MDEV-20142 encryption.innodb_encrypt_temporary_tables fails

The data type of the column INFORMATION_SCHEMA.GLOBAL_STATUS.VARIABLE_VALUE
is a character string. Therefore, if we want to compare some values as
integers, we must explicitly cast them to integer type, to avoid an
awkward comparison where '10'<'9' because the first digit is smaller.

mysql-test/suite/encryption/r/innodb_encrypt_temporary_tables.result

-SELECT variable_value into @old_encrypted FROM information_schema.global_status
+SELECT CAST(variable_value AS INT) INTO @old_encrypted
+FROM information_schema.global_status
 WHERE variable_name = 'innodb_encryption_n_temp_blocks_encrypted';
-SELECT variable_value into @old_decrypted FROM information_schema.global_status
+SELECT CAST(variable_value AS INT) INTO @old_decrypted
+FROM information_schema.global_status
 WHERE variable_name = 'innodb_encryption_n_temp_blocks_decrypted';
 CREATE TEMPORARY TABLE t1(f1 CHAR(200), f2 CHAR(200)) ENGINE=InnoDB;
 INSERT INTO t1 (f1,f2) SELECT '', '' FROM seq_1_to_8192;
@@ -12,11 +14,13 @@ COUNT(*)
 SELECT COUNT(*) FROM t2;
 COUNT(*)
 8192
-SELECT variable_value > @old_encrypted FROM information_schema.global_status
+SELECT CAST(variable_value AS INT) > @old_encrypted
+FROM information_schema.global_status
 WHERE variable_name = 'innodb_encryption_n_temp_blocks_encrypted';
-variable_value > @old_encrypted
+CAST(variable_value AS INT) > @old_encrypted
 1
-SELECT variable_value > @old_decrypted FROM information_schema.global_status
+SELECT CAST(variable_value AS INT) > @old_decrypted
+FROM information_schema.global_status
 WHERE variable_name = 'innodb_encryption_n_temp_blocks_decrypted';
-variable_value > @old_decrypted
+CAST(variable_value AS INT) > @old_decrypted
 1

mysql-test/suite/encryption/t/innodb_encrypt_temporary_tables.test

@@ -2,10 +2,12 @@
 --source include/have_innodb.inc
 --source include/have_file_key_management_plugin.inc
 
-SELECT variable_value into @old_encrypted FROM information_schema.global_status
+SELECT CAST(variable_value AS INT) INTO @old_encrypted
+FROM information_schema.global_status
 WHERE variable_name = 'innodb_encryption_n_temp_blocks_encrypted';
 
-SELECT variable_value into @old_decrypted FROM information_schema.global_status
+SELECT CAST(variable_value AS INT) INTO @old_decrypted
+FROM information_schema.global_status
 WHERE variable_name = 'innodb_encryption_n_temp_blocks_decrypted';
 
 CREATE TEMPORARY TABLE t1(f1 CHAR(200), f2 CHAR(200)) ENGINE=InnoDB;
@@ -17,8 +19,10 @@ INSERT INTO t2 (f1,f2,f3) SELECT '', '', '' FROM seq_1_to_8192;
 SELECT COUNT(*) FROM t1;
 SELECT COUNT(*) FROM t2;
 
-SELECT variable_value > @old_encrypted FROM information_schema.global_status
+SELECT CAST(variable_value AS INT) > @old_encrypted
+FROM information_schema.global_status
 WHERE variable_name = 'innodb_encryption_n_temp_blocks_encrypted';
 
-SELECT variable_value > @old_decrypted FROM information_schema.global_status
+SELECT CAST(variable_value AS INT) > @old_decrypted
+FROM information_schema.global_status
 WHERE variable_name = 'innodb_encryption_n_temp_blocks_decrypted';