Bug #18199 PURGE BINARY LOGS fails silently with missing logs;

Bug #18453  Warning/error message if there is a mismatch between ...
 
There were three problems:
 
 1. the reported lack of warnings for the BEFORE syntax of PURGE;
 2. the similar lack of warnings for the TO syntax;
 3. incompatible behaviour between the two in that the latter blanked out
    regardlessly of presence or lack the actual file corresponding to
    an index record; the former version gave up at the first mismatch.

fixed with deploying the warning's generation and synronizing logics of 
purge_logs() and purge_logs_before_date().
my_stat() is called in either of two branches of purge_logs() (responsible
for the TO syntax of PURGE) similarly to how it has behaved in the BEFORE syntax.
If there is no actual binlog file, my_stat returns NULL and my_delete is
not invoked.
A critical error is reported to the user if a file from the index
could not be retrieved info about or deleted with a system error code
different than ENOENT.

mysql-test/include/show_binary_logs.inc

+--replace_result $MYSQLTEST_VARDIR MYSQLTEST_VARDIR
+--replace_column 2 #
+show binary logs;

mysql-test/r/binlog_index.result

+flush logs;
+flush logs;
+flush logs;
+show binary logs;
+Log_name	File_size
+master-bin.000001	#
+master-bin.000002	#
+master-bin.000003	#
+master-bin.000004	#
+purge binary logs TO 'master-bin.000004';
+Warnings:
+Warning	1476	Being purged log MYSQLTEST_VARDIR/log/master-bin.000001 was not found
+*** must show a list starting from the 'TO' argument of PURGE ***
+show binary logs;
+Log_name	File_size
+master-bin.000004	#
+reset master;
+flush logs;
+flush logs;
+flush logs;
+*** must be a warning master-bin.000001 was not found ***
+Warnings:
+Warning	1476	Being purged log MYSQLTEST_VARDIR/log/master-bin.000001 was not found
+*** must show one record, of the active binlog, left in the index file after PURGE ***
+show binary logs;
+Log_name	File_size
+master-bin.000004	#
+reset master;
+flush logs;
+flush logs;
+flush logs;
+purge binary logs TO 'master-bin.000002';
+ERROR HY000: Fatal error during log purge
+show warnings;
+Level	Code	Message
+Error	1377	a problem with deleting MYSQLTEST_VARDIR/log/master-bin.000001; consider examining correspondence of your binlog index file to the actual binlog files
+Error	1377	Fatal error during log purge
+reset master;
+End of tests

mysql-test/t/binlog_index.test

+#
+# testing of purging of binary log files bug#18199/Bug#18453
+#
+source include/have_log_bin.inc;
+source include/not_embedded.inc;
+
+#
+# testing purge binary logs TO
+#
+
+flush logs;
+flush logs;
+flush logs;
+
+source include/show_binary_logs.inc;
+
+remove_file $MYSQLTEST_VARDIR/log/master-bin.000001;
+
+# there must be a warning with file names
+--replace_result $MYSQLTEST_VARDIR MYSQLTEST_VARDIR
+purge binary logs TO 'master-bin.000004';
+
+--echo *** must show a list starting from the 'TO' argument of PURGE ***
+source include/show_binary_logs.inc;
+
+#
+# testing purge binary logs BEFORE
+#
+
+reset master;
+
+flush logs;
+flush logs;
+flush logs;
+remove_file $MYSQLTEST_VARDIR/log/master-bin.000001;
+
+--echo *** must be a warning master-bin.000001 was not found ***
+let $date=`select NOW()  +  INTERVAL 1 MINUTE`;
+--disable_query_log
+--replace_result $MYSQLTEST_VARDIR MYSQLTEST_VARDIR
+eval purge binary logs BEFORE '$date';
+--enable_query_log
+
+--echo *** must show one record, of the active binlog, left in the index file after PURGE ***
+source include/show_binary_logs.inc;
+
+#
+# testing a fatal error
+# Turning a binlog file into a directory must be a portable setup
+# 
+
+reset master;
+
+flush logs;
+flush logs;
+flush logs;
+
+remove_file $MYSQLTEST_VARDIR/log/master-bin.000001;
+mkdir $MYSQLTEST_VARDIR/log/master-bin.000001;
+
+--error ER_BINLOG_PURGE_FATAL_ERR
+purge binary logs TO 'master-bin.000002';
+--replace_result $MYSQLTEST_VARDIR MYSQLTEST_VARDIR
+show warnings;
+rmdir $MYSQLTEST_VARDIR/log/master-bin.000001;
+--disable_warnings
+reset master;
+--enable_warnings
+--echo End of tests

sql/log.cc

@@ -1180,6 +1180,8 @@ int MYSQL_LOG::update_log_index(LOG_INFO* log_info, bool need_update_threads)
   RETURN VALUES
     0				ok
     LOG_INFO_EOF		to_log not found
+    LOG_INFO_FATAL              if any other than ENOENT error from
+                                my_stat() or my_delete()
 */
 
 int MYSQL_LOG::purge_logs(const char *to_log, 
@@ -1208,33 +1210,75 @@ int MYSQL_LOG::purge_logs(const char *to_log,
   while ((strcmp(to_log,log_info.log_file_name) || (exit_loop=included)) &&
          !log_in_use(log_info.log_file_name))
   {
-    ulong file_size= 0;
-    if (decrease_log_space) //stat the file we want to delete
+    MY_STAT s;
+    if (!my_stat(log_info.log_file_name, &s, MYF(0)))
     {
-      MY_STAT s;
-
-      /* 
-         If we could not stat, we can't know the amount
-         of space that deletion will free. In most cases,
-         deletion won't work either, so it's not a problem.
-      */
-      if (my_stat(log_info.log_file_name,&s,MYF(0)))
-        file_size= s.st_size;
-      else
-	sql_print_information("Failed to execute my_stat on file '%s'",
+      if (my_errno == ENOENT) 
+      {
+        /*
+          It's not fatal if we can't stat a log file that does not exist;
+          If we could not stat, we won't delete.
+        */     
+        push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                            ER_LOG_PURGE_NO_FILE, ER(ER_LOG_PURGE_NO_FILE),
+                            log_info.log_file_name);
+        sql_print_information("Failed to execute my_stat on file '%s'",
 			      log_info.log_file_name);
+        my_errno= 0;
+      }
+      else
+      {
+        /*
+          Other than ENOENT are fatal
+        */
+        push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_ERROR,
+                            ER_BINLOG_PURGE_FATAL_ERR,
+                            "a problem with getting info on being purged %s; "
+                            "consider examining correspondence "
+                            "of your binlog index file "
+                            "to the actual binlog files",
+                            log_info.log_file_name);
+        error= LOG_INFO_FATAL;
+        goto err;
+      }
+    }
+    else
+    {
+      DBUG_PRINT("info",("purging %s",log_info.log_file_name));
+      if (!my_delete(log_info.log_file_name, MYF(0)))
+      {
+        if (decrease_log_space)
+          *decrease_log_space-= s.st_size;
+      }
+      else
+      {
+        if (my_errno == ENOENT) 
+        {
+          push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                              ER_LOG_PURGE_NO_FILE, ER(ER_LOG_PURGE_NO_FILE),
+                              log_info.log_file_name);
+          sql_print_information("Failed to delete file '%s'",
+                                log_info.log_file_name);
+          my_errno= 0;
+        }
+        else
+        {
+          push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_ERROR,
+                              ER_BINLOG_PURGE_FATAL_ERR,
+                              "a problem with deleting %s; "
+                              "consider examining correspondence "
+                              "of your binlog index file "
+                              "to the actual binlog files",
+                              log_info.log_file_name);
+          error= LOG_INFO_FATAL;
+          goto err;
+        }
+      }
     }
-    /*
-      It's not fatal if we can't delete a log file ;
-      if we could delete it, take its size into account
-    */
-    DBUG_PRINT("info",("purging %s",log_info.log_file_name));
-    if (!my_delete(log_info.log_file_name, MYF(0)) && decrease_log_space)
-      *decrease_log_space-= file_size;
     if (find_next_log(&log_info, 0) || exit_loop)
       break;
   }
-
+  
   /*
     If we get killed -9 here, the sysadmin would have to edit
     the log index file after restart - otherwise, this should be safe
@@ -1263,6 +1307,8 @@ err:
   RETURN VALUES
     0				ok
     LOG_INFO_PURGE_NO_ROTATE	Binary file that can't be rotated
+    LOG_INFO_FATAL              if any other than ENOENT error from
+                                my_stat() or my_delete()
 */
 
 int MYSQL_LOG::purge_logs_before_date(time_t purge_time)
@@ -1286,11 +1332,66 @@ int MYSQL_LOG::purge_logs_before_date(time_t purge_time)
   while (strcmp(log_file_name, log_info.log_file_name) &&
 	 !log_in_use(log_info.log_file_name))
   {
-    /* It's not fatal even if we can't delete a log file */
-    if (!my_stat(log_info.log_file_name, &stat_area, MYF(0)) ||
-	stat_area.st_mtime >= purge_time)
-      break;
-    my_delete(log_info.log_file_name, MYF(0));
+    if (!my_stat(log_info.log_file_name, &stat_area, MYF(0)))
+    {
+      if (my_errno == ENOENT) 
+      {
+        /*
+          It's not fatal if we can't stat a log file that does not exist.
+        */     
+        push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                            ER_LOG_PURGE_NO_FILE, ER(ER_LOG_PURGE_NO_FILE),
+                            log_info.log_file_name);
+	sql_print_information("Failed to execute my_stat on file '%s'",
+			      log_info.log_file_name);
+        my_errno= 0;
+      }
+      else
+      {
+        /*
+          Other than ENOENT are fatal
+        */
+        push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_ERROR,
+                            ER_BINLOG_PURGE_FATAL_ERR,
+                            "a problem with getting info on being purged %s; "
+                            "consider examining correspondence "
+                            "of your binlog index file "
+                            "to the actual binlog files",
+                            log_info.log_file_name);
+        error= LOG_INFO_FATAL;
+        goto err;
+      }
+    }
+    else
+    {
+      if (stat_area.st_mtime >= purge_time)
+        break;
+      if (my_delete(log_info.log_file_name, MYF(0)))
+      {
+        if (my_errno == ENOENT) 
+        {
+          /* It's not fatal even if we can't delete a log file */
+          push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                              ER_LOG_PURGE_NO_FILE, ER(ER_LOG_PURGE_NO_FILE),
+                              log_info.log_file_name);
+          sql_print_information("Failed to delete file '%s'",
+                                log_info.log_file_name);
+          my_errno= 0;
+        }
+        else
+        {
+          push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_ERROR,
+                              ER_BINLOG_PURGE_FATAL_ERR,
+                              "a problem with deleting %s; "
+                              "consider examining correspondence "
+                              "of your binlog index file "
+                              "to the actual binlog files",
+                              log_info.log_file_name);
+          error= LOG_INFO_FATAL;
+          goto err;
+        }
+      }
+    }
     if (find_next_log(&log_info, 0))
       break;
   }

sql/share/errmsg.txt

@@ -5641,3 +5641,5 @@ ER_NAME_BECOMES_EMPTY
         eng "Name '%-.64s' has become ''"
 ER_AMBIGUOUS_FIELD_TERM
 	eng "First character of the FIELDS TERMINATED string is ambiguous; please use non-optional and non-empty FIELDS ENCLOSED BY"
+ER_LOG_PURGE_NO_FILE  
+	eng "Being purged log %s was not found"