From 01fadd93d78ba37a57d2d09e01f0bce7f8d5869c Mon Sep 17 00:00:00 2001
From: Barry Hagan <barryhagan@users.noreply.github.com>
Date: Thu, 10 Jul 2025 14:30:48 -0500
Subject: [PATCH] fix #3508 - recheck min client count during idle callback
 (#3509)

---
 packages/pg-pool/index.js       |  6 ++++--
 packages/pg-pool/test/sizing.js | 16 ++++++++++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/packages/pg-pool/index.js b/packages/pg-pool/index.js
index b3d9ada9..3e505f79 100644
--- a/packages/pg-pool/index.js
+++ b/packages/pg-pool/index.js
@@ -372,8 +372,10 @@ class Pool extends EventEmitter {
     let tid
     if (this.options.idleTimeoutMillis && this._isAboveMin()) {
       tid = setTimeout(() => {
-        this.log('remove idle client')
-        this._remove(client, this._pulseQueue.bind(this))
+        if (this._isAboveMin()) {
+          this.log('remove idle client')
+          this._remove(client, this._pulseQueue.bind(this))
+        }
       }, this.options.idleTimeoutMillis)
 
       if (this.options.allowExitOnIdle) {
diff --git a/packages/pg-pool/test/sizing.js b/packages/pg-pool/test/sizing.js
index c237995a..0e93d737 100644
--- a/packages/pg-pool/test/sizing.js
+++ b/packages/pg-pool/test/sizing.js
@@ -124,3 +124,19 @@ describe('pool size of 2', () => {
     })
   )
 })
+
+describe('pool min size', () => {
+  it(
+    'does not drop below min when clients released at same time',
+    co.wrap(function* () {
+      const pool = new Pool({ max: 2, min: 1, idleTimeoutMillis: 10 })
+      const client = yield pool.connect()
+      const client2 = yield pool.connect()
+      client.release()
+      client2.release()
+      yield new Promise((resolve) => setTimeout(resolve, 20))
+      expect(pool.idleCount).to.equal(1)
+      return yield pool.end()
+    })
+  )
+})