Bug#26117735: MYSQLBINLOG READ-FROM-REMOTE-SERVER NOT

HONORING REWRITE_DB FILTERING

Problem:
=======
When running mysqlbinlog with the --read-from-remote-server
option, the processing of the binlog entries accepts
rewrite_db as an argument, but ignores the rewrite rule.
Therefore no filtering is done on the binlog entries,
resulting in failures to write data in the target DB.

Analysis:
========
mysqlbinlog tool can read binary logs that are present
locally or on a remote machine. At present rewrite filter is
applied for binary logs that are read locally. This
rewrite_db filter specific code is not invoked while dumping
binary log from a remote machine. Hence the filtering is is
not done on those binlog entries.

Fix:
===
Invoke rewrite_db filter code while dumping remote log
entries as well.

Author: Sujatha Sivakumar

client/mysqlbinlog.cc

@@ -218,6 +218,7 @@ Query_log_event::rewrite_db_in_buffer(char **buf, ulong *event_len,
   char* ptr= *buf;
   uint sv_len= 0;
 
+  DBUG_EXECUTE_IF("simulate_corrupt_event_len", *event_len=0;);
   /* Error if the event content is too small */
   if (*event_len < (common_header_len + query_header_len))
     return true;
@@ -2532,7 +2533,8 @@ static Exit_status dump_remote_log_entries(PRINT_EVENT_INFO *print_event_info,
   char log_file_name[FN_REFLEN + 1];
   Exit_status retval= OK_CONTINUE;
   enum enum_server_command command= COM_END;
-
+  char *event_buf= NULL;
+  ulong event_len;
   DBUG_ENTER("dump_remote_log_entries");
 
   fname[0]= log_file_name[0]= 0;
@@ -2691,12 +2693,19 @@ static Exit_status dump_remote_log_entries(PRINT_EVENT_INFO *print_event_info,
     */
     if (type == binary_log::HEARTBEAT_LOG_EVENT)
       continue;
+    event_buf= (char *) net->read_pos + 1;
+    event_len= len - 1;
+    if (rewrite_db_filter(&event_buf, &event_len, glob_description_event))
+    {
+      error("Got a fatal error while applying rewrite db filter.");
+      DBUG_RETURN(ERROR_STOP);
+    }
 
     if (!raw_mode || (type == binary_log::ROTATE_EVENT) ||
         (type == binary_log::FORMAT_DESCRIPTION_EVENT))
     {
-      if (!(ev= Log_event::read_log_event((const char*) net->read_pos + 1 ,
-                                          len - 1, &error_msg,
+      if (!(ev= Log_event::read_log_event((const char*) event_buf,
+                                          event_len, &error_msg,
                                           glob_description_event,
                                           opt_verify_binlog_checksum)))
       {

mysql-test/suite/binlog/r/binlog_mysqlbinlog_rewrite_db.result

@@ -10,6 +10,9 @@ DELETE FROM t1 WHERE i=2;
 [Syntax error in the use of the new option: The '->' is missing]
 [Syntax error in the use of the new option: The to database name is missing]
 [VALID SYNTAX,The from->to database names is correctly mentioned]
+[VALID SYNTAX read from remote server ,The from->to database names are correctly mentioned]
+[VALID SYNTAX, but during the application of rewrite_db filter an invalid event is found. Hence mysqlbinlog tool should exit with an appropriate error]
+[ERROR: Got fatal error while applying rewrite db filter.]
 #Dropping the database db1 and creating the table in the new database db2.
 CREATE DATABASE db2;
 DROP DATABASE db1;
@@ -20,6 +23,12 @@ DROP DATABASE db1;
 RESET MASTER;
 [The event of table db1.t1 has been successfully applied to db2.t1]
 include/assert.inc [Assert that table db2.t1 has one row after applying the sql file.]
+DROP DATABASE db1;
+DROP DATABASE db2;
+CREATE DATABASE db2;
+RESET MASTER;
+[The event of table db1.t1 has been successfully applied to db2.t1]
+include/assert.inc [Assert that table db2.t1 has one row after applying the sql file.]
 CLEANUP
 DROP DATABASE db1;
 DROP DATABASE db2;

mysql-test/suite/binlog/t/binlog_mysqlbinlog_rewrite_db.test

@@ -9,6 +9,25 @@
 # 2. Apply the new binlog file ( with database rewritten ) to a new database
 #    and check if it works.
 #
+# Bug26117735: MYSQLBINLOG READ-FROM-REMOTE-SERVER NOT HONORING REWRITE_DB
+# FILTERING
+#
+# Problem:
+# When running mysqlbinlog with the --read-from-remote-server option,
+# the processing of the binlog entries accepts rewrite_db as an argument, but
+# ignores the rewrite rule.  Therefore no filtering is done on the binlog
+# entries, resulting in failures to write data in the target DB.
+#
+# Test case1:
+# Verify that rewrite_db filter works fine when reading binary log from remote
+# server.
+#
+# Test case2:
+# Verify that error scenario is handled properly in a case where rewrite_db
+# filter fails to rewrite the databases.
+#
+# mysqlbinlog should be debug compiled.
+--source include/mysqlbinlog_have_debug.inc
 --source include/have_binlog_format_row.inc
 
 RESET MASTER;
@@ -42,6 +61,17 @@ DELETE FROM t1 WHERE i=2;
 --echo [VALID SYNTAX,The from->to database names is correctly mentioned]
 --exec $MYSQL_BINLOG --force-if-open --rewrite-db="db1->db2" $MYSQLD_DATADIR/master-bin.000001 > $MYSQLTEST_VARDIR/tmp/row_event_rewrite.sql
 
+--let $binlog_file= query_get_value(SHOW MASTER STATUS, File, 1)
+
+# Bug26117735: MYSQLBINLOG READ-FROM-REMOTE-SERVER NOT HONORING REWRITE_DB FILTERING
+--echo [VALID SYNTAX read from remote server ,The from->to database names are correctly mentioned]
+--exec $MYSQL_BINLOG --force-if-open --read-from-remote-server --user=root --host=127.0.0.1 --port=$MASTER_MYPORT --rewrite-db="db1->db2" $binlog_file > $MYSQLTEST_VARDIR/tmp/row_event_from_remote_server_rewrite.sql
+
+--echo [VALID SYNTAX, but during the application of rewrite_db filter an invalid event is found. Hence mysqlbinlog tool should exit with an appropriate error]
+--echo [ERROR: Got fatal error while applying rewrite db filter.]
+--error 1
+--exec $MYSQL_BINLOG --force-if-open -#d,'simulate_corrupt_event_len' --read-from-remote-server --user=root --host=127.0.0.1 --port=$MASTER_MYPORT --rewrite-db="db1->db2" $binlog_file > $MYSQLTEST_VARDIR/tmp/tmp.sql
+
 --echo #Dropping the database db1 and creating the table in the new database db2.
 
 CREATE DATABASE db2;
@@ -69,9 +99,23 @@ RESET MASTER;
 --let $assert_cond= `SELECT COUNT(*)=1 from db2.t1`
 --source include/assert.inc
 
+DROP DATABASE db1;
+DROP DATABASE db2;
+CREATE DATABASE db2;
+# With gtid-mode=on we need purge gtid_executed, if not transactions
+# replayed through mysqlbinlog will be skipped.
+RESET MASTER;
+--echo [The event of table db1.t1 has been successfully applied to db2.t1]
+--exec $MYSQL  --database=db2 --local-infile=1 < $MYSQLTEST_VARDIR/tmp/row_event_from_remote_server_rewrite.sql
+--let $assert_text= Assert that table db2.t1 has one row after applying the sql file.
+--let $assert_cond= `SELECT COUNT(*)=1 from db2.t1`
+--source include/assert.inc
+
 --echo CLEANUP
 
 --remove_file $MYSQLTEST_VARDIR/tmp/row_event.sql
 --remove_file $MYSQLTEST_VARDIR/tmp/row_event_rewrite.sql
+--remove_file $MYSQLTEST_VARDIR/tmp/row_event_from_remote_server_rewrite.sql
+--remove_file $MYSQLTEST_VARDIR/tmp/tmp.sql
 DROP DATABASE db1;
 DROP DATABASE db2;