From dc2eb8aacbefbeff2d9f02957156b103c5cdcada Mon Sep 17 00:00:00 2001
From: Sergey Tatarintsev <tatarintsev@prisma.io>
Date: Mon, 6 Nov 2023 10:15:42 +0100
Subject: [PATCH] fix(driver-adapters): Ensure transaction metrics do not get
 negative

Current dispatcher for a thread gets lost somewhere within napi-rs/napi
`ThreadsafeFunction` nad thearfore, gauge increment in `Transaction::new` is not registered. That in turn means that when the same gauge is decremented in `commit`/`rollback`, it's value will get negative.

Moving increment to proxy fixes the problem.

Unblocks prisma/prisma-orm#21746
---
 query-engine/driver-adapters/src/proxy.rs       | 7 +++++++
 query-engine/driver-adapters/src/transaction.rs | 4 ++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/query-engine/driver-adapters/src/proxy.rs b/query-engine/driver-adapters/src/proxy.rs
index da03336bdf53..62086a245199 100644
--- a/query-engine/driver-adapters/src/proxy.rs
+++ b/query-engine/driver-adapters/src/proxy.rs
@@ -4,6 +4,7 @@ use std::str::FromStr;
 use crate::async_js_function::AsyncJsFunction;
 use crate::conversion::JSArg;
 use crate::transaction::JsTransaction;
+use metrics::increment_gauge;
 use napi::bindgen_prelude::{FromNapiValue, ToNapiValue};
 use napi::threadsafe_function::{ErrorStrategy, ThreadsafeFunction};
 use napi::{JsObject, JsString};
@@ -555,6 +556,12 @@ impl DriverProxy {
 
     pub async fn start_transaction(&self) -> quaint::Result<Box<JsTransaction>> {
         let tx = self.start_transaction.call(()).await?;
+
+        // Decrement for this gauge is done in JsTransaction::commit/JsTransaction::rollback
+        // Previously, it was done in JsTransaction::new, similar to the native Transaction.
+        // However, correct Dispatcher is lost there and increment does not register, so we moved
+        // it here instead.
+        increment_gauge!("prisma_client_queries_active", 1.0);
         Ok(Box::new(tx))
     }
 }
diff --git a/query-engine/driver-adapters/src/transaction.rs b/query-engine/driver-adapters/src/transaction.rs
index 0d26c7f863aa..6c75ff4ad6b1 100644
--- a/query-engine/driver-adapters/src/transaction.rs
+++ b/query-engine/driver-adapters/src/transaction.rs
@@ -22,8 +22,6 @@ pub(crate) struct JsTransaction {
 
 impl JsTransaction {
     pub(crate) fn new(inner: JsBaseQueryable, tx_proxy: TransactionProxy) -> Self {
-        increment_gauge!("prisma_client_queries_active", 1.0);
-
         Self { inner, tx_proxy }
     }
 
@@ -40,6 +38,7 @@ impl JsTransaction {
 #[async_trait]
 impl QuaintTransaction for JsTransaction {
     async fn commit(&self) -> quaint::Result<()> {
+        // increment of this gauge is done in DriverProxy::startTransaction
         decrement_gauge!("prisma_client_queries_active", 1.0);
 
         let commit_stmt = "COMMIT";
@@ -55,6 +54,7 @@ impl QuaintTransaction for JsTransaction {
     }
 
     async fn rollback(&self) -> quaint::Result<()> {
+        // increment of this gauge is done in DriverProxy::startTransaction
         decrement_gauge!("prisma_client_queries_active", 1.0);
 
         let rollback_stmt = "ROLLBACK";