From ecbc7faa7a089359cc5a7279ce9c925cb8efb9f6 Mon Sep 17 00:00:00 2001
From: Johno Crawford <johno.crawford@gmail.com>
Date: Mon, 6 Nov 2017 11:23:42 +0100
Subject: [PATCH] Fix for #88021 high GC pressure when driver configured with
 serversideprepared statements.

---
 src/com/mysql/jdbc/ConnectionImpl.java | 37 ++++++++++++----------------------
 1 file changed, 13 insertions(+), 24 deletions(-)

diff --git a/src/com/mysql/jdbc/ConnectionImpl.java b/src/com/mysql/jdbc/ConnectionImpl.java
index 14758ce9..e0fe1441 100644
--- a/src/com/mysql/jdbc/ConnectionImpl.java
+++ b/src/com/mysql/jdbc/ConnectionImpl.java
@@ -190,18 +190,17 @@ public class ConnectionImpl extends ConnectionPropertiesImpl implements MySQLCon
      * names soon will, so current catalog is a (hidden) component of the name.
      */
     static class CompoundCacheKey {
-        String componentOne;
+        final String componentOne;
 
-        String componentTwo;
+        final String componentTwo;
 
-        int hashCode;
+        final int hashCode;
 
         CompoundCacheKey(String partOne, String partTwo) {
             this.componentOne = partOne;
             this.componentTwo = partTwo;
-
             // Handle first component (in most cases, currentCatalog being NULL....
-            this.hashCode = (((this.componentOne != null) ? this.componentOne : "") + this.componentTwo).hashCode();
+            this.hashCode = 31 * (componentOne != null ? componentOne.hashCode() : 0) + (componentTwo != null ? componentTwo.hashCode() : 0);
         }
 
         /*
@@ -210,22 +209,15 @@ public class ConnectionImpl extends ConnectionPropertiesImpl implements MySQLCon
          * @see java.lang.Object#equals(java.lang.Object)
          */
         @Override
-        public boolean equals(Object obj) {
-            if (obj instanceof CompoundCacheKey) {
-                CompoundCacheKey another = (CompoundCacheKey) obj;
-
-                boolean firstPartEqual = false;
-
-                if (this.componentOne == null) {
-                    firstPartEqual = (another.componentOne == null);
-                } else {
-                    firstPartEqual = this.componentOne.equals(another.componentOne);
-                }
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
 
-                return (firstPartEqual && this.componentTwo.equals(another.componentTwo));
-            }
+            CompoundCacheKey that = (CompoundCacheKey) o;
 
-            return false;
+            if (componentOne != null ? !componentOne.equals(that.componentOne) : that.componentOne != null)
+                return false;
+            return componentTwo != null ? componentTwo.equals(that.componentTwo) : that.componentTwo == null;
         }
 
         /*
@@ -4277,11 +4269,8 @@ public class ConnectionImpl extends ConnectionPropertiesImpl implements MySQLCon
 
     }
 
-    private String makePreparedStatementCacheKey(String catalog, String query) {
-        StringBuilder key = new StringBuilder();
-        key.append("/*").append(catalog).append("*/");
-        key.append(query);
-        return key.toString();
+    private CompoundCacheKey makePreparedStatementCacheKey(String catalog, String query) {
+        return new CompoundCacheKey(catalog, query);
     }
 
     public void recachePreparedStatement(ServerPreparedStatement pstmt) throws SQLException {
-- 
2.13.6