BUG#11760927

Automerged approved bzr bundle in latest mysql-5.5.

mysql-test/suite/rpl/r/rpl_row_find_row_debug.result

+include/master-slave.inc
+[connection master]
+include/stop_slave.inc
+SET GLOBAL log_warnings = 2;
+SET GLOBAL debug="d,inject_long_find_row_note";
+include/start_slave.inc
+CREATE TABLE t1 (c1 INT);
+INSERT INTO t1 VALUES (1), (2);
+UPDATE t1 SET c1= 1000 WHERE c1=2;
+DELETE FROM t1;
+DROP TABLE t1;
+# Check if any note related to long DELETE_ROWS and UPDATE_ROWS appears in the error log
+Occurrences: update=1, delete=1
+include/stop_slave.inc
+SET GLOBAL debug = '';
+SET GLOBAL log_warnings = 1;
+include/start_slave.inc
+include/rpl_end.inc

mysql-test/suite/rpl/t/rpl_row_find_row_debug.test

+#
+# Bug#11760927: 53375: RBR + NO PK => HIGH LOAD ON SLAVE (TABLE SCAN/CPU) => SLAVE FAILURE
+#
+--source include/master-slave.inc
+--source include/have_binlog_format_row.inc
+--source include/have_debug.inc
+
+# SETUP
+# - setup log_warnings and debug 
+--connection slave
+--source include/stop_slave.inc
+--let $debug_save= `SELECT @@GLOBAL.debug`
+--let $log_warnings_save= `SELECT @@GLOBAL.log_warnings`
+
+SET GLOBAL log_warnings = 2;
+
+let $log_error_= `SELECT @@GLOBAL.log_error`;
+if(!$log_error_)
+{
+    # MySQL Server on windows is started with --console and thus
+    # does not know the location of its .err log, use default location
+    let $log_error_ = $MYSQLTEST_VARDIR/log/mysqld.2.err;
+}
+
+# Assign env variable LOG_ERROR
+let LOG_ERROR=$log_error_;
+
+# force printing the notes to the error log
+SET GLOBAL debug="d,inject_long_find_row_note";
+--source include/start_slave.inc
+
+# test
+--connection master
+CREATE TABLE t1 (c1 INT);
+--sync_slave_with_master
+--connection master
+
+INSERT INTO t1 VALUES (1), (2);
+UPDATE t1 SET c1= 1000 WHERE c1=2;
+DELETE FROM t1;
+DROP TABLE t1;
+--sync_slave_with_master
+
+--echo # Check if any note related to long DELETE_ROWS and UPDATE_ROWS appears in the error log
+perl;
+  use strict;
+  my $log_error= $ENV{'LOG_ERROR'} or die "LOG_ERROR not set";
+  open(FILE, "$log_error") or die("Unable to open $log_error: $!\n");
+  my $upd_count = () = grep(/The slave is applying a ROW event on behalf of an UPDATE statement on table t1 and is currently taking a considerable amount/g,<FILE>);
+  seek(FILE, 0, 0) or die "Can't seek to beginning of file: $!";
+  my $del_count = () = grep(/The slave is applying a ROW event on behalf of a DELETE statement on table t1 and is currently taking a considerable amount/g,<FILE>);
+  print "Occurrences: update=$upd_count, delete=$del_count\n";
+  close(FILE);
+EOF
+
+# cleanup
+--source include/stop_slave.inc
+--eval SET GLOBAL debug = '$debug_save'
+--eval SET GLOBAL log_warnings = $log_warnings_save
+--source include/start_slave.inc
+
+--source include/rpl_end.inc

sql/log_event.cc

@@ -7761,6 +7761,12 @@ int Rows_log_event::do_apply_event(Relay_log_info const *rli)
 
     // row processing loop
 
+    /* 
+      set the initial time of this ROWS statement if it was not done
+      before in some other ROWS event. 
+     */
+    const_cast<Relay_log_info*>(rli)->set_row_stmt_start_timestamp();
+
     while (error == 0 && m_curr_row < m_rows_end)
     {
       /* in_use can have been set to NULL in close_tables_for_reopen */
@@ -9252,6 +9258,51 @@ static bool record_compare(TABLE *table)
   return result;
 }
 
+/* 
+  Check if we are already spending too much time on this statement.
+  if we are, warn user that it might be because table does not have
+  a PK, but only if the warning was not printed before for this STMT.
+
+  @param type          The event type code.
+  @param table_name    The name of the table that the slave is 
+                       operating.
+  @param is_index_scan States whether the slave is doing an index scan 
+                       or not.
+  @param rli           The relay metadata info.
+*/
+static inline 
+void issue_long_find_row_warning(Log_event_type type, 
+                                 const char *table_name,
+                                 bool is_index_scan,
+                                 const Relay_log_info *rli)
+{
+  if ((global_system_variables.log_warnings > 1 && 
+      !const_cast<Relay_log_info*>(rli)->is_long_find_row_note_printed()))
+  {
+    time_t now= my_time(0);
+    time_t stmt_ts= const_cast<Relay_log_info*>(rli)->get_row_stmt_start_timestamp();
+    
+    DBUG_EXECUTE_IF("inject_long_find_row_note", 
+                    stmt_ts-=(LONG_FIND_ROW_THRESHOLD*2););
+
+    time_t delta= (now - stmt_ts);
+
+    if (delta > LONG_FIND_ROW_THRESHOLD)
+    {
+      const_cast<Relay_log_info*>(rli)->set_long_find_row_note_printed();
+      const char* evt_type= type == DELETE_ROWS_EVENT ? " DELETE" : "n UPDATE";
+      const char* scan_type= is_index_scan ? "scanning an index" : "scanning the table";
+
+      sql_print_information("The slave is applying a ROW event on behalf of a%s statement "
+                            "on table %s and is currently taking a considerable amount "
+                            "of time (%lu seconds). This is due to the fact that it is %s "
+                            "while looking up records to be processed. Consider adding a "
+                            "primary key (or unique key) to the table to improve "
+                            "performance.", evt_type, table_name, delta, scan_type);
+    }
+  }
+}
+
 /**
   Locate the current row in event's table.
 
@@ -9287,6 +9338,7 @@ int Rows_log_event::find_row(const Relay_log_info *rli)
 
   TABLE *table= m_table;
   int error= 0;
+  bool is_table_scan= false, is_index_scan= false;
 
   /*
     rpl_row_tabledefs.test specifies that
@@ -9452,6 +9504,8 @@ int Rows_log_event::find_row(const Relay_log_info *rli)
       }
     }
 
+    is_index_scan=true;
+
     /*
       In case key is not unique, we still have to iterate over records found
       and find the one which is identical to the row given. A copy of the 
@@ -9508,6 +9562,8 @@ int Rows_log_event::find_row(const Relay_log_info *rli)
       goto err;
     }
 
+    is_table_scan= true;
+
     /* Continue until we find the right record or have made a full loop */
     do
     {
@@ -9561,10 +9617,18 @@ int Rows_log_event::find_row(const Relay_log_info *rli)
     goto err;
   }
 ok:
+  if (is_table_scan || is_index_scan)
+    issue_long_find_row_warning(get_type_code(), m_table->alias, 
+                                is_index_scan, rli);
+
   table->default_column_bitmaps();
   DBUG_RETURN(0);
 
 err:
+  if (is_table_scan || is_index_scan)
+    issue_long_find_row_warning(get_type_code(), m_table->alias, 
+                                is_index_scan, rli);
+
   table->default_column_bitmaps();
   DBUG_RETURN(error);
 }

sql/log_event.h

@@ -53,6 +53,7 @@
 class String;
 
 #define PREFIX_SQL_LOAD "SQL_LOAD-"
+#define LONG_FIND_ROW_THRESHOLD 60 /* seconds */
 
 /**
    Either assert or return an error.

sql/rpl_rli.cc

@@ -1245,6 +1245,15 @@ void Relay_log_info::cleanup_context(THD *thd, bool error)
   */
   thd->variables.option_bits&= ~OPTION_NO_FOREIGN_KEY_CHECKS;
   thd->variables.option_bits&= ~OPTION_RELAXED_UNIQUE_CHECKS;
+
+  /*
+    Reset state related to long_find_row notes in the error log:
+    - timestamp
+    - flag that decides whether the slave prints or not
+  */
+  reset_row_stmt_start_timestamp();
+  unset_long_find_row_note_printed();
+
   DBUG_VOID_RETURN;
 }
 

sql/rpl_rli.h

@@ -452,8 +452,49 @@ class Relay_log_info : public Slave_reporting_capability
       (m_flags & (1UL << IN_STMT));
   }
 
+  time_t get_row_stmt_start_timestamp()
+  {
+    return row_stmt_start_timestamp;
+  }
+
+  time_t set_row_stmt_start_timestamp()
+  {
+    if (row_stmt_start_timestamp == 0)
+      row_stmt_start_timestamp= my_time(0);
+
+    return row_stmt_start_timestamp;
+  }
+
+  void reset_row_stmt_start_timestamp()
+  {
+    row_stmt_start_timestamp= 0;
+  }
+
+  void set_long_find_row_note_printed()
+  {
+    long_find_row_note_printed= true;
+  }
+
+  void unset_long_find_row_note_printed()
+  {
+    long_find_row_note_printed= false;
+  }
+
+  bool is_long_find_row_note_printed()
+  {
+    return long_find_row_note_printed;
+  }
+
 private:
+
   uint32 m_flags;
+
+  /*
+    Runtime state for printing a note when slave is taking
+    too long while processing a row event.
+   */
+  time_t row_stmt_start_timestamp;
+  bool long_find_row_note_printed;
 };