Commit 4025d296 authored by ingo@mysql.com's avatar ingo@mysql.com
Browse files

Bug#9112 - Merge table with composite index producing invalid results with some queries 

The problem was an ab-use of last_rkey_length.
Formerly we saved the packed key length (of the search key)
in this element. But in certain cases it got replaced by 
the (packed) result key length.
Now we use a new element of MI_INFO to save the packed key 
length of the search key.
parent a8bdf632

myisam/mi_dbug.c

+2 −2
Original line number Diff line number Diff line
@@ -40,12 +40,12 @@ void _mi_print_key(FILE *stream, register MI_KEYSEG *keyseg, 
    end= key+ keyseg->length;

    if (keyseg->flag & HA_NULL_PART)

    {

      if (!*key)

      /* A NULL value is encoded by a 1-byte flag. Zero means NULL. */

      if (! *(key++))

      {

	fprintf(stream,"NULL");

	continue;

      }

      key++;

    }



    switch (keyseg->type) {

myisam/mi_rkey.c

+5 −2
Original line number Diff line number Diff line
@@ -31,8 +31,8 @@ int mi_rkey(MI_INFO *info, byte *buf, int inx, const byte *key, uint key_len, 
  MI_KEYSEG *last_used_keyseg;

  uint pack_key_length, use_key_length, nextflag;

  DBUG_ENTER("mi_rkey");

  DBUG_PRINT("enter",("base: %lx  inx: %d  search_flag: %d",

		      info,inx,search_flag));

  DBUG_PRINT("enter", ("base: %p  buf: %p  inx: %d  search_flag: %d",

                       info, buf, inx, search_flag));



  if ((inx = _mi_check_index(info,inx)) < 0)

    DBUG_RETURN(my_errno);
@@ -44,9 +44,12 @@ int mi_rkey(MI_INFO *info, byte *buf, int inx, const byte *key, uint key_len, 
  {

    if (key_len == 0)

      key_len=USE_WHOLE_KEY;

    /* Save the packed key for later use in the second buffer of lastkey. */

    key_buff=info->lastkey+info->s->base.max_key_length;

    pack_key_length=_mi_pack_key(info, (uint) inx, key_buff, (uchar*) key,

				 key_len, &last_used_keyseg);

    /* Save packed_key_length for use by the MERGE engine. */

    info->pack_key_length= pack_key_length;

    DBUG_EXECUTE("key",_mi_print_key(DBUG_FILE, keyinfo->seg,

				     key_buff, pack_key_length););

  }

myisam/mi_search.c

+13 −3
Original line number Diff line number Diff line
@@ -1237,11 +1237,21 @@ uint _mi_get_binary_pack_key(register MI_KEYDEF *keyinfo, uint nod_flag, 
  reg1 MI_KEYSEG *keyseg;

  uchar *start_key,*page,*page_end,*from,*from_end;

  uint length,tmp;

  DBUG_ENTER("_mi_get_binary_pack_key");



  page= *page_pos;

  page_end=page+MI_MAX_KEY_BUFF+1;

  start_key=key;



  /*

    Keys are compressed the following way:



    prefix length    Packed length of prefix for the prev key. (1 or 3 bytes)

    for each key segment:

      [is null]        Null indicator if can be null (1 byte, zero means null)

      [length]         Packed length if varlength (1 or 3 bytes)

    pointer          Reference to the data file (last_keyseg->length).

  */

  get_key_length(length,page);

  if (length)

  {
@@ -1251,7 +1261,7 @@ uint _mi_get_binary_pack_key(register MI_KEYDEF *keyinfo, uint nod_flag, 
                          length, keyinfo->maxlength, *page_pos));

      DBUG_DUMP("key",(char*) *page_pos,16);

      my_errno=HA_ERR_CRASHED;

      return 0;                                 /* Wrong key */

      DBUG_RETURN(0);                                 /* Wrong key */

    }

    from=key;  from_end=key+length;

  }
@@ -1312,12 +1322,12 @@ uint _mi_get_binary_pack_key(register MI_KEYDEF *keyinfo, uint nod_flag, 
    {

      DBUG_PRINT("error",("Error when unpacking key"));

      my_errno=HA_ERR_CRASHED;

      return 0;                                 /* Error */

      DBUG_RETURN(0);                                 /* Error */

    }

    memcpy((byte*) key,(byte*) from,(size_t) length);

    *page_pos= from+length;

  }

  return((uint) (key-start_key)+keyseg->length);

  DBUG_RETURN((uint) (key-start_key)+keyseg->length);

}

myisam/myisamdef.h

+1 −0
Original line number Diff line number Diff line
@@ -255,6 +255,7 @@ struct st_myisam_info { 
  uint	lastkey_length;			/* Length of key in lastkey */

  uint	last_rkey_length;		/* Last length in mi_rkey() */

  uint  save_lastkey_length;

  uint  pack_key_length;                /* For MYISAMMRG */

  int	errkey;				/* Got last error on this key */

  int   lock_type;			/* How database was locked */

  int   tmp_lock_type;			/* When locked by readinfo */

myisammrg/myrg_rkey.c

+12 −5
Original line number Diff line number Diff line
@@ -44,11 +44,12 @@ int myrg_rkey(MYRG_INFO *info,byte *buf,int inx, const byte *key, 
  MYRG_TABLE *table;

  MI_INFO *mi;

  int err;

  DBUG_ENTER("myrg_rkey");

  LINT_INIT(key_buff);

  LINT_INIT(pack_key_length);



  if (_myrg_init_queue(info,inx,search_flag))

    return my_errno;

    DBUG_RETURN(my_errno);



  for (table=info->open_tables ; table != info->end_table ; table++)

  {
@@ -57,8 +58,9 @@ int myrg_rkey(MYRG_INFO *info,byte *buf,int inx, const byte *key, 
    if (table == info->open_tables)

    {

      err=mi_rkey(mi,0,inx,key,key_len,search_flag);

      /* Get the saved packed key and packed key length. */

      key_buff=(byte*) mi->lastkey+mi->s->base.max_key_length;

      pack_key_length=mi->last_rkey_length;

      pack_key_length=mi->pack_key_length;

    }

    else

    {
@@ -72,16 +74,21 @@ int myrg_rkey(MYRG_INFO *info,byte *buf,int inx, const byte *key, 
    {

      if (err == HA_ERR_KEY_NOT_FOUND)

	continue;

      return err;

      DBUG_PRINT("exit", ("err: %d", err));

      DBUG_RETURN(err);

    }

    /* adding to queue */

    queue_insert(&(info->by_key),(byte *)table);



  }



  DBUG_PRINT("info", ("tables with matches: %u", info->by_key.elements));

  if (!info->by_key.elements)

    return HA_ERR_KEY_NOT_FOUND;

    DBUG_RETURN(HA_ERR_KEY_NOT_FOUND);



  mi=(info->current_table=(MYRG_TABLE *)queue_top(&(info->by_key)))->table;

  return _myrg_mi_read_record(mi,buf);

  DBUG_PRINT("info", ("using table no: %d",

                      info->current_table - info->open_tables + 1));

  DBUG_DUMP("result key", (byte*) mi->lastkey, mi->lastkey_length);

  DBUG_RETURN(_myrg_mi_read_record(mi,buf));

}