Commit f8826979 authored by unknown's avatar unknown
Browse files

Avoid calls to my_seek() and my_tell() on log files so that 

non-seekable files like FIFOs can be used for logs other
than the binlog. (Bug #8271)


include/my_sys.h:
  Add APPEND_CACHE cache type
mysys/mf_iocache.c:
  Handle APPEND_CACHE cache type to avoid calling my_seek() and my_tell()
  on logs opened O_APPEND that we never read from (so they can be a
  non-seekable file like a FIFO).
sql/mysqld.cc:
  Use APPEND_CACHE for log files not set to SEQ_READ_APPEND.
parent fd4b5c8d

include/my_sys.h

+1 −0
Original line number Diff line number Diff line
@@ -270,6 +270,7 @@ enum loglevel { 
enum cache_type

{

  READ_CACHE,WRITE_CACHE,

  APPEND_CACHE,                 /* Like WRITE_CACHE, but only append */

  SEQ_READ_APPEND		/* sequential read or append */,

  READ_FIFO, READ_NET,WRITE_NET};

mysys/mf_iocache.c

+12 −4
Original line number Diff line number Diff line
@@ -88,7 +88,7 @@ static void my_aiowait(my_aio_result *result); 
void setup_io_cache(IO_CACHE* info)

{

  /* Ensure that my_b_tell() and my_b_bytes_in_cache works */

  if (info->type == WRITE_CACHE)

  if (info->type == WRITE_CACHE || info->type == APPEND_CACHE)

  {

    info->current_pos= &info->write_pos;

    info->current_end= &info->write_end;
@@ -223,7 +223,7 @@ int init_io_cache(IO_CACHE *info, File file, uint cachesize, 
#endif

  }



  if (type == WRITE_CACHE)

  if (type == WRITE_CACHE || type == APPEND_CACHE)

    info->write_end=

      info->buffer+info->buffer_length- (seek_offset & (IO_SIZE-1));

  else
@@ -293,6 +293,7 @@ my_bool reinit_io_cache(IO_CACHE *info, enum cache_type type, 
  /* One can't do reinit with the following types */

  DBUG_ASSERT(type != READ_NET && info->type != READ_NET &&

	      type != WRITE_NET && info->type != WRITE_NET &&

	      type != APPEND_CACHE && info->type != APPEND_CACHE &&

	      type != SEQ_READ_APPEND && info->type != SEQ_READ_APPEND);



  /* If the whole file is in memory, avoid flushing to disk */
@@ -1098,7 +1099,8 @@ int my_b_flush_io_cache(IO_CACHE *info, int need_append_buffer_lock) 
  my_off_t pos_in_file;

  DBUG_ENTER("my_b_flush_io_cache");



  if (!(append_cache = (info->type == SEQ_READ_APPEND)))

  if (!(append_cache = (info->type == SEQ_READ_APPEND ||

                        info->type == APPEND_CACHE)))

    need_append_buffer_lock=0;



  if (info->type == WRITE_CACHE || append_cache)
@@ -1145,7 +1147,13 @@ int my_b_flush_io_cache(IO_CACHE *info, int need_append_buffer_lock) 
      else

      {

	info->end_of_file+=(info->write_pos-info->append_read_pos);

	DBUG_ASSERT(info->end_of_file == my_tell(info->file,MYF(0)));

        /*

          We only need to worry that info->end_of_file is really accurate

          for SEQ_READ_APPEND. For APPEND_CACHE, it is possible that the

          file is non-seekable, like a FIFO.

         */

	DBUG_ASSERT(info->type != SEQ_READ_APPEND ||

                    info->end_of_file == my_tell(info->file,MYF(0)));

      }



      info->append_read_pos=info->write_pos=info->write_buffer;

sql/mysqld.cc

+1 −1
Original line number Diff line number Diff line
@@ -2198,7 +2198,7 @@ bool open_log(MYSQL_LOG *log, const char *hostname, 
    opt_name=tmp;

  }

  return log->open(opt_name, type, 0, index_file_name,

		   (read_append) ? SEQ_READ_APPEND : WRITE_CACHE,

		   (read_append) ? SEQ_READ_APPEND : APPEND_CACHE,

		   no_auto_events, max_size);

}