From 4bd71f795fdba2f560913a982e562335584baf59 Mon Sep 17 00:00:00 2001
From: Nigro Simone <nigro.simone@gmail.com>
Date: Sun, 14 Dec 2025 19:30:43 +0100
Subject: [PATCH 1/3] refactor(client): replace query queue array with Deque
 for O(1) operations

---
 packages/pg/lib/client.js | 10 +++-----
 packages/pg/lib/deque.js  | 51 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+), 6 deletions(-)
 create mode 100644 packages/pg/lib/deque.js

diff --git a/packages/pg/lib/client.js b/packages/pg/lib/client.js
index 903db6c66..54a9213d5 100644
--- a/packages/pg/lib/client.js
+++ b/packages/pg/lib/client.js
@@ -11,6 +11,7 @@ const Query = require('./query')
 const defaults = require('./defaults')
 const Connection = require('./connection')
 const crypto = require('./crypto/utils')
+const Deque = require('./deque')
 
 const activeQueryDeprecationNotice = nodeUtils.deprecate(
   () => {},
@@ -79,7 +80,7 @@ class Client extends EventEmitter {
         keepAliveInitialDelayMillis: c.keepAliveInitialDelayMillis || 0,
         encoding: this.connectionParameters.client_encoding || 'utf8',
       })
-    this._queryQueue = []
+    this._queryQueue = new Deque()
     this.binary = c.binary || defaults.binary
     this.processID = null
     this.secretKey = null
@@ -124,7 +125,7 @@ class Client extends EventEmitter {
     }
 
     this._queryQueue.forEach(enqueueError)
-    this._queryQueue.length = 0
+    this._queryQueue.clear()
   }
 
   _connect(callback) {
@@ -608,10 +609,7 @@ class Client extends EventEmitter {
         query.callback = () => {}
 
         // Remove from queue
-        const index = this._queryQueue.indexOf(query)
-        if (index > -1) {
-          this._queryQueue.splice(index, 1)
-        }
+        this._queryQueue.remove(query)
 
         this._pulseQueryQueue()
       }, readTimeout)
diff --git a/packages/pg/lib/deque.js b/packages/pg/lib/deque.js
new file mode 100644
index 000000000..3d5050851
--- /dev/null
+++ b/packages/pg/lib/deque.js
@@ -0,0 +1,51 @@
+class Deque {
+  constructor() {
+    this._store = Object.create(null)
+    this._head = 0
+    this._tail = 0
+  }
+
+  push(item) {
+    this._store[this._tail++] = item
+  }
+
+  shift() {
+    if (this._head === this._tail) return undefined
+    const item = this._store[this._head]
+    delete this._store[this._head++]
+    return item
+  }
+
+  get length() {
+    return this._tail - this._head
+  }
+
+  clear() {
+    this._store = Object.create(null)
+    this._head = 0
+    this._tail = 0
+  }
+
+  remove(item) {
+    const newStore = Object.create(null)
+    const newHead = 0
+    let newTail = 0
+    for (let i = this._head; i < this._tail; i++) {
+      const current = this._store[i]
+      if (current !== item) {
+        newStore[newTail++] = current
+      }
+    }
+    this._store = newStore
+    this._head = newHead
+    this._tail = newTail
+  }
+
+  forEach(fn) {
+    for (let i = this._head; i < this._tail; i++) {
+      fn(this._store[i], i)
+    }
+  }
+}
+
+module.exports = Deque

From d40e18c82d0d66ec7c1678c5db97c6f1580963d9 Mon Sep 17 00:00:00 2001
From: Nigro Simone <nigro.simone@gmail.com>
Date: Sun, 14 Dec 2025 19:51:23 +0100
Subject: [PATCH 2/3] perf: make stable object shapes

---
 packages/pg/lib/deque.js | 39 ++++++++++++++++++++++++++++-----------
 1 file changed, 28 insertions(+), 11 deletions(-)

diff --git a/packages/pg/lib/deque.js b/packages/pg/lib/deque.js
index 3d5050851..bca141c04 100644
--- a/packages/pg/lib/deque.js
+++ b/packages/pg/lib/deque.js
@@ -12,7 +12,14 @@ class Deque {
   shift() {
     if (this._head === this._tail) return undefined
     const item = this._store[this._head]
-    delete this._store[this._head++]
+    this._store[this._head] = undefined
+    this._head++
+
+    if (this._head === this._tail) {
+      this._head = 0
+      this._tail = 0
+    }
+
     return item
   }
 
@@ -27,23 +34,33 @@ class Deque {
   }
 
   remove(item) {
-    const newStore = Object.create(null)
-    const newHead = 0
-    let newTail = 0
-    for (let i = this._head; i < this._tail; i++) {
-      const current = this._store[i]
+    if (this._head === this._tail) return
+
+    const store = this._store
+    let write = this._head
+
+    for (let read = this._head; read < this._tail; read++) {
+      const current = store[read]
       if (current !== item) {
-        newStore[newTail++] = current
+        store[write++] = current
       }
     }
-    this._store = newStore
-    this._head = newHead
-    this._tail = newTail
+
+    for (let i = write; i < this._tail; i++) {
+      store[i] = undefined
+    }
+
+    this._tail = write
+
+    if (this._head === this._tail) {
+      this._head = 0
+      this._tail = 0
+    }
   }
 
   forEach(fn) {
     for (let i = this._head; i < this._tail; i++) {
-      fn(this._store[i], i)
+      fn(this._store[i])
     }
   }
 }

From 17158e6b8afd17fe2e3897a0a3f4c043104fb26f Mon Sep 17 00:00:00 2001
From: Nigro Simone <nigro.simone@gmail.com>
Date: Mon, 15 Dec 2025 21:51:02 +0100
Subject: [PATCH 3/3] chore: make remove O(1)

---
 packages/pg/lib/deque.js | 87 +++++++++++++++++++++++-----------------
 1 file changed, 51 insertions(+), 36 deletions(-)

diff --git a/packages/pg/lib/deque.js b/packages/pg/lib/deque.js
index bca141c04..dfb5db1e0 100644
--- a/packages/pg/lib/deque.js
+++ b/packages/pg/lib/deque.js
@@ -1,66 +1,81 @@
 class Deque {
   constructor() {
-    this._store = Object.create(null)
-    this._head = 0
-    this._tail = 0
+    this._head = null
+    this._tail = null
+    this._size = 0
+    this._index = new WeakMap()
   }
 
   push(item) {
-    this._store[this._tail++] = item
+    const node = { value: item, prev: this._tail, next: null }
+
+    if (this._tail) {
+      node.prev = this._tail
+      this._tail.next = node
+      this._tail = node
+    } else {
+      this._head = this._tail = node
+    }
+
+    this._index.set(item, node)
+    this._size++
   }
 
   shift() {
-    if (this._head === this._tail) return undefined
-    const item = this._store[this._head]
-    this._store[this._head] = undefined
-    this._head++
-
-    if (this._head === this._tail) {
-      this._head = 0
-      this._tail = 0
+    if (!this._head) return undefined
+
+    const node = this._head
+    const value = node.value
+
+    this._head = node.next
+    if (this._head) {
+      this._head.prev = null
+    } else {
+      this._tail = null
     }
 
-    return item
+    this._index.delete(value)
+    this._size--
+
+    node.prev = node.next = null
+
+    return value
   }
 
   get length() {
-    return this._tail - this._head
+    return this._size
   }
 
   clear() {
-    this._store = Object.create(null)
-    this._head = 0
-    this._tail = 0
+    this._head = null
+    this._tail = null
+    this._size = 0
+    this._index = new WeakMap()
   }
 
   remove(item) {
-    if (this._head === this._tail) return
+    const node = this._index.get(item)
+    if (!node) return false
 
-    const store = this._store
-    let write = this._head
+    if (node.prev) node.prev.next = node.next
+    else this._head = node.next
 
-    for (let read = this._head; read < this._tail; read++) {
-      const current = store[read]
-      if (current !== item) {
-        store[write++] = current
-      }
-    }
+    if (node.next) node.next.prev = node.prev
+    else this._tail = node.prev
 
-    for (let i = write; i < this._tail; i++) {
-      store[i] = undefined
-    }
+    this._index.delete(item)
+    this._size--
 
-    this._tail = write
+    node.prev = node.next = null
 
-    if (this._head === this._tail) {
-      this._head = 0
-      this._tail = 0
-    }
+    return true
   }
 
   forEach(fn) {
-    for (let i = this._head; i < this._tail; i++) {
-      fn(this._store[i])
+    let curr = this._head
+    while (curr) {
+      fn(curr.value)
+      curr = curr.next
     }
   }
 }