WL#8350: ENSURE 5.7 SUPPORTS SMOOTH LIVE UPGRADE FROM 5.6
Affects: Server-5.7 — Status: Complete — Priority: Medium
The upgrade procedure from 5.6 to 5.7 should be : 1. stop the 5.6 server. 2. upgrade the binaries 3. run the 5.7 server over the 5.6 server's database with *no* special options 4. run 5.7's version of mysql_upgrade 5. restart the server. Nothing more, nothing less.
F-1: During the upgrade process the 5.7 binaries should work with 5.6 database layout without specifying --skip-grant-tables option. In order to achieve this the authentication process during the update need to make use of mysql.user table in the following way: NF-1: If plugin field is empty and password length (=16 bytes) indicates mysql_old_password plugin we skip this account as the support for mysql_old_password was removed in 5.7 NF-2: If plugin field is empty and password length (= 41 bytes) indicates mysql_native_password plugin we use this account as if plugin field was equal to mysql_native_password. NF-3: If plugin field is not empty and the authentication string is not empty we use authentication string to validate the user (instead of using password when available - current behavior) NF-4: During the update - the server needs to automatically verify whether it is working with 5.6 database layout and if so execute the above scenario. NF-5: The above scenario will only work for starting the server (acl_load()) and for FLUSH PRIVILEGES (acl_reload()). NF-6: No user manipulation commands (e.g. ALTER USER/SET PASSWORD etc) will work on the non-upgraded users. The changes between 5.6 and 5.7 mysql.user table that interest us are - the plugin filed cannot be null and password field has been removed.
See the related BUG#75723
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