MDL-53226 search_simpledb: Refine the patch

- Clumsy fallback only when there is no full-text search support
- Mimic solr tests
- pgsql tokenization using simple configuration
- workaround for mysql '*' search issue
- total results proper calculation
- SQL server FTS support
- Standarize dml full-text search checkings
- Upgrade note about the new dml method
- Set search_simpledb as default engine if no solr config

admin/settings/plugins.php

@@ -556,7 +556,7 @@
     // Search engine selection.
     $temp->add(new admin_setting_heading('searchengineheading', new lang_string('searchengine', 'admin'), ''));
     $temp->add(new admin_setting_configselect('searchengine',
-                                new lang_string('selectsearchengine', 'admin'), '', 'solr', $engines));
+                                new lang_string('selectsearchengine', 'admin'), '', 'simpledb', $engines));
     $temp->add(new admin_setting_heading('searchoptionsheading', new lang_string('searchoptions', 'admin'), ''));
     $temp->add(new admin_setting_configcheckbox('searchindexwhendisabled',
             new lang_string('searchindexwhendisabled', 'admin'), new lang_string('searchindexwhendisabled_desc', 'admin'),

lib/db/upgrade.php

@@ -2020,5 +2020,14 @@ function xmldb_main_upgrade($oldversion) {
         upgrade_main_savepoint(true, 2018022800.03);
     }
 
+    if ($oldversion < 2018031600.01) {
+
+        // Update default search engine to search_simpledb if global search is disabled and there is no solr index defined.
+        if (empty($CFG->enableglobalsearch) && empty(get_config('search_solr', 'indexname'))) {
+            set_config('searchengine', 'simpledb');
+        }
+        upgrade_main_savepoint(true, 2018031600.01);
+    }
+
     return true;
 }

lib/dml/mariadb_native_moodle_database.php

@@ -107,4 +107,18 @@ protected function transactions_supported() {
         }
         return true;
     }
+
+    /**
+     * Does this mariadb instance support fulltext indexes?
+     *
+     * @return bool
+     */
+    public function is_fulltext_search_supported() {
+        $info = $this->get_server_info();
+
+        if (version_compare($info['version'], '10.0.5', '>=')) {
+            return true;
+        }
+        return false;
+    }
 }

lib/dml/moodle_database.php

@@ -2687,4 +2687,14 @@ public function perf_get_queries() {
     public function perf_get_queries_time() {
         return $this->queriestime;
     }
+
+    /**
+     * Whether the database is able to support full-text search or not.
+     *
+     * @return bool
+     */
+    public function is_fulltext_search_supported() {
+        // No support unless specified.
+        return false;
+    }
 }

lib/dml/mysqli_native_moodle_database.php

@@ -1989,4 +1989,18 @@ public function convert_table_row_format($tablename) {
             $this->change_database_structure("ALTER TABLE {$prefix}$tablename $rowformat");
         }
     }
+
+    /**
+     * Does this mysql instance support fulltext indexes?
+     *
+     * @return bool
+     */
+    public function is_fulltext_search_supported() {
+        $info = $this->get_server_info();
+
+        if (version_compare($info['version'], '5.6.4', '>=')) {
+            return true;
+        }
+        return false;
+    }
 }

lib/dml/pgsql_native_moodle_database.php

@@ -1497,4 +1497,13 @@ protected function rollback_transaction() {
     private function trim_quotes($str) {
         return trim(trim($str), "'\"");
     }
+
+    /**
+     * Postgresql supports full-text search indexes.
+     *
+     * @return bool
+     */
+    public function is_fulltext_search_supported() {
+        return true;
+    }
 }

lib/dml/sqlsrv_native_moodle_database.php

@@ -1586,4 +1586,26 @@ protected function rollback_transaction() {
         $result = sqlsrv_rollback($this->sqlsrv);
         $this->query_end($result);
     }
+
+    /**
+     * Is fulltext search enabled?.
+     *
+     * @return bool
+     */
+    public function is_fulltext_search_supported() {
+        global $CFG;
+
+        $sql = "SELECT FULLTEXTSERVICEPROPERTY('IsFullTextInstalled')";
+        $this->query_start($sql, null, SQL_QUERY_AUX);
+        $result = sqlsrv_query($this->sqlsrv, $sql);
+        $this->query_end($result);
+        if ($result) {
+            if ($row = sqlsrv_fetch_array($result)) {
+                $property = (bool)reset($row);
+            }
+        }
+        $this->free_result($result);
+
+        return !empty($property);
+    }
 }

lib/upgrade.txt

@@ -22,6 +22,8 @@ information provided here is intended especially for developers.
 * Scripts can define a constant NO_SITEPOLICY_CHECK and set it to true before requiring the main config.php file. It
   will make the require_login() skipping the test for the user's policyagreed status. This is useful for plugins that
   act as a site policy handler.
+* There is a new is_fulltext_search_supported() DML function. The default implementation returns false. This function
+  is used by 'Simple search' global search engine to determine if the database full-text search capabilities can be used.
 
 === 3.4 ===
 

search/classes/document.php

@@ -407,8 +407,7 @@ public static function format_time_for_engine($timestamp) {
      * @return string
      */
     public static function format_string_for_engine($string) {
-        //FIXME: this shouldn't be required. Where is bad utf8 coming from?
-        return fix_utf8($string);
+        return $string;
     }
 
     /**
@@ -421,8 +420,7 @@ public static function format_string_for_engine($string) {
      * @return string
      */
     public static function format_text_for_engine($text) {
-        //FIXME: this shouldn't be required. Where is bad utf8 coming from?
-        return fix_utf8($text);
+        return $text;
     }
 
     /**