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--source include/innodb_page_size.inc
let INNODB_PAGE_SIZE=`select @@innodb_page_size`;
let MYSQLD_DATADIR=`select @@datadir`;
--echo #
--echo # MDEV-12288 Reset DB_TRX_ID when the history is removed,
--echo # to speed up MVCC
--echo #
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.
SET GLOBAL innodb_max_purge_lag_wait=1;
# 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;
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