MariaDB Server 10.0.28 and 10.1.19 merged code from Percona XtraDB
that introduced support for compressed columns. Much but not all
of this code was disabled by placing #ifdef HAVE_PERCONA_COMPRESSED_COLUMNS
around it.
Among the unused but not disabled code is code to access
some new system tables related to compressed columns.
The creation of these system tables SYS_ZIP_DICT and SYS_ZIP_DICT_COLS
would cause a crash in --innodb-read-only mode when upgrading
from an earlier version to 10.0.28 or 10.1.19.
Let us remove all the dead code related to compressed columns.
Users who already upgraded to 10.0.28 and 10.1.19 will have the two
above mentioned empty tables in their InnoDB system tablespace.
Subsequent versions of MariaDB Server will completely ignore those tables.
change buffer not empty
Fix: Allow not empty change buffer when innodb_force_recovery >= 5
and output only a warning to error log.
Note: Before using force recovery you should always take backup
of your database.
There was two problems. Firstly, if page in ibuf is encrypted but
decrypt failed we should not allow InnoDB to start because
this means that system tablespace is encrypted and not usable.
Secondly, if page decrypt is detected we should return false
from buf_page_decrypt_after_read.
