DDL sql execution error while upgrading from Moodle 3.4 to Moodle 3.5.1+ (SOLVED).

Here is the solution to DDL sql execution error ,while upgrading the Moodle 3.4 to Moodle 3.5.1+. The following is the copy of the error.

Upgrading to new version

search_simpledb

DDL sql execution error

More information about this error

×Debug info: Table 'mdl_search_simpledb_index' already exists
CREATE TABLE mdl_search_simpledb_index (
id BIGINT(10) NOT NULL auto_increment,
docid VARCHAR(255) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '',
itemid BIGINT(10) NOT NULL,
title LONGTEXT COLLATE utf8mb4_unicode_ci,
content LONGTEXT COLLATE utf8mb4_unicode_ci,
contextid BIGINT(10) NOT NULL,
areaid VARCHAR(255) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '',
type TINYINT(1) NOT NULL,
courseid BIGINT(10) NOT NULL,
owneruserid BIGINT(10),
modified BIGINT(10) NOT NULL,
userid BIGINT(10),
description1 LONGTEXT COLLATE utf8mb4_unicode_ci,
description2 LONGTEXT COLLATE utf8mb4_unicode_ci,
CONSTRAINT PRIMARY KEY (id)
, KEY mdl_searsimpinde_owncon2_ix (owneruserid, contextid)
, UNIQUE KEY mdl_searsimpinde_doc2_uix (docid)
)
ENGINE = InnoDB
DEFAULT COLLATE = utf8mb4_unicode_ci ROW_FORMAT=Compressed
COMMENT='search_simpledb table containing the index data.'
Error code: ddlexecuteerror

×Stack trace:

·         line 492 of /lib/dml/moodle_database.php: ddl_change_structure_exception thrown

·         line 1070 of /lib/dml/mysqli_native_moodle_database.php: call to moodle_database->query_end()

·         line 77 of /lib/ddl/database_manager.php: call to mysqli_native_moodle_database->change_database_structure()

·         line 425 of /lib/ddl/database_manager.php: call to database_manager->execute_sql_arr()

·         line 370 of /lib/ddl/database_manager.php: call to database_manager->install_from_xmldb_structure()

·         line 594 of /lib/upgradelib.php: call to database_manager->install_from_xmldb_file()

·         line 1857 of /lib/upgradelib.php: call to upgrade_plugins()

·         line 694 of /admin/index.php: call to upgrade_noncore()

SOLUTION:

1. Go to moodle root folder:  cd /var/www/html/moodle
2. vim config.php             //open the config file

             1 <?php  // Moodle configuration file
             2

             3 unset($CFG);

             4 global $CFG;

             5 $CFG = new stdClass();

             6

             7 $CFG->dbtype    = 'mysqli';

             8 $CFG->dblibrary = 'native';

             9 $CFG->dbhost    = 'localhost';

            10 $CFG->dbname    = 'moodledb';

            11 $CFG->dbuser    = 'username';

            12 $CFG->dbpass    = 'password123';

        13 $CFG->prefix    = 'mdl2_';

            14 $CFG->dboptions = array (

            15   'dbpersist' => 0,

            16   'dbport' => '',

            17   'dbsocket' => '',

            18   'dbcollation' => 'utf8mb4_unicode_ci',);

            20

            21 $CFG->wwwroot   = 'https://moodle.xxx.edu.bt';

            22 $CFG->dataroot  = '/var/mdata/moodledata';

            23 $CFG->admin     = 'admin';

            24

            25 $CFG->directorypermissions = 0777;

            26

            27 require_once(__DIR__ . '/lib/setup.php');

            28

            29 // There is no php closing tag in this file,

            30 // it is intentional because it prevents trailing whitespace problems!

             ~

On the config.php page, line no. 13 change the 

 $CFG->prefix    = 'mdl_';  to   $CFG->prefix    = 'mdl2_';

Refresh the page and you are good to go.