MDEV#7383: engine-independent-stats column_stats has limited values for max/min values

Patch from Daniel Black:
- Change the charset of mysql.column_stats.{min_value, max_value} from
  utf8_bin varchar to varbinary
- Adjust the code that saves/reads the data accordingly.
- Also provide upgrade statement in mysql_system_tables_fix.sql

2 files changed, 3 insertions, 1 deletions

diff --git a/scripts/mysql_system_tables.sql b/scripts/mysql_system_tables.sql
index bc89ae82dbb..14b59bb3411 100644
--- a/scripts/mysql_system_tables.sql
+++ b/scripts/mysql_system_tables.sql
@@ -220,7 +220,7 @@ set @had_proxies_priv_table= @@warning_count != 0;
 
 CREATE TABLE IF NOT EXISTS table_stats (db_name varchar(64) NOT NULL, table_name varchar(64) NOT NULL, cardinality bigint(21) unsigned DEFAULT NULL, PRIMARY KEY (db_name,table_name) ) ENGINE=MyISAM CHARACTER SET utf8 COLLATE utf8_bin comment='Statistics on Tables';
 
-CREATE TABLE IF NOT EXISTS column_stats (db_name varchar(64) NOT NULL, table_name varchar(64) NOT NULL, column_name varchar(64) NOT NULL, min_value varchar(255) DEFAULT NULL, max_value varchar(255) DEFAULT NULL, nulls_ratio decimal(12,4) DEFAULT NULL, avg_length decimal(12,4) DEFAULT NULL, avg_frequency decimal(12,4) DEFAULT NULL, hist_size tinyint unsigned, hist_type enum('SINGLE_PREC_HB','DOUBLE_PREC_HB'), histogram varbinary(255), PRIMARY KEY (db_name,table_name,column_name) ) ENGINE=MyISAM CHARACTER SET utf8 COLLATE utf8_bin comment='Statistics on Columns';
+CREATE TABLE IF NOT EXISTS column_stats (db_name varchar(64) NOT NULL, table_name varchar(64) NOT NULL, column_name varchar(64) NOT NULL, min_value varbinary(255) DEFAULT NULL, max_value varbinary(255) DEFAULT NULL, nulls_ratio decimal(12,4) DEFAULT NULL, avg_length decimal(12,4) DEFAULT NULL, avg_frequency decimal(12,4) DEFAULT NULL, hist_size tinyint unsigned, hist_type enum('SINGLE_PREC_HB','DOUBLE_PREC_HB'), histogram varbinary(255), PRIMARY KEY (db_name,table_name,column_name) ) ENGINE=MyISAM CHARACTER SET utf8 COLLATE utf8_bin comment='Statistics on Columns';
 
 CREATE TABLE IF NOT EXISTS index_stats (db_name varchar(64) NOT NULL, table_name varchar(64) NOT NULL, index_name varchar(64) NOT NULL, prefix_arity int(11) unsigned NOT NULL, avg_frequency decimal(12,4) DEFAULT NULL, PRIMARY KEY (db_name,table_name,index_name,prefix_arity) ) ENGINE=MyISAM CHARACTER SET utf8 COLLATE utf8_bin comment='Statistics on Indexes';
 
diff --git a/scripts/mysql_system_tables_fix.sql b/scripts/mysql_system_tables_fix.sql
index 33b4306b103..f034af4f898 100644
--- a/scripts/mysql_system_tables_fix.sql
+++ b/scripts/mysql_system_tables_fix.sql
@@ -711,3 +711,5 @@ flush privileges;
 ALTER TABLE help_category MODIFY url TEXT NOT NULL;
 ALTER TABLE help_topic MODIFY url TEXT NOT NULL;
 
+# MDEV-7383 - varbinary on mix/max of column_stats
+alter table column_stats modify min_value varbinary(255) DEFAULT NULL, modify max_value varbinary(255) DEFAULT NULL;