--source include/innodb_page_size.inc --source include/not_embedded.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 # SET GLOBAL innodb_purge_rseg_truncate_frequency = 1; CREATE TABLE t1(a INT PRIMARY KEY, b INT NOT NULL) ROW_FORMAT=REDUNDANT ENGINE=InnoDB; INSERT INTO t1 VALUES(1,2),(3,4); UPDATE t1 SET b=-3 WHERE a=3; # Initiate a full purge, which should reset all DB_TRX_ID. SET GLOBAL innodb_fast_shutdown=0; --source include/shutdown_mysqld.inc # 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=("a","DB_TRX_ID","DB_ROLL_PTR", "b"); 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 --source include/start_mysqld.inc SELECT * FROM t1; DROP TABLE t1;