4 files changed, 14 insertions, 18 deletions
diff --git a/includes/bootstrap.inc b/includes/bootstrap.inc
index d3c35b5f2..a394a7c75 100644
--- a/includes/bootstrap.inc
+++ b/includes/bootstrap.inc
@@ -444,10 +444,11 @@ function variable_get($name, $default) {
 function variable_set($name, $value) {
   global $conf;
 
-  db_lock_table('variable');
-  db_query("DELETE FROM {variable} WHERE name = '%s'", $name);
-  db_query("INSERT INTO {variable} (name, value) VALUES ('%s', '%s')", $name, serialize($value));
-  db_unlock_tables();
+  $serialized_value = serialize($value);
+  db_query("UPDATE {variable} SET value = '%s' WHERE name = '%s'", $serialized_value, $name);
+  if (!db_affected_rows()) {
+    @db_query("INSERT INTO {variable} (name, value) VALUES ('%s', '%s')", $name, $serialized_value);
+  }
 
   cache_clear_all('variables', 'cache');
 
diff --git a/includes/cache.inc b/includes/cache.inc
index 992b3749d..9bf209044 100644
--- a/includes/cache.inc
+++ b/includes/cache.inc
@@ -104,12 +104,11 @@ function cache_set($cid, $data, $table = 'cache', $expire = CACHE_PERMANENT, $he
     $data = serialize($data);
     $serialized = 1;
   }
-  db_lock_table($table);
-  db_query("UPDATE {". $table ."} SET data = %b, created = %d, expire = %d, headers = '%s', serialized = %d WHERE cid = '%s'", $data, time(), $expire, $headers, $serialized, $cid);
+  $created = time();
+  db_query("UPDATE {". $table ."} SET data = %b, created = %d, expire = %d, headers = '%s', serialized = %d WHERE cid = '%s'", $data, $created, $expire, $headers, $serialized, $cid);
   if (!db_affected_rows()) {
-    @db_query("INSERT INTO {". $table ."} (cid, data, created, expire, headers, serialized) VALUES ('%s', %b, %d, %d, '%s', %d)", $cid, $data, time(), $expire, $headers, $serialized);
+    @db_query("INSERT INTO {". $table ."} (cid, data, created, expire, headers, serialized) VALUES ('%s', %b, %d, %d, '%s', %d)", $cid, $data, $created, $expire, $headers, $serialized);
   }
-  db_unlock_tables();
 }
 
 /**
diff --git a/includes/database.mysql.inc b/includes/database.mysql.inc
index 166017621..45426fff2 100644
--- a/includes/database.mysql.inc
+++ b/includes/database.mysql.inc
@@ -250,13 +250,11 @@ function db_error() {
  * with table prefixes. For example, db_next_id('{node}_nid');
  */
 function db_next_id($name) {
+  global $active_db;
   $name = db_prefix_tables($name);
-  db_query('LOCK TABLES {sequences} WRITE');
-  $id = db_result(db_query("SELECT id FROM {sequences} WHERE name = '%s'", $name)) + 1;
-  db_query("REPLACE INTO {sequences} VALUES ('%s', %d)", $name, $id);
-  db_query('UNLOCK TABLES');
+  db_query('INSERT INTO {sequences} VALUES ("%s", LAST_INSERT_ID(1)) ON DUPLICATE KEY UPDATE id = LAST_INSERT_ID(id + 1)', $name);
 
-  return $id;
+  return mysql_insert_id($active_db);
 }
 
 /**
diff --git a/includes/database.mysqli.inc b/includes/database.mysqli.inc
index ad58a6f24..baac124de 100644
--- a/includes/database.mysqli.inc
+++ b/includes/database.mysqli.inc
@@ -242,13 +242,11 @@ function db_error() {
  * with table prefixes. For example, db_next_id('{node}_nid');
  */
 function db_next_id($name) {
+  global $active_db;
   $name = db_prefix_tables($name);
-  db_query('LOCK TABLES {sequences} WRITE');
-  $id = db_result(db_query("SELECT id FROM {sequences} WHERE name = '%s'", $name)) + 1;
-  db_query("REPLACE INTO {sequences} VALUES ('%s', %d)", $name, $id);
-  db_query('UNLOCK TABLES');
+  db_query('INSERT INTO {sequences} VALUES ("%s", LAST_INSERT_ID(1)) ON DUPLICATE KEY UPDATE id = LAST_INSERT_ID(id + 1)', $name);
 
-  return $id;
+  return mysqli_insert_id($active_db);
 }
 
 /**