X-Git-Url: https://vcs.fsf.org/?a=blobdiff_plain;f=CRM%2FUtils%2FSQL.php;h=8c7f4c6938545c431fc53fe83670e22084e654c4;hb=67dd8c7cb0c00d3775de0d8a356b8f1d9cb63cb0;hp=a20dc3800bd485108b9533bbde83aa29f2ec1b6e;hpb=6b83d5bdd0f2ca546924feae6aa42aeddb1d40cf;p=civicrm-core.git

diff --git a/CRM/Utils/SQL.php b/CRM/Utils/SQL.php
index a20dc3800b..8c7f4c6938 100644
--- a/CRM/Utils/SQL.php
+++ b/CRM/Utils/SQL.php
@@ -44,7 +44,7 @@ class CRM_Utils_SQL {
     require_once 'api/v3/utils.php';
     $baoName = _civicrm_api3_get_BAO($entity);
     $bao = new $baoName();
-    $clauses = $subclauses = array();
+    $clauses = $subclauses = [];
     foreach ((array) $bao->addSelectWhereClause() as $field => $vals) {
       if ($vals && $field == $joinColumn) {
         $clauses = array_merge($clauses, (array) $vals);
@@ -78,7 +78,7 @@ class CRM_Utils_SQL {
    */
   public static function supportsFullGroupBy() {
     // CRM-21455 MariaDB 10.2 does not support ANY_VALUE
-    $version = CRM_Core_DAO::singleValueQuery('SELECT VERSION()');
+    $version = self::getDatabaseVersion();
 
     if (stripos($version, 'mariadb') !== FALSE) {
       return FALSE;
@@ -134,4 +134,42 @@ class CRM_Utils_SQL {
     return FALSE;
   }
 
+  /**
+   * Does the DB version support mutliple locks per
+   *
+   * https://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_get-lock
+   *
+   * As an interim measure we ALSO require CIVICRM_SUPPORT_MULTIPLE_LOCKS to be defined.
+   *
+   * This is a conservative measure to introduce the change which we expect to deprecate later.
+   *
+   * @todo we only check mariadb & mysql right now but maybe can add percona.
+   */
+  public static function supportsMultipleLocks() {
+    if (!defined('CIVICRM_SUPPORT_MULTIPLE_LOCKS')) {
+      return FALSE;
+    }
+    static $isSupportLocks = NULL;
+    if (!isset($isSupportLocks)) {
+      $version = self::getDatabaseVersion();
+      if (stripos($version, 'mariadb') !== FALSE) {
+        $isSupportLocks = version_compare($version, '10.0.2', '>=');
+      }
+      else {
+        $isSupportLocks = version_compare($version, '5.7.5', '>=');
+      }
+    }
+
+    return $isSupportLocks;
+  }
+
+  /**
+   * Get the version string for the database.
+   *
+   * @return string
+   */
+  public static function getDatabaseVersion() {
+    return CRM_Core_DAO::singleValueQuery('SELECT VERSION()');
+  }
+
 }