--source include/innodb_page_size.inc

let INNODB_PAGE_SIZE=`select @@innodb_page_size`;
let MYSQLD_DATADIR=`select @@datadir`;
SET @saved_frequency = @@GLOBAL.innodb_purge_rseg_truncate_frequency;
SET GLOBAL innodb_purge_rseg_truncate_frequency = 1;

--echo #
--echo # MDEV-12288 Reset DB_TRX_ID when the history is removed,
--echo # to speed up MVCC
--echo #

SET GLOBAL innodb_purge_rseg_truncate_frequency = 1;

CREATE TABLE t1(a INT PRIMARY KEY, b INT NOT NULL)
ROW_FORMAT=REDUNDANT ENGINE=InnoDB;
--source include/wait_all_purged.inc

--connect (prevent_purge,localhost,root)
START TRANSACTION WITH CONSISTENT SNAPSHOT;

--connection default
INSERT INTO t1 VALUES(1,2),(3,4);
ALTER TABLE t1 ADD COLUMN c INT;
UPDATE t1 SET b=-3 WHERE a=3;

--connect (con1,localhost,root)
BEGIN;
# For purgeable records, we must record DB_TRX_ID=0 in the undo log!
UPDATE t1 SET b=4 WHERE a=3;
--disconnect prevent_purge

--connection default
# Initiate a full purge, which should reset the DB_TRX_ID except for a=3.
--source include/wait_all_purged.inc
# Initiate a ROLLBACK of the update, which should reset the DB_TRX_ID for a=3.
--connection con1
ROLLBACK;
--disconnect con1
--connection default
# Reset the DB_TRX_ID for the hidden ADD COLUMN metadata record.
--source include/wait_all_purged.inc

FLUSH TABLE t1 FOR EXPORT;
# The following is based on innodb.table_flags:
--perl
use strict;
my $ps= $ENV{INNODB_PAGE_SIZE};
my $file= "$ENV{MYSQLD_DATADIR}/test/t1.ibd";
open(FILE, "<", $file) || die "Unable to open $file\n";
my $page;
print "Clustered index root page contents:\n";
sysseek(FILE, 3*$ps, 0) || die "Unable to seek $file";
die "Unable to read $file" unless sysread(FILE, $page, $ps) == $ps;
print "N_RECS=", unpack("n", substr($page,38+16,2));
print "; LEVEL=", unpack("n", substr($page,38+26,2)), "\n";
my @fields=qw(a DB_TRX_ID DB_ROLL_PTR b c);
for (my $offset= 0x65; $offset;
     $offset= unpack("n", substr($page,$offset-2,2)))
{
    print "header=0x", unpack("H*",substr($page,$offset-6,6)), " (";
    my $n_fields= unpack("n", substr($page,$offset-4,2)) >> 1 & 0x3ff;
    my $start= 0;
    my $name;
    for (my $i= 0; $i < $n_fields; $i++) {
	my $end= unpack("C", substr($page, $offset-7-$i, 1));
	print ",\n " if $i;
	print "$fields[$i]=";
	if ($end & 0x80) {
	    print "NULL(", ($end & 0x7f) - $start, " bytes)"
	} else {
	    print "0x", unpack("H*", substr($page,$offset+$start,$end-$start))
	}
	$start= $end & 0x7f;
    }
    print ")\n";
}
close(FILE) || die "Unable to close $file\n";
EOF
UNLOCK TABLES;
SELECT * FROM t1;
DROP TABLE t1;
SET GLOBAL innodb_purge_rseg_truncate_frequency = @saved_frequency;