Git commits in Moodle 3.9.0 by Mark Nelson

commit 7daa126d1ddb39f114f3989ba2896540f0471e36
Author: Mark Nelson <mdjnelson@gmail.com>
Date:   Mon, 20 Apr 2020 20:35:57 +0800
Tag:    v3.9.0-beta

MDL-58018 core: add support to database for read-only sessions

commit 4400ed3e1c4d6a411b857d1b3353839018ceb589
Author: Mark Nelson <mdjnelson@gmail.com>
Date:   Mon, 20 Apr 2020 20:35:50 +0800
Tag:    v3.9.0-beta

MDL-58018 core: finish dev to support open sessions without a lock

commit 39770792ca624a611eaaca6e973306938771fe83
Author: Mark Nelson <mdjnelson@gmail.com>
Date:   Mon, 20 Apr 2020 20:32:37 +0800
Tag:    v3.9.0-beta

MDL-58018 core: add support to redis for read-only sessions

commit 47f3fa131a99556106ea28505c05b63b18ed7163
Author: Mark Nelson <mdjnelson@gmail.com>
Date:   Thu, 02 Apr 2020 22:32:16 +0800
Tag:    v3.9.0-beta

MDL-67886 core: check_database_schema() checks for extra indexes

commit fad610045bb028801d7fddcf1019e3a64ddbfb4c
Author: Mark Nelson <mdjnelson@gmail.com>
Date:   Wed, 01 Apr 2020 03:08:07 +0800
Tag:    v3.9.0-beta

MDL-67886 tool_xmldb: checks for extra indexes

commit 52f993651caeb41709d3f86b0404147756b0f786
Author: Mark Nelson <mdjnelson@gmail.com>
Date:   Fri, 27 Mar 2020 06:19:19 +0800
Tag:    v3.9.0-beta

MDL-68193 core: added new database_text_field_content_replaced event

commit a8c38ce85ba1fc94ea61372a7416946c1afec29f
Author: Mark Nelson <mdjnelson@gmail.com>
Date:   Fri, 27 Mar 2020 01:06:41 +0800
Tag:    v3.9.0-beta

MDL-67886 core: check_database_schema() checks for missing indexes