MDEV-34705: Binlog-in-engine: Read side of out-of-band binlogging

With this commit, the out-of-band binlogging of large event groups in
multiple smaller records interleaved with other event groups is now working.

Instead of flushing the binlog cache to disk when they reach
@@binlog_cache_size, instead the cache is binlogged as an out-of-band
record. Then at transaction commit, a commit record is written containing
just the GTID and a link to the out-of-band data.

To facilitate append-only operation, the binlogged records do not have a
"next" pointer. Instead, they are written out as a forest of perfect binary
trees, the leftmost leaf of one tree pointing to the root of the previous
tree. This structure is used in the binlog reader to efficiently read out
the event group data consecutively for the binlog dump thread, needing to
maintain only O(log(N)) amount of memory during the reading.

As part of this commit, the existing binlog reader code is refactored to be
greatly improved, with a much cleaner explicit state machine and handling of
chunk/page/file boundaries etc.

Also fixes some bugs in the gtid_search::find_gtid_pos().

Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

mysql-test/suite/binlog_in_engine/rpl_oob.result

@@ -0,0 +1,19 @@
+include/master-slave.inc
+[connection master]
+CREATE TABLE t1 (a INT NOT NULL, b INT NOT NULL, c TEXT, PRIMARY KEY(a, b)) ENGINE=InnoDB;
+INSERT INTO t1 VALUES (0, 0, 'Start');
+*** Generating 25 large transactions in 5 interleaved connections
+connection master;
+INSERT INTO t1 VALUES (0, 1, 'End');
+SELECT COUNT(*), SUM(a), SUM(b), SUM(LENGTH(c)) FROM t1;
+COUNT(*)	SUM(a)	SUM(b)	SUM(LENGTH(c))
+2552	33150	128776	5000383
+include/save_master_gtid.inc
+connection slave;
+include/sync_with_master_gtid.inc
+SELECT COUNT(*), SUM(a), SUM(b), SUM(LENGTH(c)) FROM t1;
+COUNT(*)	SUM(a)	SUM(b)	SUM(LENGTH(c))
+2552	33150	128776	5000383
+connection master;
+DROP TABLE t1;
+include/rpl_end.inc

mysql-test/suite/binlog_in_engine/rpl_oob.test

@@ -0,0 +1,69 @@
+--source include/have_innodb_binlog.inc
+--source include/have_binlog_format_row.inc
+--source include/master-slave.inc
+
+# Test a number of transactions that are large and get interleaved with each
+# other over multiple binlog files.
+--let $NUM_CONNECTIONS= 5
+# $NUM_TRANSACTIONS is total, not per connection.
+--let $NUM_TRANSACTIONS=25
+--let $NUM_PIECES= 100
+--let $PIECE_SIZE= 2000
+
+
+CREATE TABLE t1 (a INT NOT NULL, b INT NOT NULL, c TEXT, PRIMARY KEY(a, b)) ENGINE=InnoDB;
+INSERT INTO t1 VALUES (0, 0, 'Start');
+
+--echo *** Generating $NUM_TRANSACTIONS large transactions in $NUM_CONNECTIONS interleaved connections
+--disable_query_log
+let $t= 0;
+while ($t < $NUM_TRANSACTIONS) {
+  let $b= $t;
+  let $i= 1;
+  while ($i <= $NUM_CONNECTIONS) {
+    --connect(con$i,localhost,root,,)
+    START TRANSACTION;
+    eval INSERT INTO t1 VALUES ($b + $i, 0, 'Initial $i');
+    inc $i;
+    inc $t;
+  }
+
+  let $p= 1;
+  while ($p <= $NUM_PIECES) {
+    let $i= 1;
+    while ($i <= $NUM_CONNECTIONS) {
+      --connection con$i
+      eval INSERT INTO t1 VALUES ($b + $i, $p, REPEAT(CHR(65 + ($p + $i MOD 26)), $PIECE_SIZE));
+      inc $i;
+    }
+    inc $p;
+  }
+
+  let $i= 1;
+  while ($i <= $NUM_CONNECTIONS) {
+    --connection con$i
+    eval INSERT INTO t1 VALUES ($b + $i, $NUM_PIECES+1, 'Last $i');
+    COMMIT;
+    --disconnect con$i
+    inc $i;
+  }
+}
+--enable_query_log
+
+--connection master
+INSERT INTO t1 VALUES (0, 1, 'End');
+
+SELECT COUNT(*), SUM(a), SUM(b), SUM(LENGTH(c)) FROM t1;
+--source include/save_master_gtid.inc
+--exec $MYSQL_BINLOG --read-from-remote-server --user=root --host=127.0.0.1 --port=$MASTER_MYPORT master-bin.000001 --start-position=0-1-1 > $MYSQLTEST_VARDIR/tmp/mysqlbinlog.txt
+
+--connection slave
+--source include/sync_with_master_gtid.inc
+SELECT COUNT(*), SUM(a), SUM(b), SUM(LENGTH(c)) FROM t1;
+
+
+# Cleanup.
+--connection master
+DROP TABLE t1;
+--exec $MYSQL_BINLOG --read-from-remote-server --user=root --host=127.0.0.1 --port=$MASTER_MYPORT master-bin.000001 --start-position=0-1-1 > $MYSQLTEST_VARDIR/tmp/mysqlbinlog.txt
+--source include/rpl_end.inc