Added Unique class to be used for duplicate removal in multi-table delete.

mysys/ptr_cmp.c:
  Removed old comments
pstack/bucomm.c:
  Change to use mkstemp.
sql/Makefile.am:
  Added Unique class
sql/filesort.cc:
  Changes to let the Unique class use the old filesort code.
sql/sql_class.h:
  Added Unique class
sql/sql_handler.cc:
  Removed warning.
sql/sql_select.cc:
  Cleaned up typo.

1 files changed, 160 insertions, 0 deletions

diff --git a/sql/uniques.cc b/sql/uniques.cc
new file mode 100644
index 00000000000..78fd8fe6e60
--- /dev/null
+++ b/sql/uniques.cc
@@ -0,0 +1,160 @@
+/* Copyright (C) 2001 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+/*
+  Function to handle quick removal of duplicates
+  This code is used when doing multi-table deletes to find the rows in
+  reference tables that needs to be deleted.
+
+  The basic idea is as follows:
+
+  Store first all strings in a binary tree, ignoring duplicates.
+  When the three uses more memory than 'max_heap_table_size',
+  write the tree (in sorted order) out to disk and start with a new tree.
+  When all data has been generated, merge the trees (removing any found
+  duplicates).
+
+  The unique entries will be returned in sort order, to ensure that we do the
+  deletes in disk order.
+*/
+
+#include "mysql_priv.h"
+#include "sql_sort.h"
+
+Unique::Unique(qsort_cmp2 comp_func, uint size, ulong max_in_memory_size_arg)
+  :max_in_memory_size(max_in_memory_size_arg),elements(0)
+{
+  my_b_clear(&file);
+  init_tree(&tree, max_in_memory_size / 16, size, comp_func, 0, 0);
+  /* If the following fail's the next add will also fail */
+  init_dynamic_array(&file_ptrs, sizeof(BUFFPEK), 16, 16);
+  max_elements= max_in_memory_size / ALIGN_SIZE(sizeof(TREE_ELEMENT)+size);
+}
+
+
+Unique::~Unique()
+{
+  close_cached_file(&file);
+  delete_tree(&tree);
+  delete_dynamic(&file_ptrs);
+}
+
+
+    /* Write tree to disk; clear tree */    
+bool Unique::flush()
+{
+  BUFFPEK file_ptr;
+  elements+= tree.elements_in_tree;
+  file_ptr.count=tree.elements_in_tree;
+  file_ptr.file_pos=my_b_tell(&file);
+  if (tree_walk(&tree, (tree_walk_action) unique_write_to_file,
+		(void*) this, left_root_right) ||
+      insert_dynamic(&file_ptrs, (gptr) &file_ptr))
+    return 1;
+  delete_tree(&tree);
+  return 0;
+}
+
+
+int unique_write_to_file(gptr key, Unique *unique,  element_count count)
+{
+  return my_b_write(&unique->file, key, unique->tree.size_of_element) ? 1 : 0;
+}
+
+int unique_write_to_ptrs(gptr key, Unique *unique,  element_count count)
+{
+  memcpy(unique->record_pointers, key, unique->tree.size_of_element);
+  unique->record_pointers+=unique->tree.size_of_element;
+  return 0;
+}
+
+
+/*
+  Modify the TABLE element so that when one calls init_records()
+  the rows will be read in priority order.
+*/
+
+bool Unique::get(TABLE *table)
+{
+  SORTPARAM sort_param;
+  table->found_records=elements+tree.elements_in_tree;
+
+  if (!my_b_inited(&file))
+  {
+    /* Whole tree is in memory;  Don't use disk if you don't need to */
+    if ((record_pointers=table->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,
+		       this, left_root_right);
+      return 0;
+    }
+  }
+  /* Not enough memory; Save the result to file */
+  if (flush())
+    return 1;
+
+  IO_CACHE *outfile=table->io_cache, tempfile;
+  BUFFPEK *file_ptr= (BUFFPEK*) file_ptrs.buffer;
+  uint maxbuffer= file_ptrs.elements;
+  uchar *sort_buffer;
+  my_off_t save_pos;
+  bool error=1;
+
+  my_b_clear(&tempfile);
+
+      /* Open cached file if it isn't open */
+  if (! my_b_inited(outfile) &&
+      open_cached_file(outfile,mysql_tmpdir,TEMP_PREFIX,READ_RECORD_BUFFER,
+		       MYF(MY_WME)))
+    return 1;
+  reinit_io_cache(outfile,WRITE_CACHE,0L,0,0);
+
+  sort_param.keys=elements;
+  sort_param.sort_form=table;
+  sort_param.sort_length=sort_param.ref_length=tree.size_of_element;
+  sort_param.keys= max_in_memory_size / sort_param.sort_length;
+  
+  if (!(sort_buffer=(uchar*) my_malloc((sort_param.keys+1) *
+				      sort_param.sort_length,
+				      MYF(0))))
+    return 1;
+  sort_param.unique_buff= sort_buffer+(sort_param.keys*
+				       sort_param.sort_length);
+
+  /* Merge the buffers to one file, removing duplicates */
+  if (merge_many_buff(&sort_param,sort_buffer,file_ptr,&maxbuffer,&tempfile))
+    goto err;
+  if (flush_io_cache(&tempfile) ||
+      reinit_io_cache(&tempfile,READ_CACHE,0L,0,0))
+    goto err;
+  if (merge_buffers(&sort_param, &tempfile, outfile, sort_buffer, file_ptr,
+		    file_ptr, file_ptr+maxbuffer,0))
+    goto err;                                                                 
+  error=0;
+err:
+  x_free((gptr) sort_buffer);
+  close_cached_file(&tempfile);
+  if (flush_io_cache(outfile))
+    error=1;
+
+  /* Setup io_cache for reading */
+  save_pos=outfile->pos_in_file;
+  if (reinit_io_cache(outfile,READ_CACHE,0L,0,0))
+    error=1;
+  outfile->end_of_file=save_pos;
+  return error;
+}