Many files:

   Added the MAX_LENGTH_FOR_SORT_DATA option
filesort.cc:
  Added the MAX_LENGTH_FOR_SORT_DATA option


sql/filesort.cc:
  Added the MAX_LENGTH_FOR_SORT_DATA option
sql/mysqld.cc:
   Added the MAX_LENGTH_FOR_SORT_DATA option
sql/opt_range.cc:
   Added the MAX_LENGTH_FOR_SORT_DATA option
sql/records.cc:
   Added the MAX_LENGTH_FOR_SORT_DATA option
sql/set_var.cc:
   Added the MAX_LENGTH_FOR_SORT_DATA option
sql/sql_base.cc:
   Added the MAX_LENGTH_FOR_SORT_DATA option
sql/sql_class.h:
   Added the MAX_LENGTH_FOR_SORT_DATA option
sql/sql_delete.cc:
   Added the MAX_LENGTH_FOR_SORT_DATA option
sql/sql_select.cc:
   Added the MAX_LENGTH_FOR_SORT_DATA option
sql/sql_sort.h:
   Added the MAX_LENGTH_FOR_SORT_DATA option
sql/sql_table.cc:
   Added the MAX_LENGTH_FOR_SORT_DATA option
sql/sql_update.cc:
   Added the MAX_LENGTH_FOR_SORT_DATA option
sql/structs.h:
   Added the MAX_LENGTH_FOR_SORT_DATA option
sql/table.h:
   Added the MAX_LENGTH_FOR_SORT_DATA option
sql/uniques.cc:
   Added the MAX_LENGTH_FOR_SORT_DATA option

sql/filesort.cc

+
 /* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB  
 
    This program is free software; you can redistribute it and/or modify
@@ -51,6 +52,10 @@ static int merge_index(SORTPARAM *param,uchar *sort_buffer,
 static bool save_index(SORTPARAM *param,uchar **sort_keys, uint count);
 static uint sortlength(SORT_FIELD *sortorder, uint s_length,
 		       bool *multi_byte_charset);
+static SORT_ADDON_FIELD *get_addon_fields(THD *thd, Field **ptabfield,
+                                          uint sortlength, uint *plength);
+static void unpack_addon_fields(struct st_sort_addon_field *addon_field,
+                                byte *buff);
 
 	/*
 	  Creates a set of pointers that can be used to read the rows
@@ -82,16 +87,48 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length,
   DBUG_PUSH("");		/* No DBUG here */
 #endif
 
-  outfile= table->io_cache;
+  outfile= table->sort.io_cache;
   my_b_clear(&tempfile);
   my_b_clear(&buffpek_pointers);
   buffpek=0;
   sort_keys= (uchar **) NULL;
   error= 1;
   bzero((char*) &param,sizeof(param));
+  param.sort_length= sortlength(sortorder, s_length, &multi_byte_charset);
   param.ref_length= table->file->ref_length;
-  param.sort_length= (sortlength(sortorder,s_length, &multi_byte_charset)+
-		      param.ref_length);
+  param.addon_field= 0;
+  param.addon_length= 0;
+  if (!(table->tmp_table || table->fulltext_searched))
+  {
+    /* 
+      Get the descriptors of all fields whose values are appended 
+      to sorted fields and get its total length in param.spack_length.
+    */
+    param.addon_field= get_addon_fields(thd, table->field, 
+                                        param.sort_length,
+                                        &param.addon_length);
+  }
+  table->sort.addon_buf= 0;
+  table->sort.addon_length= param.addon_length;
+  table->sort.addon_field= param.addon_field;
+  table->sort.unpack= unpack_addon_fields;
+  if (param.addon_field)
+  {
+    param.res_length= param.addon_length;
+    if (!(table->sort.addon_buf= (byte *) my_malloc(param.addon_length,
+                                                    MYF(MY_WME))))
+      goto err;
+  }
+  else
+  {
+    param.res_length= param.ref_length;
+    /* 
+      The reference to the record is considered 
+      as an additional sorted field
+    */
+    param.sort_length+= param.ref_length;
+  }
+  param.rec_length= param.sort_length+param.addon_length;
   param.max_rows= max_rows;
 
   if (select && select->quick)
@@ -115,7 +152,7 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length,
     records=table->file->estimate_number_of_rows();
     selected_records_file= 0;
   }
-  if (param.sort_length == param.ref_length && records > param.max_rows)
+  if (param.rec_length == param.ref_length && records > param.max_rows)
     records=param.max_rows;			/* purecov: inspected */
 
   if (multi_byte_charset &&
@@ -127,9 +164,9 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length,
   while (memavl >= min_sort_memory)
   {
     ulong old_memavl;
-    ulong keys= memavl/(param.sort_length+sizeof(char*));
+    ulong keys= memavl/(param.rec_length+sizeof(char*));
     param.keys=(uint) min(records+1, keys);
-    if ((sort_keys= (uchar **) make_char_array(param.keys, param.sort_length,
+    if ((sort_keys= (uchar **) make_char_array(param.keys, param.rec_length,
 					       MYF(0))))
       break;
     old_memavl=memavl;
@@ -176,8 +213,8 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length,
       Use also the space previously used by string pointers in sort_buffer
       for temporary key storage.
     */
-    param.keys=((param.keys*(param.sort_length+sizeof(char*))) /
-		param.sort_length-1);
+    param.keys=((param.keys*(param.rec_length+sizeof(char*))) /
+		param.rec_length-1);
     maxbuffer--;				// Offset from 0
     if (merge_many_buff(&param,(uchar*) sort_keys,buffpek,&maxbuffer,
 			&tempfile))
@@ -356,8 +393,8 @@ static ha_rows find_all_keys(SORTPARAM *param, SQL_SELECT *select,
 	if (write_keys(param,sort_keys,idx,buffpek_pointers,tempfile))
 	  DBUG_RETURN(HA_POS_ERROR);
 	idx=0;
-	if (param->ref_length == param->sort_length &&
-	    my_b_tell(tempfile)/param->sort_length >= param->max_rows)
+	if (param->ref_length == param->rec_length &&
+	    my_b_tell(tempfile)/param->rec_length >= param->max_rows)
 	{
 	  /*
 	    We are writing the result index file and have found all
@@ -385,7 +422,7 @@ static ha_rows find_all_keys(SORTPARAM *param, SQL_SELECT *select,
       write_keys(param,sort_keys,idx,buffpek_pointers,tempfile))
     DBUG_RETURN(HA_POS_ERROR);			/* purecov: inspected */
   DBUG_RETURN(my_b_inited(tempfile) ?
-	      (ha_rows) (my_b_tell(tempfile)/param->sort_length) :
+	      (ha_rows) (my_b_tell(tempfile)/param->rec_length) :
 	      idx);
 } /* find_all_keys */
 
@@ -396,27 +433,28 @@ static int
 write_keys(SORTPARAM *param, register uchar **sort_keys, uint count,
            IO_CACHE *buffpek_pointers, IO_CACHE *tempfile)
 {
-  uint sort_length;
+  uint sort_length, rec_length;
   uchar **end;
   BUFFPEK buffpek;
   DBUG_ENTER("write_keys");
 
-  sort_length=param->sort_length;
+  sort_length= param->sort_length;
+  rec_length= param->rec_length;
 #ifdef MC68000
   quicksort(sort_keys,count,sort_length);
 #else
-  my_string_ptr_sort((gptr) sort_keys,(uint) count,sort_length);
+  my_string_ptr_sort((gptr) sort_keys, (uint) count, sort_length);
 #endif
   if (!my_b_inited(tempfile) &&
-      open_cached_file(tempfile,mysql_tmpdir,TEMP_PREFIX,DISK_BUFFER_SIZE,
+      open_cached_file(tempfile, mysql_tmpdir, TEMP_PREFIX, DISK_BUFFER_SIZE,
                        MYF(MY_WME)))
     goto err;                                        /* purecov: inspected */
-  buffpek.file_pos=my_b_tell(tempfile);
+  buffpek.file_pos= my_b_tell(tempfile);
   if ((ha_rows) count > param->max_rows)
     count=(uint) param->max_rows;                /* purecov: inspected */
   buffpek.count=(ha_rows) count;
   for (end=sort_keys+count ; sort_keys != end ; sort_keys++)
-    if (my_b_write(tempfile,(byte*) *sort_keys,(uint) sort_length))
+    if (my_b_write(tempfile, (byte*) *sort_keys, (uint) rec_length))
       goto err;
   if (my_b_write(buffpek_pointers, (byte*) &buffpek, sizeof(buffpek)))
     goto err;
@@ -577,29 +615,56 @@ static void make_sortkey(register SORTPARAM *param,
     else
       to+= sort_field->length;
   }
-  memcpy((byte*) to,ref_pos,(size_s) param->ref_length);/* Save filepos last */
+
+  if (param->addon_field)
+  {
+    /* 
+      Save field values appended to sorted fields.
+      First null bit indicators are appended then field values follow.
+      In this implementation we use fixed layout for field values -
+      the same for all records.
+    */
+    SORT_ADDON_FIELD *addonf= param->addon_field;
+    uchar *nulls= to;
+    DBUG_ASSERT(addonf);
+    bzero((char *) nulls, addonf->offset);
+    to+= addonf->offset;
+    for ( ; (field= addonf->field) ; addonf++)
+    {
+      if (addonf->null_bit && field->is_null())
+        nulls[addonf->null_offset]|= addonf->null_bit;
+      else
+        field->pack((char *) to, field->ptr);
+      to+= addonf->length;
+    }
+  }
+  else
+  {
+    /* Save filepos last */
+    memcpy((byte*) to, ref_pos, (size_s) param->ref_length);
+  }
   return;
 }
 
 
 static bool save_index(SORTPARAM *param, uchar **sort_keys, uint count)
 {
-  uint offset,ref_length;
+  uint offset,res_length;
   byte *to;
   DBUG_ENTER("save_index");
 
-  my_string_ptr_sort((gptr) sort_keys,(uint) count,param->sort_length);
-  ref_length=param->ref_length;
-  offset=param->sort_length-ref_length;
+  my_string_ptr_sort((gptr) sort_keys, (uint) count, param->sort_length);
+  res_length= param->res_length;
+  offset= param->rec_length-res_length;
   if ((ha_rows) count > param->max_rows)
     count=(uint) param->max_rows;
-  if (!(to=param->sort_form->record_pointers=
-	(byte*) my_malloc(ref_length*count,MYF(MY_WME))))
+  if (!(to= param->sort_form->sort.record_pointers=
+        (byte*) my_malloc(res_length*count, MYF(MY_WME))))
     DBUG_RETURN(1);                 /* purecov: inspected */
-  for (uchar **end=sort_keys+count ; sort_keys != end ; sort_keys++)
+  for (uchar **end= sort_keys+count ; sort_keys != end ; sort_keys++)
   {
-    memcpy(to,*sort_keys+offset,ref_length);
-    to+=ref_length;
+    memcpy(to, *sort_keys+offset, res_length);
+    to+= res_length;
   }
   DBUG_RETURN(0);
 }
@@ -654,7 +719,7 @@ int merge_many_buff(SORTPARAM *param, uchar *sort_buffer,
 	/* This returns (uint) -1 if something goes wrong */
 
 uint read_to_buffer(IO_CACHE *fromfile, BUFFPEK *buffpek,
-		    uint sort_length)
+		    uint rec_length)
 {
   register uint count;
   uint length;
@@ -662,18 +727,20 @@ uint read_to_buffer(IO_CACHE *fromfile, BUFFPEK *buffpek,
   if ((count=(uint) min((ha_rows) buffpek->max_keys,buffpek->count)))
   {
     if (my_pread(fromfile->file,(byte*) buffpek->base,
-		 (length= sort_length*count),buffpek->file_pos,MYF_RW))
+		 (length= rec_length*count),buffpek->file_pos,MYF_RW))
       return((uint) -1);			/* purecov: inspected */
     buffpek->key=buffpek->base;
     buffpek->file_pos+= length;			/* New filepos */
     buffpek->count-=	count;
     buffpek->mem_count= count;
   }
-  return (count*sort_length);
+  return (count*rec_length);
 } /* read_to_buffer */
 
 
-	/* Merge buffers to one buffer */
+/* 
+   Merge buffers to one buffer 
+*/
 
 int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
                   IO_CACHE *to_file, uchar *sort_buffer,
@@ -681,7 +748,7 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
                   int flag)
 {
   int error;
-  uint sort_length,offset;
+  uint rec_length,sort_length,res_length,offset;
   ulong maxcount;
   ha_rows max_rows,org_max_rows;
   my_off_t to_start_filepos;
@@ -697,29 +764,32 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
   if (param->not_killable)
   {
     killed= &not_killable;
-    not_killable=0;
+    not_killable= 0;
   }
 
   error=0;
-  offset=(sort_length=param->sort_length)-param->ref_length;
-  maxcount=(ulong) (param->keys/((uint) (Tb-Fb) +1));
-  to_start_filepos=my_b_tell(to_file);
-  strpos=(uchar*) sort_buffer;
-  org_max_rows=max_rows=param->max_rows;
-
-  if (init_queue(&queue,(uint) (Tb-Fb)+1,offsetof(BUFFPEK,key),0,
-		 (queue_compare)
-		 (cmp=get_ptr_compare(sort_length)),(void*) &sort_length))
+  rec_length= param->rec_length;
+  res_length= param->res_length;
+  sort_length= param->sort_length;
+  offset= rec_length-res_length;
+  maxcount= (ulong) (param->keys/((uint) (Tb-Fb) +1));
+  to_start_filepos= my_b_tell(to_file);
+  strpos= (uchar*) sort_buffer;
+  org_max_rows=max_rows= param->max_rows;
+
+  if (init_queue(&queue, (uint) (Tb-Fb)+1, offsetof(BUFFPEK,key), 0,
+                 (queue_compare) (cmp= get_ptr_compare(sort_length)),
+                 (void*) &sort_length))
     DBUG_RETURN(1);                                /* purecov: inspected */
   for (buffpek= Fb ; buffpek <= Tb ; buffpek++)
   {
     buffpek->base= strpos;
-    buffpek->max_keys=maxcount;
-    strpos+= (uint) (error=(int) read_to_buffer(from_file,buffpek,
-						sort_length));
+    buffpek->max_keys= maxcount;
+    strpos+= (uint) (error= (int) read_to_buffer(from_file, buffpek,
+                                                                         rec_length));
     if (error == -1)
       goto err;                                        /* purecov: inspected */
-    queue_insert(&queue,(byte*) buffpek);
+    queue_insert(&queue, (byte*) buffpek);
   }
 
   if (param->unique_buff)
@@ -732,66 +802,69 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
        This is safe as we know that there is always more than one element
        in each block to merge (This is guaranteed by the Unique:: algorithm
     */
-    buffpek=(BUFFPEK*) queue_top(&queue);
-    memcpy(param->unique_buff, buffpek->key, sort_length);
-    if (my_b_write(to_file,(byte*) buffpek->key, sort_length))
+    buffpek= (BUFFPEK*) queue_top(&queue);
+    memcpy(param->unique_buff, buffpek->key, rec_length);
+    if (my_b_write(to_file, (byte*) buffpek->key, rec_length))
     {
       error=1; goto err;                        /* purecov: inspected */
     }
-    buffpek->key+=sort_length;
+    buffpek->key+= rec_length;
     buffpek->mem_count--;
     if (!--max_rows)
     {
-      error=0;					/* purecov: inspected */
+      error= 0;                                       /* purecov: inspected */
       goto end;                                       /* purecov: inspected */
     }
     queue_replaced(&queue);                        // Top element has been used
   }
   else
-    cmp=0;					// Not unique
+    cmp= 0;                                        // Not unique
 
   while (queue.elements > 1)
   {
     if (*killed)
     {
-      error=1; goto err;                        /* purecov: inspected */
+      error= 1; goto err;                        /* purecov: inspected */
     }
     for (;;)
     {
-      buffpek=(BUFFPEK*) queue_top(&queue);
+      buffpek= (BUFFPEK*) queue_top(&queue);
       if (cmp)                                        // Remove duplicates
       {
         if (!(*cmp)(&sort_length, &(param->unique_buff),
                     (uchar**) &buffpek->key))
               goto skip_duplicate;
-	memcpy(param->unique_buff, (uchar*) buffpek->key,sort_length);
+            memcpy(param->unique_buff, (uchar*) buffpek->key, rec_length);
       }
       if (flag == 0)
       {
-	if (my_b_write(to_file,(byte*) buffpek->key, sort_length))
+        if (my_b_write(to_file,(byte*) buffpek->key, rec_length))
         {
           error=1; goto err;                        /* purecov: inspected */
         }
       }
       else
       {
-	WRITE_REF(to_file,(byte*) buffpek->key+offset);
+        if (my_b_write(to_file, (byte*) buffpek->key+offset, res_length))
+        {
+          error=1; goto err;                        /* purecov: inspected */
+        }
       }
       if (!--max_rows)
       {
-	error=0;				/* purecov: inspected */
+        error= 0;                               /* purecov: inspected */
         goto end;                               /* purecov: inspected */
       }
 
     skip_duplicate:
-      buffpek->key+=sort_length;
+      buffpek->key+= rec_length;
       if (! --buffpek->mem_count)
       {
-	if (!(error=(int) read_to_buffer(from_file,buffpek,
-					 sort_length)))
+        if (!(error= (int) read_to_buffer(from_file,buffpek,
+                                          rec_length)))
         {
-	  uchar *base=buffpek->base;
-	  ulong max_keys=buffpek->max_keys;
+          uchar *base= buffpek->base;
+          ulong max_keys= buffpek->max_keys;
 
           VOID(queue_remove(&queue,0));
 
@@ -801,15 +874,15 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
                refpek++)
           {
             buffpek= *refpek;
-	    if (buffpek->base+buffpek->max_keys*sort_length == base)
+            if (buffpek->base+buffpek->max_keys*rec_length == base)
             {
-	      buffpek->max_keys+=max_keys;
+              buffpek->max_keys+= max_keys;
               break;
             }
-	    else if (base+max_keys*sort_length == buffpek->base)
+            else if (base+max_keys*rec_length == buffpek->base)
             {
-	      buffpek->base=base;
-	      buffpek->max_keys+=max_keys;
+              buffpek->base= base;
+              buffpek->max_keys+= max_keys;
               break;
             }
           }
@@ -821,9 +894,9 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
       queue_replaced(&queue);              /* Top element has been replaced */
     }
   }
-  buffpek=(BUFFPEK*) queue_top(&queue);
+  buffpek= (BUFFPEK*) queue_top(&queue);
   buffpek->base= sort_buffer;
-  buffpek->max_keys=param->keys;
+  buffpek->max_keys= param->keys;
 
   /*
     As we know all entries in the buffer are unique, we only have to
@@ -833,7 +906,7 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
   {
     if (!(*cmp)(&sort_length, &(param->unique_buff), (uchar**) &buffpek->key))
     {
-      buffpek->key+=sort_length;	// Remove duplicate
+      buffpek->key+= rec_length;         // Remove duplicate
       --buffpek->mem_count;
     }
   }
@@ -842,36 +915,39 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
   {
     if ((ha_rows) buffpek->mem_count > max_rows)
     {                                        /* Don't write too many records */
-      buffpek->mem_count=(uint) max_rows;
-      buffpek->count=0;			/* Don't read more */
+      buffpek->mem_count= (uint) max_rows;
+      buffpek->count= 0;                        /* Don't read more */
     }
-    max_rows-=buffpek->mem_count;
+    max_rows-= buffpek->mem_count;
     if (flag == 0)
     {
       if (my_b_write(to_file,(byte*) buffpek->key,
-		     (sort_length*buffpek->mem_count)))
+                     (rec_length*buffpek->mem_count)))
       {
-	error=1; goto err;			/* purecov: inspected */
+        error= 1; goto err;                        /* purecov: inspected */
       }
     }
     else
     {
       register uchar *end;
       strpos= buffpek->key+offset;
-      for (end=strpos+buffpek->mem_count*sort_length;
+      for (end= strpos+buffpek->mem_count*rec_length ;
            strpos != end ;
-	   strpos+=sort_length)
+           strpos+= rec_length)
+      {     
+        if (my_b_write(to_file, (byte *) strpos, res_length))
         {
-	WRITE_REF(to_file,strpos);
+          error=1; goto err;                        
         }
       }
     }
-  while ((error=(int) read_to_buffer(from_file,buffpek,sort_length))
+  }
+  while ((error=(int) read_to_buffer(from_file,buffpek, rec_length))
          != -1 && error != 0);
 
 end:
-  lastbuff->count=min(org_max_rows-max_rows,param->max_rows);
-  lastbuff->file_pos=to_start_filepos;
+  lastbuff->count= min(org_max_rows-max_rows, param->max_rows);
+  lastbuff->file_pos= to_start_filepos;
 err:
   delete_queue(&queue);
   DBUG_RETURN(error);
@@ -925,7 +1001,6 @@ sortlength(SORT_FIELD *sortorder, uint s_length, bool *multi_byte_charset)
     sortorder->need_strxnfrm= 0;
     if (sortorder->field)
     {
-      
       if (sortorder->field->type() == FIELD_TYPE_BLOB)
 	sortorder->length= thd->variables.max_sort_length;
       else
@@ -981,6 +1056,148 @@ sortlength(SORT_FIELD *sortorder, uint s_length, bool *multi_byte_charset)
 }
 
 
+/*
+  Get descriptors of fields appended to sorted fields and
+  calculate its total length
+
+  SYNOPSIS
+    get_addon_fields()
+    thd                 Current thread
+    ptabfields          Array of references to the table fields
+    sortlength          Total length of sorted fields
+    plength    out:     Total length of appended fields
+
+  DESCRIPTION
+    The function first finds out what fields are used in the result set.
+    Then it calculates the length of the buffer to store the values of
+    these fields together with the value of sort values. 
+    If the calculated length is not greater than max_length_for_sort_data
+    the function allocates memory for an array of descriptors containing
+    layouts for the values of the non-sorted fields in the buffer and
+    fills them.
+
+  NOTES
+    The null bits for the appended values are supposed to be put together
+    and stored the buffer just ahead of the value of the first field.
+
+  RETURN
+    Pointer to the layout descriptors for the appended fields, if any
+    NULL - if we do not store field values with sort data.
+*/
+
+static SORT_ADDON_FIELD *
+get_addon_fields(THD *thd, Field **ptabfield, uint sortlength, uint *plength)
+{
+  Field **pfield;
+  Field *field;
+  SORT_ADDON_FIELD *addonf;
+  uint length= 0;
+  uint fields= 0;
+  uint null_fields= 0;
+
+  /* 
+     If there is a reference to a field in the query add it
+     to the the set of appended fields.
+     Note for future refinement:
+     This this a too strong condition.
+     Actually we need only the fields referred in the
+     result set. And for some of them it makes sense to use 
+     the values directly from sorted fields.
+  */
+  *plength= 0;
+  /*
+     The following statement is added to avoid sorting in alter_table.
+     The fact is the filter 'field->query_id != thd->query_id'
+     doesn't work for alter table
+  */
+  if (thd->lex.sql_command != SQLCOM_SELECT)
+    return 0;
+  for (pfield= ptabfield; (field= *pfield) ; pfield++)
+  {
+    if (field->query_id != thd->query_id)
+      continue;
+    if (field->flags & BLOB_FLAG)
+      return 0;
+    length+= field->max_packed_col_length(field->pack_length());
+    if (field->maybe_null())
+      null_fields++;
+    fields++;
+  } 
+  if (!fields)
+    return 0;
+  length+= (null_fields+7)/8;
+
+  if (length+sortlength > thd->variables.max_length_for_sort_data ||
+      !(addonf= (SORT_ADDON_FIELD *) my_malloc(sizeof(SORT_ADDON_FIELD)*
+                                               (fields+1), MYF(MY_WME))))
+    return 0;
+
+  *plength= length;
+  length= (null_fields+7)/8;
+  null_fields= 0;
+  for (pfield= ptabfield; (field= *pfield) ; pfield++)
+  {
+    if (field->query_id != thd->query_id)
+      continue;
+    addonf->field= field;
+    addonf->offset= length;
+    if (field->maybe_null())
+    {
+      addonf->null_offset= null_fields/8;
+      addonf->null_bit= 1<<(null_fields & 7);
+      null_fields++;
+    }
+    else
+    {
+      addonf->null_offset= 0;
+      addonf->null_bit= 0;
+    }
+    addonf->length= field->max_packed_col_length(field->pack_length());
+    length+= addonf->length;
+    addonf++;
+  }
+  addonf->field= 0;     // Put end marker
+  
+  DBUG_PRINT("info",("addon_length: %d",length));
+  return (addonf-fields);
+}
+
+
+/*
+  Copy (unpack) values appended to sorted fields from a buffer back to 
+  their regular positions specified by the Field::ptr pointers.
+
+  SYNOPSIS
+    unpack_addon_fields()
+    addon_field     Array of descriptors for appended fields
+    buff            Buffer which to unpack the value from
+
+  NOTES
+    The function is supposed to be used only as a callback function
+    when getting field values for the sorted result set.
+
+  RETURN
+    void.
+*/
+
+static void 
+unpack_addon_fields(struct st_sort_addon_field *addon_field, byte *buff)
+{
+  Field *field;
+  SORT_ADDON_FIELD *addonf= addon_field;
+
+  for ( ; (field= addonf->field) ; addonf++)
+  {
+    if (addonf->null_bit && (addonf->null_bit & buff[addonf->null_offset]))
+    {
+      field->set_null();
+      continue;
+    }
+    field->set_notnull();
+    field->unpack(field->ptr, (char *) buff+addonf->offset);
+  }
+}
+
 /*
 ** functions to change a double or float to a sortable string
 ** The following should work for IEEE

sql/mysqld.cc

@@ -3457,7 +3457,7 @@ enum options
   OPT_MAX_BINLOG_CACHE_SIZE, OPT_MAX_BINLOG_SIZE,
   OPT_MAX_CONNECTIONS, OPT_MAX_CONNECT_ERRORS,
   OPT_MAX_DELAYED_THREADS, OPT_MAX_HEP_TABLE_SIZE,
-  OPT_MAX_JOIN_SIZE, OPT_MAX_SORT_LENGTH,
+  OPT_MAX_JOIN_SIZE, OPT_MAX_LENGTH_FOR_SORT_DATA, OPT_MAX_SORT_LENGTH,
   OPT_MAX_TMP_TABLES, OPT_MAX_USER_CONNECTIONS,
   OPT_MAX_WRITE_LOCK_COUNT, OPT_BULK_INSERT_BUFFER_SIZE,
   OPT_MAX_ERROR_COUNT, OPT_MAX_PREP_STMT,
@@ -4159,6 +4159,11 @@ struct my_option my_long_options[] =
    (gptr*) &global_system_variables.max_join_size,
    (gptr*) &max_system_variables.max_join_size, 0, GET_HA_ROWS, REQUIRED_ARG,
    ~0L, 1, ~0L, 0, 1, 0},
+   {"max_length_for_sort_data", OPT_MAX_LENGTH_FOR_SORT_DATA,
+    "Max number of bytes in sorted records",
+    (gptr*) &global_system_variables.max_length_for_sort_data,
+    (gptr*) &max_system_variables.max_length_for_sort_data, 0, GET_ULONG,
+    REQUIRED_ARG, 1024, 4, 8192*1024L, 0, 1, 0},
   {"max_prepared_statements", OPT_MAX_PREP_STMT,
    "Max number of prepared_statements for a thread",
    (gptr*) &global_system_variables.max_prep_stmt_count,

sql/opt_range.cc

@@ -349,13 +349,13 @@ SQL_SELECT *make_select(TABLE *head, table_map const_tables,
   select->head=head;
   select->cond=conds;
 
-  if (head->io_cache)
+  if (head->sort.io_cache)
   {
-    select->file= *head->io_cache;
+    select->file= *head->sort.io_cache;
     select->records=(ha_rows) (select->file.end_of_file/
 			       head->file->ref_length);
-    my_free((gptr) (head->io_cache),MYF(0));
-    head->io_cache=0;
+    my_free((gptr) (head->sort.io_cache),MYF(0));
+    head->sort.io_cache=0;
   }
   DBUG_RETURN(select);
 }

sql/records.cc

+
 /* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
 
    This program is free software; you can redistribute it and/or modify
@@ -22,6 +23,8 @@
 static int rr_quick(READ_RECORD *info);
 static int rr_sequential(READ_RECORD *info);
 static int rr_from_tempfile(READ_RECORD *info);
+static int rr_unpack_from_tempfile(READ_RECORD *info);
+static int rr_unpack_from_buffer(READ_RECORD *info);
 static int rr_from_pointers(READ_RECORD *info);
 static int rr_from_cache(READ_RECORD *info);
 static int init_rr_cache(READ_RECORD *info);
@@ -41,8 +44,16 @@ void init_read_record(READ_RECORD *info,THD *thd, TABLE *table,
   info->table=table;
   info->file= table->file;
   info->forms= &info->table;		/* Only one table */
-  info->record=table->record[0];
-  info->ref_length=table->file->ref_length;
+  if (table->sort.addon_field)
+  {
+    info->rec_buf= table->sort.addon_buf;
+    info->ref_length= table->sort.addon_length;
+  }
+  else
+  {
+    info->record= table->record[0];
+    info->ref_length= table->file->ref_length;
+  }
   info->select=select;
   info->print_error=print_error;
   info->ignore_not_found_rows= 0;
@@ -51,11 +62,12 @@ void init_read_record(READ_RECORD *info,THD *thd, TABLE *table,
   if (select && my_b_inited(&select->file))
     tempfile= &select->file;
   else
-    tempfile= table->io_cache;
+    tempfile= table->sort.io_cache;
   if (tempfile && my_b_inited(tempfile)) // Test if ref-records was used
   {
     DBUG_PRINT("info",("using rr_from_tempfile"));
-    info->read_record=rr_from_tempfile;
+    info->read_record= (table->sort.addon_field ?
+                        rr_unpack_from_tempfile : rr_from_tempfile);
     info->io_cache=tempfile;
     reinit_io_cache(info->io_cache,READ_CACHE,0L,0,0);
     info->ref_pos=table->file->ref;
@@ -85,13 +97,15 @@ void init_read_record(READ_RECORD *info,THD *thd, TABLE *table,
     DBUG_PRINT("info",("using rr_quick"));
     info->read_record=rr_quick;
   }
-  else if (table->record_pointers)
+  else if (table->sort.record_pointers)
   {
     DBUG_PRINT("info",("using record_pointers"));
     table->file->rnd_init(0);
-    info->cache_pos=table->record_pointers;
-    info->cache_end=info->cache_pos+ table->found_records*info->ref_length;
-    info->read_record= rr_from_pointers;
+    info->cache_pos=table->sort.record_pointers;
+    info->cache_end=info->cache_pos+ 
+                    table->sort.found_records*info->ref_length;
+    info->read_record= (table->sort.addon_field ?
+                        rr_unpack_from_buffer : rr_from_pointers);
   }
   else
   {
@@ -120,6 +134,19 @@ void end_read_record(READ_RECORD *info)
   }
   if (info->table)
   {
+    TABLE *table= info->table;
+    if (table->sort.record_pointers)
+    {
+      my_free((gptr) table->sort.record_pointers,MYF(0));
+      table->sort.record_pointers=0;
+    }
+    if (table->sort.addon_buf)
+    {
+      my_free((char *) table->sort.addon_buf, MYF(0));
+      my_free((char *) table->sort.addon_field, MYF(MY_ALLOW_ZERO_PTR));
+      table->sort.addon_buf=0;
+      table->sort.addon_field=0;
+    }
     (void) info->file->extra(HA_EXTRA_NO_CACHE);
     (void) info->file->rnd_end();
     info->table=0;
@@ -200,6 +227,34 @@ tryNext:
 } /* rr_from_tempfile */
 
 
+/*
+  Read a result set record from a temporary file after sorting
+
+  SYNOPSIS
+    rr_unpack_from_tempfile()
+    info                Reference to the context including record descriptors
+
+  DESCRIPTION
+    The function first reads the next sorted record from the temporary file.
+    into a buffer. If a success it calls a callback function that unpacks 
+    the fields values use in the result set from this buffer into their
+    positions in the regular record buffer.
+
+  RETURN
+     0 - Record successfully read.
+    -1 - There is no record to be read anymore. 
+*/
+
+static int rr_unpack_from_tempfile(READ_RECORD *info)
+{
+  if (my_b_read(info->io_cache, info->rec_buf, info->ref_length))
+    return -1;
+  TABLE *table= info->table;
+  (*table->sort.unpack)(table->sort.addon_field, info->rec_buf);
+
+  return 0;
+}
+
 static int rr_from_pointers(READ_RECORD *info)
 {
   int tmp;
@@ -228,6 +283,34 @@ tryNext:
   return tmp;
 }
 
+/*
+  Read a result set record from a buffer after sorting
+
+  SYNOPSIS
+    rr_unpack_from_buffer()
+    info                   Reference to the context including record descriptors
+
+  DESCRIPTION
+    The function first reads the next sorted record from the sort buffer.
+    If a success it calls a callback function that unpacks 
+    the fields values use in the result set from this buffer into their
+    positions in the regular record buffer.
+
+  RETURN
+     0 - Record successfully read.
+    -1 - There is no record to be read anymore. 
+*/
+
+static int rr_unpack_from_buffer(READ_RECORD *info)
+{
+  if (info->cache_pos == info->cache_end)
+    return -1;                      /* End of buffer */
+  TABLE *table= info->table;
+  (*table->sort.unpack)(table->sort.addon_field, info->cache_pos);
+  info->cache_pos+= info->ref_length;
+
+  return 0;
+}
 	/* cacheing of records from a database */
 
 static int init_rr_cache(READ_RECORD *info)

sql/set_var.cc

@@ -166,6 +166,8 @@ sys_var_thd_ulong       sys_pseudo_thread_id("pseudo_thread_id",
 sys_var_thd_ha_rows	sys_max_join_size("max_join_size",
 					  &SV::max_join_size,
 					  fix_max_join_size);
+sys_var_thd_ulong   sys_max_length_for_sort_data("max_length_for_sort_data",
+                        &SV::max_length_for_sort_data);
 #ifndef TO_BE_DELETED	/* Alias for max_join_size */
 sys_var_thd_ha_rows	sys_sql_max_join_size("sql_max_join_size",
 					      &SV::max_join_size,
@@ -380,6 +382,7 @@ sys_var *sys_variables[]=
   &sys_max_error_count,
   &sys_max_heap_table_size,
   &sys_max_join_size,
+  &sys_max_length_for_sort_data,
   &sys_max_prep_stmt_count,
   &sys_max_sort_length,
   &sys_max_tmp_tables,
@@ -533,6 +536,9 @@ struct show_var_st init_vars[]= {
   {sys_max_delayed_threads.name,(char*) &sys_max_delayed_threads,   SHOW_SYS},
   {sys_max_heap_table_size.name,(char*) &sys_max_heap_table_size,   SHOW_SYS},
   {sys_max_join_size.name,	(char*) &sys_max_join_size,	    SHOW_SYS},
+  {sys_max_length_for_sort_data.name,
+   (char*) &sys_max_length_for_sort_data,
+   SHOW_SYS},
   {sys_max_prep_stmt_count.name,(char*) &sys_max_prep_stmt_count,   SHOW_SYS},
   {sys_max_sort_length.name,	(char*) &sys_max_sort_length,	    SHOW_SYS},
   {sys_max_user_connections.name,(char*) &sys_max_user_connections, SHOW_SYS},

sql/sql_base.cc

@@ -245,16 +245,11 @@ static void free_cache_entry(TABLE *table)
 void free_io_cache(TABLE *table)
 {
   DBUG_ENTER("free_io_cache");
-  if (table->io_cache)
+  if (table->sort.io_cache)
   {
-    close_cached_file(table->io_cache);
-    my_free((gptr) table->io_cache,MYF(0));
-    table->io_cache=0;
-  }
-  if (table->record_pointers)
-  {
-    my_free((gptr) table->record_pointers,MYF(0));
-    table->record_pointers=0;
+    close_cached_file(table->sort.io_cache);
+    my_free((gptr) table->sort.io_cache,MYF(0));
+    table->sort.io_cache=0;
   }
   DBUG_VOID_RETURN;
 }

sql/sql_class.h

@@ -352,6 +352,7 @@ struct system_variables
   ulong max_allowed_packet;
   ulong max_error_count;
   ulong max_heap_table_size;
+  ulong max_length_for_sort_data;
   ulong max_prep_stmt_count;
   ulong max_sort_length;
   ulong max_tmp_tables;

sql/sql_delete.cc

@@ -124,11 +124,11 @@ int mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds, ORDER *order,
     bzero((char*) &tables,sizeof(tables));
     tables.table = table;
 
-    table->io_cache = (IO_CACHE *) my_malloc(sizeof(IO_CACHE),
+    table->sort.io_cache = (IO_CACHE *) my_malloc(sizeof(IO_CACHE),
                                                   MYF(MY_FAE | MY_ZEROFILL));
     if (setup_order(thd, 0, &tables, fields, all_fields, order) ||
         !(sortorder=make_unireg_sortorder(order, &length)) ||
-        (table->found_records = filesort(thd, table, sortorder, length,
+        (table->sort.found_records = filesort(thd, table, sortorder, length,
                                               (SQL_SELECT *) 0, HA_POS_ERROR,
                                               &examined_rows))
         == HA_POS_ERROR)

sql/sql_select.cc

@@ -4009,7 +4009,7 @@ Field *create_tmp_field(THD *thd, TABLE *table,Item *item, Item::Type type,
     case Item_sum::AVG_FUNC:			/* Place for sum & count */
       if (group)
 	return new Field_string(sizeof(double)+sizeof(longlong),
-				maybe_null, item->name,table,&my_charset_bin);
+				0, item->name,table,&my_charset_bin);
       else
 	return new Field_double(item_sum->max_length,maybe_null,
 				item->name, table, item_sum->decimals);
@@ -4017,7 +4017,7 @@ Field *create_tmp_field(THD *thd, TABLE *table,Item *item, Item::Type type,
     case Item_sum::STD_FUNC:	
       if (group)
 	return	new Field_string(sizeof(double)*2+sizeof(longlong),
-				 maybe_null, item->name,table,&my_charset_bin);
+				 0, item->name,table,&my_charset_bin);
       else
 	return new Field_double(item_sum->max_length, maybe_null,
 				item->name,table,item_sum->decimals);				
@@ -5621,11 +5621,11 @@ end_send(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
 	  TABLE *table=jt->table;
 
 	  join->select_options ^= OPTION_FOUND_ROWS;
-	  if (table->record_pointers ||
-	      (table->io_cache && my_b_inited(table->io_cache)))
+	  if (table->sort.record_pointers ||
+	      (table->sort.io_cache && my_b_inited(table->sort.io_cache)))
 	  {
 	    /* Using filesort */
-	    join->send_records= table->found_records;
+	    join->send_records= table->sort.found_records;
 	  }
 	  else
 	  {
@@ -6460,7 +6460,7 @@ create_sort_index(THD *thd, JOIN_TAB *tab, ORDER *order,
   if (!(sortorder=make_unireg_sortorder(order,&length)))
     goto err;				/* purecov: inspected */
   /* It's not fatal if the following alloc fails */
-  table->io_cache=(IO_CACHE*) my_malloc(sizeof(IO_CACHE),
+  table->sort.io_cache=(IO_CACHE*) my_malloc(sizeof(IO_CACHE),
                                              MYF(MY_WME | MY_ZEROFILL));
   table->status=0;				// May be wrong if quick_select
 
@@ -6490,9 +6490,9 @@ create_sort_index(THD *thd, JOIN_TAB *tab, ORDER *order,
   }
   if (table->tmp_table)
     table->file->info(HA_STATUS_VARIABLE);	// Get record count
-  table->found_records=filesort(thd, table,sortorder, length,
+  table->sort.found_records=filesort(thd, table,sortorder, length,
                                      select, filesort_limit, &examined_rows);
-  tab->records=table->found_records;		// For SQL_CALC_ROWS
+  tab->records=table->sort.found_records;		// For SQL_CALC_ROWS
   delete select;				// filesort did select
   tab->select=0;
   tab->select_cond=0;
@@ -6504,7 +6504,7 @@ create_sort_index(THD *thd, JOIN_TAB *tab, ORDER *order,
     table->key_read=0;
     table->file->extra(HA_EXTRA_NO_KEYREAD);
   }
-  DBUG_RETURN(table->found_records == HA_POS_ERROR);
+  DBUG_RETURN(table->sort.found_records == HA_POS_ERROR);
 err:
   DBUG_RETURN(-1);
 }

sql/sql_sort.h

@@ -19,6 +19,30 @@
 #define MERGEBUFF		7
 #define MERGEBUFF2		15
 
+/*
+   The structure SORT_ADDON_FIELD describes a fixed layout
+   for field values appended to sorted values in records to be sorted
+   in the sort buffer.
+   Only fixed layout is supported now.
+   Null bit maps for the appended values is placed before the values 
+   themselves. Offsets are from the last sorted field, that is from the
+   record referefence, which is still last component of sorted records.
+   It is preserved for backward compatiblility.
+   The structure is used tp store values of the additional fields 
+   in the sort buffer. It is used also when these values are read
+   from a temporary file/buffer. As the reading procedures are beyond the
+   scope of the 'filesort' code the values have to be retrieved via
+   the callback function 'unpack_addon_fields'.
+*/
+
+typedef struct st_sort_addon_field {  /* Sort addon packed field */
+  Field *field;          /* Original field */
+  uint   offset;         /* Offset from the last sorted field */
+  uint   null_offset;    /* Offset to to null bit from the last sorted field */
+  uint   length;         /* Length in the sort buffer */
+  uint8  null_bit;       /* Null bit mask for the field */
+} SORT_ADDON_FIELD;
+
 typedef struct st_buffpek {		/* Struktur om sorteringsbuffrarna */
   my_off_t file_pos;			/* Where we are in the sort file */
   uchar *base,*key;			/* key pointers */
@@ -27,15 +51,18 @@ typedef struct st_buffpek {		/* Struktur om sorteringsbuffrarna */
   ulong max_keys;			/* Max keys in buffert */
 } BUFFPEK;
 
-
 typedef struct st_sort_param {
-  uint sort_length;			/* Length of sort columns */
-  uint keys;				/* Max keys / buffert */
+  uint rec_length;          /* Length of sorted records */
+  uint sort_length;			/* Length of sorted columns */
   uint ref_length;			/* Length of record ref. */
+  uint addon_length;        /* Length of added packed fields */
+  uint res_length;          /* Length of records in final sorted file/buffer */
+  uint keys;				/* Max keys / buffer */
   ha_rows max_rows,examined_rows;
   TABLE *sort_form;			/* For quicker make_sortkey */
   SORT_FIELD *local_sortorder;
   SORT_FIELD *end;
+  SORT_ADDON_FIELD *addon_field; /* Descriptors for companion fields */
   uchar *unique_buff;
   bool not_killable;
   char* tmp_buffer;

sql/sql_table.cc

@@ -2342,7 +2342,7 @@ copy_data_between_tables(TABLE *from,TABLE *to,
 
   if (order)
   {
-    from->io_cache=(IO_CACHE*) my_malloc(sizeof(IO_CACHE),
+    from->sort.io_cache=(IO_CACHE*) my_malloc(sizeof(IO_CACHE),
                                               MYF(MY_FAE | MY_ZEROFILL));
     bzero((char*) &tables,sizeof(tables));
     tables.table = from;
@@ -2355,7 +2355,7 @@ copy_data_between_tables(TABLE *from,TABLE *to,
 	setup_order(thd, thd->lex.select_lex.ref_pointer_array,
 		    &tables, fields, all_fields, order) ||
         !(sortorder=make_unireg_sortorder(order, &length)) ||
-        (from->found_records = filesort(thd, from, sortorder, length, 
+        (from->sort.found_records = filesort(thd, from, sortorder, length, 
                                              (SQL_SELECT *) 0, HA_POS_ERROR,
                                              &examined_rows))
         == HA_POS_ERROR)

sql/sql_update.cc

@@ -201,14 +201,14 @@ int mysql_update(THD *thd,
       bzero((char*) &tables,sizeof(tables));
       tables.table = table;
 
-      table->io_cache = (IO_CACHE *) my_malloc(sizeof(IO_CACHE),
+      table->sort.io_cache = (IO_CACHE *) my_malloc(sizeof(IO_CACHE),
                                                MYF(MY_FAE | MY_ZEROFILL));
       if (setup_ref_array(thd, &thd->lex.select_lex.ref_pointer_array,
 			order_num)||
 	  setup_order(thd, thd->lex.select_lex.ref_pointer_array,
 		      &tables, fields, all_fields, order) ||
           !(sortorder=make_unireg_sortorder(order, &length)) ||
-          (table->found_records = filesort(thd, table, sortorder, length,
+          (table->sort.found_records = filesort(thd, table, sortorder, length,
                                            (SQL_SELECT *) 0,
 					   HA_POS_ERROR, &examined_rows))
           == HA_POS_ERROR)

sql/structs.h

@@ -104,6 +104,7 @@ typedef struct st_read_record {			/* Parameter to read_record */
   uint index;
   byte *ref_pos;				/* pointer to form->refpos */
   byte *record;
+  byte *rec_buf;                /* to read field values  after filesort */
   byte	*cache,*cache_pos,*cache_end,*read_positions;
   IO_CACHE *io_cache;
   bool print_error, ignore_not_found_rows;

sql/table.h

@@ -44,6 +44,17 @@ typedef struct st_grant_info
 
 enum tmp_table_type {NO_TMP_TABLE=0, TMP_TABLE=1, TRANSACTIONAL_TMP_TABLE=2};
 
+typedef struct st_filesort_info
+{
+  IO_CACHE *io_cache;           /* If sorted through filebyte                */
+  byte     *addon_buf;          /* Pointer to a buffer if sorted with fields */
+  uint      addon_length;       /* Length of the buffer                      */
+  struct st_sort_addon_field *addon_field;     /* Pointer to the fields info */
+  void    (*unpack)(struct st_sort_addon_field *, byte *); /* To unpack back */
+  byte     *record_pointers;    /* If sorted in memory                       */
+  ha_rows   found_records;      /* How many records in sort                  */
+} FILESORT_INFO;
+
 /* Table cache entry struct */
 
 class Field_timestamp;
@@ -120,9 +131,7 @@ struct st_table {
   table_map	map;                    /* ID bit of table (1,2,4,8,16...) */
   ulong		version,flush_version;
   uchar		*null_flags;
-  IO_CACHE	*io_cache;		/* If sorted trough filebyte */
-  byte		*record_pointers;	/* If sorted in memory */
-  ha_rows	found_records;		/* How many records in sort */
+  FILESORT_INFO sort;
   ORDER		*group;
   ha_rows	quick_rows[MAX_KEY];
   uint		quick_key_parts[MAX_KEY];

sql/uniques.cc

@@ -95,12 +95,12 @@ bool Unique::flush()
 bool Unique::get(TABLE *table)
 {
   SORTPARAM sort_param;
-  table->found_records=elements+tree.elements_in_tree;
+  table->sort.found_records=elements+tree.elements_in_tree;
 
   if (my_b_tell(&file) == 0)
   {
     /* Whole tree is in memory;  Don't use disk if you don't need to */
-    if ((record_pointers=table->record_pointers= (byte*)
+    if ((record_pointers=table->sort.record_pointers= (byte*)
 	 my_malloc(tree.size_of_element * tree.elements_in_tree, MYF(0))))
     {
       (void) tree_walk(&tree, (tree_walk_action) unique_write_to_ptrs,
@@ -112,7 +112,7 @@ bool Unique::get(TABLE *table)
   if (flush())
     return 1;
 
-  IO_CACHE *outfile=table->io_cache;
+  IO_CACHE *outfile=table->sort.io_cache;
   BUFFPEK *file_ptr= (BUFFPEK*) file_ptrs.buffer;
   uint maxbuffer= file_ptrs.elements - 1;
   uchar *sort_buffer;
@@ -120,7 +120,7 @@ bool Unique::get(TABLE *table)
   bool error=1;
 
       /* Open cached file if it isn't open */
-  outfile=table->io_cache=(IO_CACHE*) my_malloc(sizeof(IO_CACHE),
+  outfile=table->sort.io_cache=(IO_CACHE*) my_malloc(sizeof(IO_CACHE), 
                                 MYF(MY_ZEROFILL));
 
   if (!outfile || ! my_b_inited(outfile) &&