Use larger buffer when reading binary and relay logs

- Should speed up replication

sql/log.cc

@@ -2828,7 +2828,9 @@ bool MYSQL_LOG::open(
   else if ((seek_offset= mysql_file_tell(file, MYF(MY_WME))))
     goto err;
 
-  if (init_io_cache(&log_file, file, IO_SIZE, io_cache_type, seek_offset, 0,
+  if (init_io_cache(&log_file, file, (log_type == LOG_NORMAL ? IO_SIZE :
+                                      LOG_BIN_IO_SIZE),
+                    io_cache_type, seek_offset, 0,
                     MYF(MY_WME | MY_NABP |
                         ((log_type == LOG_BIN) ? MY_WAIT_IF_FULL : 0))))
     goto err;

sql/log.h

@@ -294,6 +294,12 @@ class Rows_log_event;
 enum enum_log_type { LOG_UNKNOWN, LOG_NORMAL, LOG_BIN };
 enum enum_log_state { LOG_OPENED, LOG_CLOSED, LOG_TO_BE_OPENED };
 
+/*
+  Use larger buffers when reading from and to binary log
+  We make it one step smaller than 64K to account for malloc overhead.
+*/
+#define LOG_BIN_IO_SIZE MY_ALIGN_DOWN(65536-1, IO_SIZE)
+
 /*
   TODO use mmap instead of IO_CACHE for binlog
   (mmap+fsync is two times faster than write+fsync)

sql/rpl_rli.cc

@@ -268,7 +268,7 @@ a file name for --relay-log-index option", opt_relaylog_index_name);
       msg= current_thd->get_stmt_da()->message();
       goto err;
     }
-    if (init_io_cache(&info_file, info_fd, IO_SIZE*2, READ_CACHE, 0L,0,
+    if (init_io_cache(&info_file, info_fd, LOG_BIN_IO_SIZE, READ_CACHE, 0L,0,
                       MYF(MY_WME)))
     {
       sql_print_error("Failed to create a cache on relay log info file '%s'",
@@ -303,7 +303,7 @@ Failed to open the existing relay log info file '%s' (errno %d)",
         error= 1;
       }
       else if (init_io_cache(&info_file, info_fd,
-                             IO_SIZE*2, READ_CACHE, 0L, 0, MYF(MY_WME)))
+                             LOG_BIN_IO_SIZE, READ_CACHE, 0L, 0, MYF(MY_WME)))
       {
         sql_print_error("Failed to create a cache on relay log info file '%s'",
                         fname);