MDEV-20320 Tablespace flags mismatch for full_crc32 format

Files for PAGE_COMPRESSED tables that were created with
innodb_checksum_algorithm=full_crc32 store the value of
innodb_compression_algorithm at the time of the file creation.

The server-wide setting of innodb_compression_algorithm
may be changed after file creation. We must ignore any mismatch
when opening a data file, and for writes, we must use the
choice of algorithm that is stored in the file.

fil_space_t::is_flags_full_crc32_equal(): Ignore the
innodb_compression_algorithm but do compare innodb_page_size.

fil_space_t::is_flags_non_full_crc32_equal(): Ignore the
innodb_compression_algorithm.

3 files changed, 117 insertions, 5 deletions

diff --git a/mysql-test/suite/innodb/r/full_crc32_import.result b/mysql-test/suite/innodb/r/full_crc32_import.result
index 693ad22bab6..b8ebbb73706 100644
--- a/mysql-test/suite/innodb/r/full_crc32_import.result
+++ b/mysql-test/suite/innodb/r/full_crc32_import.result
@@ -127,3 +127,51 @@ Table	Op	Msg_type	Msg_text
 test.t1	check	status	OK
 InnoDB		0 transactions not purged
 DROP TABLE t1;
+SET @save_algo = @@GLOBAL.innodb_compression_algorithm;
+SET GLOBAL innodb_compression_algorithm=2;
+CREATE TABLE t1(a SERIAL) PAGE_COMPRESSED=1 ENGINE=InnoDB;
+INSERT INTO t1 VALUES(1);
+FLUSH TABLE t1 FOR EXPORT;
+# List before copying files
+db.opt
+t1.cfg
+t1.frm
+t1.ibd
+backup: t1
+UNLOCK TABLES;
+SET GLOBAL innodb_compression_algorithm=0;
+ALTER TABLE t1 FORCE;
+ALTER TABLE t1 DISCARD TABLESPACE;
+db.opt
+t1.frm
+restore: t1 .ibd and .cfg files
+ALTER TABLE t1 IMPORT TABLESPACE;
+INSERT INTO t1 VALUES(2);
+SELECT * FROM t1;
+a
+1
+2
+SET GLOBAL innodb_compression_algorithm=3;
+FLUSH TABLE t1 FOR EXPORT;
+# List before copying files
+db.opt
+t1.cfg
+t1.frm
+t1.ibd
+backup: t1
+UNLOCK TABLES;
+SET GLOBAL innodb_compression_algorithm=0;
+ALTER TABLE t1 FORCE;
+ALTER TABLE t1 DISCARD TABLESPACE;
+db.opt
+t1.frm
+restore: t1 .ibd and .cfg files
+ALTER TABLE t1 IMPORT TABLESPACE;
+INSERT INTO t1 VALUES(3);
+SELECT * FROM t1;
+a
+1
+2
+3
+DROP TABLE t1;
+SET GLOBAL innodb_compression_algorithm=@save_algo;
diff --git a/mysql-test/suite/innodb/t/full_crc32_import.test b/mysql-test/suite/innodb/t/full_crc32_import.test
index 3916b52d073..c5b50997a70 100644
--- a/mysql-test/suite/innodb/t/full_crc32_import.test
+++ b/mysql-test/suite/innodb/t/full_crc32_import.test
@@ -137,3 +137,64 @@ DELETE FROM t1;
 CHECK TABLE t1;
 --source include/wait_all_purged.inc
 DROP TABLE t1;
+
+SET @save_algo = @@GLOBAL.innodb_compression_algorithm;
+SET GLOBAL innodb_compression_algorithm=2;
+CREATE TABLE t1(a SERIAL) PAGE_COMPRESSED=1 ENGINE=InnoDB;
+INSERT INTO t1 VALUES(1);
+
+FLUSH TABLE t1 FOR EXPORT;
+--echo # List before copying files
+let MYSQLD_DATADIR =`SELECT @@datadir`;
+
+--list_files $MYSQLD_DATADIR/test
+perl;
+do "$ENV{MTR_SUITE_DIR}/include/innodb-util.pl";
+ib_backup_tablespaces("test", "t1");
+EOF
+
+UNLOCK TABLES;
+SET GLOBAL innodb_compression_algorithm=0;
+ALTER TABLE t1 FORCE;
+ALTER TABLE t1 DISCARD TABLESPACE;
+
+--list_files $MYSQLD_DATADIR/test
+perl;
+do "$ENV{MTR_SUITE_DIR}/include/innodb-util.pl";
+ib_discard_tablespaces("test", "t1");
+ib_restore_tablespaces("test", "t1");
+EOF
+
+ALTER TABLE t1 IMPORT TABLESPACE;
+INSERT INTO t1 VALUES(2);
+SELECT * FROM t1;
+
+SET GLOBAL innodb_compression_algorithm=3;
+FLUSH TABLE t1 FOR EXPORT;
+--echo # List before copying files
+let MYSQLD_DATADIR =`SELECT @@datadir`;
+
+--list_files $MYSQLD_DATADIR/test
+perl;
+do "$ENV{MTR_SUITE_DIR}/include/innodb-util.pl";
+ib_backup_tablespaces("test", "t1");
+EOF
+
+UNLOCK TABLES;
+SET GLOBAL innodb_compression_algorithm=0;
+ALTER TABLE t1 FORCE;
+ALTER TABLE t1 DISCARD TABLESPACE;
+
+--list_files $MYSQLD_DATADIR/test
+perl;
+do "$ENV{MTR_SUITE_DIR}/include/innodb-util.pl";
+ib_discard_tablespaces("test", "t1");
+ib_restore_tablespaces("test", "t1");
+EOF
+
+ALTER TABLE t1 IMPORT TABLESPACE;
+INSERT INTO t1 VALUES(3);
+SELECT * FROM t1;
+DROP TABLE t1;
+
+SET GLOBAL innodb_compression_algorithm=@save_algo;
diff --git a/storage/innobase/include/fil0fil.h b/storage/innobase/include/fil0fil.h
index 04c7f4f18d1..a876076999d 100644
--- a/storage/innobase/include/fil0fil.h
+++ b/storage/innobase/include/fil0fil.h
@@ -395,13 +395,16 @@ struct fil_space_t {
 	static bool is_flags_full_crc32_equal(ulint flags, ulint expected)
 	{
 		ut_ad(full_crc32(flags));
+		ulint page_ssize = FSP_FLAGS_FCRC32_GET_PAGE_SSIZE(flags);
 
 		if (full_crc32(expected)) {
-			return get_compression_algo(flags)
-				== get_compression_algo(expected);
+			/* The data file may have been created with a
+			different innodb_compression_algorithm. But
+			we only support one innodb_page_size for all files. */
+			return page_ssize
+				== FSP_FLAGS_FCRC32_GET_PAGE_SSIZE(expected);
 		}
 
-		ulint page_ssize = FSP_FLAGS_FCRC32_GET_PAGE_SSIZE(flags);
 		ulint space_page_ssize = FSP_FLAGS_GET_PAGE_SSIZE(expected);
 
 		if (page_ssize == 5) {
@@ -412,7 +415,7 @@ struct fil_space_t {
 			return false;
 		}
 
-		return is_compressed(expected) == is_compressed(flags);
+		return true;
 	}
 	/** Whether old tablespace flags match full_crc32 flags.
 	@param[in]	flags		flags present
@@ -438,7 +441,7 @@ struct fil_space_t {
 			return false;
 		}
 
-		return is_compressed(expected) == is_compressed(flags);
+		return true;
 	}
 	/** Whether both fsp flags are equivalent */
 	static bool is_flags_equal(ulint flags, ulint expected)