Execution of server-side SQL statement 'CREATE SCHEMA mysql DEFAULT COLLATE utf8mb4_0900_ai_ci' failed after interrupting mysql installation

[shubham singh bohara]

was installing mysql.half done then interrupted.
started again then this error showed up

ProblemType: Package
DistroRelease: Ubuntu 19.10
Package: mysql-server-8.0 8.0.18-0ubuntu0.19.10.1
ProcVersionSignature: Ubuntu 5.3.0-23.25-generic 5.3.7
Uname: Linux 5.3.0-23-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu8.2
Architecture: amd64
Date: Sat Nov 30 23:08:35 2019
ErrorMessage: installed mysql-server-8.0 package post-installation script subprocess returned error exit status 1
InstallationDate: Installed on 2019-11-29 (1 days ago)
InstallationMedia: Ubuntu 19.10 "Eoan Ermine" - Release amd64 (20191017)
Logs.var.log.daemon.log:

Logs.var.log.mysql.error.log:
 2019-11-30T17:38:32.574432Z 0 [System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.18-0ubuntu0.19.10.1) starting as process 8394
 2019-11-30T17:38:32.851170Z 1 [ERROR] [MY-013178] [Server] Execution of server-side SQL statement 'CREATE SCHEMA mysql DEFAULT COLLATE utf8mb4_0900_ai_ci' failed with error code = 1049, error message = 'System schema directory does not exist.'.
 2019-11-30T17:38:32.852454Z 0 [ERROR] [MY-010020] [Server] Data Dictionary initialization failed.
 2019-11-30T17:38:32.853010Z 0 [ERROR] [MY-010119] [Server] Aborting
 2019-11-30T17:38:33.387831Z 0 [System] [MY-010910] [Server] /usr/sbin/mysqld: Shutdown complete (mysqld 8.0.18-0ubuntu0.19.10.1) (Ubuntu).
MySQLConf.etc.mysql.conf.d.mysql.cnf: [mysql]
MySQLConf.etc.mysql.conf.d.mysqldump.cnf:
 [mysqldump]
 quick
 quote-names
 max_allowed_packet = 16M
MySQLVarLibDirListing: ['server-cert.pem', 'ca.pem', 'public_key.pem', 'server-key.pem', 'client-cert.pem', 'ib_logfile0', 'performance_schema', 'ca-key.pem', 'debian-5.7.flag', 'ib_buffer_pool', 'binlog.000003', 'auto.cnf', 'private_key.pem', 'binlog.000004', 'sys', 'ib_logfile1', 'mysql.ibd', '#innodb_temp', 'binlog.000001', 'undo_002', 'binlog.000005', 'binlog.000002', 'binlog.index', 'client-key.pem', 'ibdata1', 'undo_001']
ProcCmdline: BOOT_IMAGE=/BOOT/ubuntu_qgn0bg@/vmlinuz-5.3.0-23-generic root=ZFS=rpool/ROOT/ubuntu_qgn0bg ro quiet splash vt.handoff=1
Python3Details: /usr/bin/python3.7, Python 3.7.5, python3-minimal, 3.7.5-1
PythonDetails: /usr/bin/python2.7, Python 2.7.17rc1, python-minimal, 2.7.17-1
RelatedPackageVersions:
 dpkg 1.19.7ubuntu2
 apt 1.9.4
SourcePackage: mysql-8.0
Title: package mysql-server-8.0 8.0.18-0ubuntu0.19.10.1 failed to install/upgrade: installed mysql-server-8.0 package post-installation script subprocess returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Eduardo Bonato (ebonato)]

Please look at bug #1899075 if it look similar to your use case.

[Christian Ehrhardt  (paelzer)]

@Eduardo - your bug 1899075 actually is bug 1612517 which you assumed already. But this bug here is not showing the the issue of "old configs no more working on upgrade" in the logs.