Merge branch 'MDL-39725_analyze' of https://github.com/mr-russ/moodle

Conflicts:
	lib/dml/moodle_database.php

lib/ddl/tests/ddl_test.php

@@ -1545,6 +1545,9 @@ class core_ddl_testcase extends database_driver_testcase {
         $this->assertSame($records[1]->secondname, $this->records['test_table1'][0]->secondname);
         $this->assertSame($records[2]->intro, $this->records['test_table1'][1]->intro);
 
+        // Collect statistics about the data in the temp table.
+        $DB->update_temp_table_stats();
+
         // Drop table1.
         $dbman->drop_table($table1);
         $this->assertFalse($dbman->table_exists('test_table1'));
@@ -1558,6 +1561,9 @@ class core_ddl_testcase extends database_driver_testcase {
             $this->assertInstanceOf('ddl_table_missing_exception', $e);
         }
 
+        // Collect statistics about the data in the temp table with less tables.
+        $DB->update_temp_table_stats();
+
         // Fill/modify/delete a few table0 records.
 
         // Drop table0.

lib/dml/moodle_database.php

@@ -2172,6 +2172,15 @@ abstract class moodle_database {
         }
     }
 
+    /**
+     * Analyze the data in temporary tables to force statistics collection after bulk data loads.
+     *
+     * @return void
+     */
+    public function update_temp_table_stats() {
+        $this->temptables->update_stats();
+    }
+
     /**
      * Checks and returns true if transactions are supported.
      *

lib/dml/moodle_temptables.php

@@ -22,6 +22,7 @@
  *
  *   - databases not retrieving temp tables from information schema tables (mysql)
  *   - databases using a different name schema for temp tables (like mssql).
+ *   - databases that don't collect planner stats for temp tables (like PgSQL).
  *
  * Basically it works as a simple store of created temporary tables, providing
  * some simple getters/setters methods. Each database can extend it for its own
@@ -31,9 +32,6 @@
  * and the sql_generator, so both are able to use its facilities, with the final goal
  * of doing temporary tables support 100% cross-db and transparent within the DB API.
  *
- * Only drivers needing it will use this store. Neither moodle_database (abstract) or
- * databases like postgres need this, because they don't lack any temp functionality.
- *
  * @package    core_dml
  * @copyright  2009 onwards Eloy Lafuente (stronk7) {@link http://stronk7.com}
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
@@ -119,6 +117,17 @@ class moodle_temptables {
         return null;
     }
 
+    /**
+     * Analyze the data in temporary tables to force statistics collection after bulk data loads.
+     * The database class detects all temporary tables and will automatically analyze all created tables
+     *
+     * @return void
+     */
+    public function update_stats() {
+        // By default most databases do automatic on temporary tables, PgSQL does not.
+        // As a result, update_stats call immediately return for non-interesting database types.
+    }
+
     /**
      * Dispose the temptables stuff, checking for wrong situations, informing and recovering from them
      */

lib/dml/pgsql_native_moodle_temptables.php

@@ -29,5 +29,16 @@ defined('MOODLE_INTERNAL') || die();
 require_once(__DIR__.'/moodle_temptables.php');
 
 class pgsql_native_moodle_temptables extends moodle_temptables {
-    // I love these classes :-P
+    /**
+     * Analyze the data in temporary tables to force statistics collection after bulk data loads.
+     * PostgreSQL does not natively support automatic temporary table stats collection, so we do it.
+     *
+     * @return void
+     */
+    public function update_stats() {
+        $temptables = $this->get_temptables();
+        foreach ($temptables as $temptablename) {
+            $this->mdb->execute("ANALYZE {".$temptablename."}");
+        }
+    }
 }

lib/statslib.php

@@ -259,6 +259,7 @@ function stats_cron_daily($maxdays=1) {
             $failed = true;
             break;
         }
+        $DB->update_temp_table_stats();
 
         stats_progress('1');
 
@@ -385,6 +386,10 @@ function stats_cron_daily($maxdays=1) {
             $failed = true;
             break;
         }
+        // The steps up until this point, all add to {temp_stats_daily} and don't use new tables.
+        // There is no point updating statistics as they won't be used until the DELETE below.
+        $DB->update_temp_table_stats();
+
         stats_progress('7');
 
         // Default frontpage role enrolments are all site users (not deleted)
@@ -581,6 +586,7 @@ function stats_cron_daily($maxdays=1) {
             $failed = true;
             break;
         }
+        $DB->update_temp_table_stats();
         stats_progress('15');
 
         // How many view actions for guests or not-logged-in on frontpage
@@ -1736,6 +1742,9 @@ function stats_temp_table_fill($timestart, $timeend) {
 
     $DB->execute($sql);
 
+    // We have just loaded all the temp tables, collect statistics for that.
+    $DB->update_temp_table_stats();
+
     return true;
 }