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feat(webapp): per-client database pool metrics that survive the driver adapter #4541

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c71c46b
feat(webapp): per-client database pool metrics that survive the drive…
ericallam Aug 8, 2026
5d964b2
feat(webapp): use canonical datasource labels for db_client metric at…
ericallam Aug 8, 2026
0a93dc0
fix(webapp): address review on db pool metrics registry
ericallam Aug 9, 2026
2ec585b
fix(webapp): oxfmt the metrics module and simplify the server-changes…
ericallam Aug 9, 2026
a9b9ccd
fix(webapp): don't emit zeroed engine metrics when $metrics read fails
ericallam Aug 10, 2026
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6 changes: 6 additions & 0 deletions .server-changes/db-pool-metrics-per-client.md
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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,6 @@
---
area: webapp
type: improvement
---

Database connection metrics are now reported for every configured database connection instead of only the primary one, and stay accurate regardless of connection type.
162 changes: 120 additions & 42 deletions apps/webapp/app/db.server.ts
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Original file line numberDiff line numberDiff line change
Expand Up@@ -24,6 +24,7 @@ import {
logTransactionInfrastructureError,
} from "./utils/prismaErrors";
import { singleton } from "./utils/singleton";
import { registerDatabaseMetricsSource } from "./utils/databaseMetrics.server";
import {
isSplitEnabled,
assertSplitRealtimeInterlock,
Expand DownExpand Up@@ -247,16 +248,16 @@ export function selectRunOpsTopology(
if (config.legacySharesControlPlane) {
legacyRunOps = controlPlane;
} else {
const legacyWriter = builders.buildLegacyWriter(config.legacyUrl, "run-ops-legacy-writer");
const legacyWriter = builders.buildLegacyWriter(config.legacyUrl, "legacy-run-ops-writer");
const legacyReplica: PrismaReplicaClient = config.legacyReplicaUrl
? builders.buildLegacyReplica(config.legacyReplicaUrl, "run-ops-legacy-reader")
? builders.buildLegacyReplica(config.legacyReplicaUrl, "legacy-run-ops-replica")
: legacyWriter;
legacyRunOps = { writer: legacyWriter, replica: legacyReplica };
}

const newWriter = builders.buildNewWriter(config.newUrl, "run-ops-new-writer");
const newWriter = builders.buildNewWriter(config.newUrl, "run-ops-writer");
const newReplica: RunOpsPrismaClient = config.newReplicaUrl
? builders.buildNewReplica(config.newReplicaUrl, "run-ops-new-reader")
? builders.buildNewReplica(config.newReplicaUrl, "run-ops-replica")
: newWriter;

return {
Expand DownExpand Up@@ -430,19 +431,25 @@ function getClient() {

return buildWriterClient({
url,
clientType: "writer",
clientType: "control-plane-writer",
poolTimeout: env.DATABASE_WRITER_POOL_TIMEOUT,
connectTimeout: env.DATABASE_WRITER_CONNECTION_TIMEOUT,
useDriverAdapter: env.CONTROL_PLANE_DATABASE_WRITER_DRIVER_ADAPTER === "1",
});
}

type DriverAdapterPool = {
adapter: PrismaPg;
pool: Pool;
poolCounters: { opened: () => number; closed: () => number };
};

function buildDriverAdapterPool(
connectionString: string,
clientType: string,
poolTimeoutSeconds: number,
connectionLimit: number
): PrismaPg {
): DriverAdapterPool {
const pool = new Pool({
connectionString,
max: connectionLimit,
Expand All@@ -457,14 +464,27 @@ function buildDriverAdapterPool(
});
});

let opened = 0;
let closed = 0;
pool.on("connect", () => {
opened += 1;
});
pool.on("remove", () => {
closed += 1;
});

let schema: string | undefined;
try {
schema = new URL(connectionString).searchParams.get("schema") ?? undefined;
} catch {
schema = undefined;
}

return new PrismaPg(pool, { schema, disposeExternalPool: true });
return {
adapter: new PrismaPg(pool, { schema, disposeExternalPool: true }),
pool,
poolCounters: { opened: () => opened, closed: () => closed },
};
}

// Generalized writer builder shared by the control-plane client and the run-ops
Expand DownExpand Up@@ -548,21 +568,34 @@ export function buildWriterClient({
: []) satisfies Prisma.LogDefinition[]),
] satisfies Prisma.LogDefinition[];

const client = useDriverAdapter
? new PrismaClient({
adapter: buildDriverAdapterPool(
url,
clientType,
poolTimeout ?? env.DATABASE_POOL_TIMEOUT,
env.DATABASE_CONNECTION_LIMIT
),
log: logConfig,
})
const driverPool = useDriverAdapter
? buildDriverAdapterPool(
url,
clientType,
poolTimeout ?? env.DATABASE_POOL_TIMEOUT,
env.DATABASE_CONNECTION_LIMIT
)
: undefined;

const client = driverPool
? new PrismaClient({ adapter: driverPool.adapter, log: logConfig })
: new PrismaClient({
datasources: { db: { url: databaseUrl.href } },
log: logConfig,
});

registerDatabaseMetricsSource(
driverPool
? {
clientType,
usesDriverAdapter: true,
client,
pool: driverPool.pool,
poolCounters: driverPool.poolCounters,
}
: { clientType, usesDriverAdapter: false, client }
);

// Only use structured logging if we're not already logging to stdout
if (process.env.PRISMA_LOG_TO_STDOUT !== "1") {
client.$on("info", (log) => {
Expand DownExpand Up@@ -631,7 +664,7 @@ function getReplicaClient() {

return buildReplicaClient({
url,
clientType: "reader",
clientType: "control-plane-replica",
poolTimeout: env.DATABASE_READ_REPLICA_POOL_TIMEOUT,
connectTimeout: env.DATABASE_READ_REPLICA_CONNECTION_TIMEOUT,
useDriverAdapter: env.CONTROL_PLANE_DATABASE_REPLICA_DRIVER_ADAPTER === "1",
Expand DownExpand Up@@ -719,21 +752,34 @@ export function buildReplicaClient({
: []) satisfies Prisma.LogDefinition[]),
] satisfies Prisma.LogDefinition[];

const replicaClient = useDriverAdapter
? new PrismaClient({
adapter: buildDriverAdapterPool(
url,
clientType,
poolTimeout ?? env.DATABASE_POOL_TIMEOUT,
env.DATABASE_CONNECTION_LIMIT
),
log: logConfig,
})
const driverPool = useDriverAdapter
? buildDriverAdapterPool(
url,
clientType,
poolTimeout ?? env.DATABASE_POOL_TIMEOUT,
env.DATABASE_CONNECTION_LIMIT
)
: undefined;

const replicaClient = driverPool
? new PrismaClient({ adapter: driverPool.adapter, log: logConfig })
: new PrismaClient({
datasources: { db: { url: replicaUrl.href } },
log: logConfig,
});

registerDatabaseMetricsSource(
driverPool
? {
clientType,
usesDriverAdapter: true,
client: replicaClient,
pool: driverPool.pool,
poolCounters: driverPool.poolCounters,
}
: { clientType, usesDriverAdapter: false, client: replicaClient }
);

// Only use structured logging if we're not already logging to stdout
if (process.env.PRISMA_LOG_TO_STDOUT !== "1") {
replicaClient.$on("info", (log) => {
Expand DownExpand Up@@ -813,14 +859,18 @@ function buildRunOpsWriterClient({
}`
);

const client = useDriverAdapter
const driverPool = useDriverAdapter
? buildDriverAdapterPool(
url,
clientType,
env.RUN_OPS_DATABASE_WRITER_POOL_TIMEOUT ?? env.DATABASE_POOL_TIMEOUT,
env.DATABASE_CONNECTION_LIMIT
)
: undefined;

const client = driverPool
? new RunOpsPrismaClient({
adapter: buildDriverAdapterPool(
url,
clientType,
env.RUN_OPS_DATABASE_WRITER_POOL_TIMEOUT ?? env.DATABASE_POOL_TIMEOUT,
env.DATABASE_CONNECTION_LIMIT
),
adapter: driverPool.adapter,
log: [
{ emit: "event", level: "error" },
{ emit: "event", level: "info" },
Expand All@@ -844,6 +894,18 @@ function buildRunOpsWriterClient({
],
});

registerDatabaseMetricsSource(
driverPool
? {
clientType,
usesDriverAdapter: true,
client,
pool: driverPool.pool,
poolCounters: driverPool.poolCounters,
}
: { clientType, usesDriverAdapter: false, client }
);

if (process.env.PRISMA_LOG_TO_STDOUT !== "1") {
client.$on("info", (log) => logger.info("RunOpsPrismaClient info", { clientType, event: log }));
client.$on("warn", (log) => logger.warn("RunOpsPrismaClient warn", { clientType, event: log }));
Expand DownExpand Up@@ -894,14 +956,18 @@ function buildRunOpsReplicaClient({
}`
);

const client = useDriverAdapter
const driverPool = useDriverAdapter
? buildDriverAdapterPool(
url,
clientType,
env.RUN_OPS_DATABASE_READ_REPLICA_POOL_TIMEOUT ?? env.DATABASE_POOL_TIMEOUT,
env.RUN_OPS_DATABASE_READ_REPLICA_CONNECTION_LIMIT ?? env.DATABASE_CONNECTION_LIMIT
)
: undefined;

const client = driverPool
? new RunOpsPrismaClient({
adapter: buildDriverAdapterPool(
url,
clientType,
env.RUN_OPS_DATABASE_READ_REPLICA_POOL_TIMEOUT ?? env.DATABASE_POOL_TIMEOUT,
env.RUN_OPS_DATABASE_READ_REPLICA_CONNECTION_LIMIT ?? env.DATABASE_CONNECTION_LIMIT
),
adapter: driverPool.adapter,
log: [
{ emit: "event", level: "error" },
{ emit: "event", level: "info" },
Expand All@@ -925,6 +991,18 @@ function buildRunOpsReplicaClient({
],
});

registerDatabaseMetricsSource(
driverPool
? {
clientType,
usesDriverAdapter: true,
client,
pool: driverPool.pool,
poolCounters: driverPool.poolCounters,
}
: { clientType, usesDriverAdapter: false, client }
);

if (process.env.PRISMA_LOG_TO_STDOUT !== "1") {
client.$on("info", (log) => logger.info("RunOpsPrismaClient info", { clientType, event: log }));
client.$on("warn", (log) => logger.warn("RunOpsPrismaClient warn", { clientType, event: log }));
Expand Down
13 changes: 1 addition & 12 deletions apps/webapp/app/routes/metrics.ts
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Original file line numberDiff line numberDiff line change
@@ -1,5 +1,4 @@
import type { LoaderFunctionArgs } from "@remix-run/server-runtime";
import { prisma } from "~/db.server";
import { metricsRegister } from "~/metrics.server";

export async function loader({ request }: LoaderFunctionArgs) {
Expand All@@ -13,17 +12,7 @@ export async function loader({ request }: LoaderFunctionArgs) {
}
}

// We need to remove empty lines from the prisma metrics, grafana doesn't like them
let prismaMetrics = "";
try {
prismaMetrics = (await prisma.$metrics.prometheus()).replace(/^\s*[\r\n]/gm, "");
} catch {
prismaMetrics = "";
}
const coreMetrics = await metricsRegister.metrics();

// Order matters, core metrics end with `# EOF`, prisma metrics don't
const metrics = prismaMetrics + coreMetrics;
const metrics = await metricsRegister.metrics();
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return new Response(metrics, {
headers: {
Expand Down
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