide confirmar. Los valores de las claves quedan vacíos para que los completes tú.
O copia la configuración tú
Pégalo en .vscode/mcp.json de tu proyecto
{
"servers": {
"pg-perf": {
"type": "stdio",
"command": "docker",
"args": [
"run",
"-i",
"--rm",
"-e",
"PGPERF_DB_URL",
"-e",
"PGPERF_DB_USER",
"-e",
"PGPERF_DB_PASSWORD",
"-e",
"MCP_API_KEY",
"ghcr.io/gouranshul/pg-perf-mcp:0.1.0"
],
"env": {
"PGPERF_DB_URL": "your-value",
"PGPERF_DB_USER": "your-value",
"PGPERF_DB_PASSWORD": "your-value",
"MCP_API_KEY": "your-value"
}
}
}
}Tu navegador te pide permiso para abrir la app; luego la app muestra la configuración y te pide confirmar. Los valores de las claves quedan vacíos para que los completes tú.
Este se ejecuta en tu computadora, y ChatGPT solo puede conectarse a servidores en internet. Elige otra app.
Tu elección se guarda en una cookie en este dispositivo; no necesitas cuenta.
Valores que debes completar
- JDBC URL of the database to diagnose. From inside the container, use host.docker.internal for a database on your machine, e.g. jdbc:postgresql://host.docker.internal:5432/mydb
- A read-only role with pg_read_all_stats and pg_monitor (see docker/init.sql)
- Password of that role
- Bearer token clients must send, at least 16 characters (32+ random recommended)
Esta configuración se genera a partir de la ficha del creador en el registro. Si el README dice otra cosa, sigue el README.
Qué puede hacer
Se ejecuta en tu computadora; la lista de herramientas aparece en tu app de IA después de instalarlo.
Revisiones básicasi
Revisamos información que cualquiera puede ver; no hemos leído el código. Las revisiones que no aplican no se cuentan. · Revisado el 8 nov 2026
- ✓ Superada
El creador coincide con el repo
El nombre en el registro se verificó con la cuenta de GitHub gouranshul, dueña del repo
- … Aún sin revisar
Sigue en mantenimiento
Todavía no hemos leído este repo en GitHub
- … Aún sin revisar
Tiene licencia
Todavía no hemos leído este repo en GitHub
- – No aplica
El endpoint responde
Este se ejecuta en tu computadora; no hay endpoint en internet
- – No aplica
Inicio de sesión con OAuth
Se ejecuta en tu computadora y usa ajustes locales en su lugar
- … Aún sin revisar
Sin instrucciones ocultas en las descripciones de herramientas
Se ejecuta en tu computadora; solo podemos leer listas de herramientas de endpoints en internet
Comparado con otros en Bases de datos y conjuntos de datosi
- Más estrellas que el 0% de los otros 1144 servidores de esta categoría
- Publicado en el registro más recientemente que el 63% de los otros 1144 servidores de esta categoría
- Revisiones básicas iguales o mejores que el 100% de los otros 1144 servidores de esta categoría
Comparado con todos los servidores activos de esta categoría en el registro. Las estrellas solo cuentan cuando quien lo publica es dueño del repo.
Preguntas frecuentes
¿Es seguro PostgreSQL Performance (read-only)?
Superó 1 de 1 revisiones básicas aplicables. No hemos leído el código. Antes de agregar una clave o un token, revisa qué acceso pide el servidor y usa una clave que tenga solo los permisos que necesitas.
¿Qué claves o códigos necesita?
Debes completar: PGPERF_DB_URL, PGPERF_DB_USER, PGPERF_DB_PASSWORD, MCP_API_KEY
¿Se ejecuta en mi computadora o en la nube?
Se ejecuta en tu computadora. Tu app de IA lo inicia cuando hace falta, y los datos no pasan por los servidores del creador (a menos que el propio servidor llame a un servicio en línea).
¿Sigue en mantenimiento?
El repo de GitHub cambió por última vez –, y la última versión (0.1.0) llegó al registro hace 29 días.
¿Qué apps pueden usarlo?
Las apps compatibles con MCP, como Claude Desktop, Claude Code, Cursor y VS Code. También necesitas Docker en tu computadora.
¿Qué puedo usar en su lugar?
En la misma categoría: Supabase, MongoDB MCP Server, Elasticsearch MCP Server
Alternativas
Servidores de la misma categoría hechos por otros creadores, ordenados por estrellas.
Cómo leer una tarjeta:↓ Descargas por semanai★ Estrellas de GitHubiTres pilares: reseñas · revisiones · usoiActualizado = fecha en que se publicó la última versión en el registroi
README del creador
Abrir el README
Copiado tal cual del repo del creador. PopNx MCP no lo ha revisado ni lo respalda. Se quitaron HTML, imágenes y scripts. Los enlaces llevan fuera de este sitio.
pg-perf-mcp
An MCP server that lets AI assistants diagnose PostgreSQL performance problems safely: slow queries, EXPLAIN plans, index suggestions, table health and lock contention. It is read-only by design.
*A real Claude Code session against the demo shop, sped up. First it finds which database functions are slow and why. Then it explains a slow catalog query and estimates the fix with a hypothetical index. Asked to create the index, it says it can't: every tool is read-only.*
Why
When a page is slow, developers paste a query into a chat and ask "why is this slow?". The assistant then guesses, because it cannot see the plan, the table sizes, the existing indexes or which queries actually dominate the load.
pg-perf-mcp gives the assistant real numbers from `pg_stat_statements`, `EXPLAIN` and the catalogs, through a narrow, audited, read-only interface. It cannot change data, cannot run DDL, and never creates the indexes it recommends.
Demo
A condensed, illustrative session against the demo shop (docker compose up, then ./demo/workload.sh). Exact numbers vary from run to run:
You: The shop database feels slow. What's going on?
Claude: [top_slow_queries orderBy=total_time] The top statement by total time is SELECT id, status, total, created_at FROM shop.orders WHERE customer_id = $1 ORDER BY created_at DESC (thousands of calls, the largest share of total execution time).
[explain_query sql="... WHERE customer_id = 42 ORDER BY created_at DESC"] HIGH SEQ_SCAN_ON_LARGE_TABLE Seq Scan on shop.orders reads all ~1.0M rows of shop.orders to apply filter (customer_id = 42); only a handful match.
[suggest_indexes] CREATE INDEX CONCURRENTLY idx_orders_customer_id ON shop.orders (customer_id); hypopg: the planner would use it; estimated cost drops by well over 90%. Not executed. Review it and run it yourself, ideally off-peak.
[table_health table=shop.orders] Autovacuum is disabled on shop.orders and ~20% of rows are dead. Re-enable autovacuum and VACUUM.
Prioritized actions: 1) add the index above (orders.customer_id is a foreign key with no index),
- re-enable autovacuum on shop.orders, 3) ...
Architecture
flowchart LR
A["AI assistant (Claude Code, Claude Desktop, ...)"] -- "MCP over streamable HTTP Authorization: Bearer key" --> F["API key filter (constant-time)"] F --> M["MCP tools / resources / prompt Spring AI 2.0 annotations"] M --> R["ToolRunner audit log · metrics · safe errors"] R --> G["SqlGuard PG lexer + JSqlParser"] G --> E["ReadOnlyExecutor READ ONLY tx · always rollback statement/lock timeout · row cap"] R --> AN["analysis PlanAnalyzer · IndexAdvisor (pure functions)"] E --> P[("PostgreSQL 18 role mcp_readonly pg_stat_statements · hypopg")]
Tools
| Tool | What it does | Safety notes |
|---|---|---|
top_slow_queries | Most expensive statements from pg_stat_statements: normalized text, calls, total/mean/max ms, rows, cache hit ratio, share of total time. Order by total_time, mean_time, calls or rows. | Fixed SQL; sort column chosen from an enum. Excludes the server's own statements. |
explain_query | Summarized plan: 5 costliest nodes, seq scans on large tables, 10x row misestimates, disk sorts/hash spills, nested loops with many iterations. analyze=true adds real timings. $1 placeholders get a generic plan. | SQL guard first. ANALYZE runs in a read-only transaction that is rolled back and cancelled after the timeout. |
suggest_indexes | CREATE INDEX CONCURRENTLY candidates from filtered seq scans, join keys and ORDER BY ... LIMIT, each with a reason; validated with hypothetical indexes when hypopg is installed. | Never executed. Hypothetical indexes are reset in a savepoint so they cannot leak to other calls. |
unused_indexes | Indexes with idx_scan = 0, largest first, excluding primary key, unique and constraint indexes; includes size, definition and a DROP INDEX CONCURRENTLY to review. | Nothing is dropped. Reports when stats were last reset. |
table_health | Live/dead tuples, dead ratio, last (auto)vacuum/analyze, rows changed since analyze, seq vs index scans, sizes, with plain-language warnings. | Catalog reads only. |
blocking_sessions | Blocked/blocking pairs via pg_blocking_pids, truncated query texts, wait time, lock type/mode/table, blocker state, root blockers. | Never cancels or terminates anything. |
slow_functions | User-defined functions (PL/pgSQL, SQL, ...) ranked by total, self or mean time or calls, from pg_stat_user_functions, with language and volatility. | Catalog reads only. Needs track_functions. |
explain_function | Looks inside the functions a query calls: time per function, every statement executed inside them with calls, time and its own analyzed plan, and findings such as a seq scan inside a function, a function called once per row, or a read-only function left VOLATILE. Includes the function source. | SQL guard first; runs in the same rolled-back read-only transaction as explain_query, so functions that write fail. auto_explain is switched on for that transaction only, with generic plans so no data values appear. |
Resources: pg://schema/overview (tables, row estimates, sizes, indexes) and pg://schema/{table} (columns, indexes with scan counts, foreign keys flagged when unindexed). Prompt: diagnose_slow_database, a guided workflow: slow queries, then explain, suggest indexes, table health, functions, then a prioritized summary.
Why a separate tool for database functions
EXPLAIN shows a function call as one opaque expression, and charges its time to whichever plan node evaluates it. On the demo catalog page (20 products, each calling shop.product_rating), explain_query blames the index scan on products (184 ms self time) and finds nothing else serious. explain_function on the same query, against the full demo data:
shop.product_rating plpgsql 20 calls 99% of execution time
SELECT avg(rating) FROM shop.reviews WHERE product_id = p_product_id 20 calls 175 ms 96% of execution time HIGH FUNCTION_DOMINATES_QUERY shop.product_rating takes 99% of the query's execution time HIGH FUNCTION_CALLED_PER_ROW ran 20 times for one query (9.0 ms per call) HIGH SEQ_SCAN_ON_LARGE_TABLE inside shop.product_rating: Seq Scan on shop.reviews reads all ~250k rows to apply filter (reviews.product_id = $1)
How it works (ADR 0006): the query runs once with auto_explain enabled for that transaction only, so the plan of each nested statement comes back as a notice; per-function time comes from pg_stat_xact_user_functions and per-statement calls from pg_stat_statements, both as before/after differences.
Security model
Five independent layers stand between the assistant and a write (details in ADR 0001):
- SQL guard: exactly one plain
SELECT. It is checked by a PostgreSQL-faithful lexer *and* JSqlParser, and both must agree. Blocks DML/DDL, multiple statements, data-modifying CTEs,SELECT INTO,FOR UPDATE/SHARE,COPY,DO, and dangerous functions (pg_sleep*,*_file,lo_*,dblink*,set_config,pg_terminate_backend,query_to_xml, ...). It fails closed. - Read-only role:
mcp_readonlyhasSELECTpluspg_read_all_stats/pg_monitor, withdefault_transaction_read_only = onandstatement_timeout = 5sset on the role. - Read-only connections: Hikari
readOnly=trueand a read-only session default. - One rolled-back read-only transaction per call:
statement_timeout/lock_timeoutset locally,standard_conforming_stringsforced on, always rolled back. - Row cap: every result is capped (default 200 rows).
Around those layers: a bearer API key (constant-time comparison; only /actuator/health is open), a JSON audit line per call (SQL stored as a SHA-256 hash plus an 80-character preview), error messages with no stack traces or connection details, and metrics mcp.tool.duration and mcp.guard.rejections.
Quickstart
Requirements: Docker. There are two ways to start:
- [Use it on your database](#use-it-on-your-database): pull the published image. No clone or build.
- [Try the demo shop](#try-the-demo-shop): clone the repo and get a seeded database with realistic problems to diagnose.
Either way, finish with connecting your AI client.
Use it on your database
1. Pull the image (public on GHCR, built for amd64 and arm64):
docker pull ghcr.io/gouranshul/pg-perf-mcp:0.1.0
2. Prepare the database (once). Create a read-only role like mcp_readonly (see docker/init.sql) and make sure pg_stat_statements is in shared_preload_libraries. Prefer a replica or staging database: analyze=true and explain_function execute the query. For the function tools, also enable function tracking.
3. Run it. Put the settings in a file so secrets stay out of your shell history:
cat > pg-perf.env <<'EOF'
PGPERF_DB_URL=jdbc:postgresql://host.docker.internal:5432/mydb PGPERF_DB_USER=mcp_readonly PGPERF_DB_PASSWORD= MCP_API_KEY=<32+ random characters> EOF
docker run --rm --env-file pg-perf.env -p 127.0.0.1:8080:8080 ghcr.io/gouranshul/pg-perf-mcp:0.1.0
host.docker.internal reaches a database on your machine (Docker Desktop; on Linux add --add-host=host.docker.internal:host-gateway). The MCP endpoint is now http://localhost:8080/mcp.
4. Connect your AI client: see below.
Try the demo shop
To build and test from source you also need Java 25.
git clone https://github.com/gouranshul/pg-perf-mcp && cd pg-perf-mcp
cp .env.example .env # then replace the placeholder secrets docker compose up --build # Postgres 18 + seeded demo shop (~4.5M rows) + the MCP server on :8080
Generate some slow-query statistics (optional, but makes top_slow_queries interesting):
./demo/workload.sh # 60s of deliberately bad queries via pgbench
./demo/lock-scenario.sh # holds a row lock for 2 minutes so blocking_sessions has something to show ./demo/smoke-test.sh # curl-based end-to-end check of health, auth and two tool calls
Connect from Claude Code
claude mcp add --transport http pg-perf http://localhost:8080/mcp --header "Authorization: Bearer $MCP_API_KEY"
In PowerShell, set the key first, or the header goes out empty and the server answers 401:
$env:MCP_API_KEY = "<your MCP_API_KEY>"
claude mcp add --transport http pg-perf http://localhost:8080/mcp --header "Authorization: Bearer $env:MCP_API_KEY"
Or install it as a Claude Code plugin. Claude Code asks for the endpoint (default http://localhost:8080/mcp) and your MCP_API_KEY, which it keeps in secure storage:
/plugin install pg-perf --marketplace gouranshul/pg-perf-mcp
On Claude Code versions before 2.1.275, add the marketplace first: `/plu
Solo se muestra el principio; lee el resto en el repo