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/* - mode: c; c-basic-offset: 2; indent-tabs-mode: nil; -*-
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* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
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* Copyright (C) 2008-2009 Sun Microsystems
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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* Implementation of the JOIN cache
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* @defgroup Query_Optimizer Query Optimizer
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#include "drizzled/sql_select.h" /* include join.h */
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#include "drizzled/field/blob.h"
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static uint32_t used_blob_length(CACHE_FIELD **ptr);
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static uint32_t used_blob_length(CACHE_FIELD **ptr)
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uint32_t length,blob_length;
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for (length=0 ; *ptr ; ptr++)
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(*ptr)->blob_length=blob_length=(*ptr)->blob_field->get_length();
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(*ptr)->blob_field->get_ptr(&(*ptr)->str);
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/*****************************************************************************
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Fill join cache with packed records
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Records are stored in tab->cache.buffer and last record in
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last record is stored with pointers to blobs to support very big
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******************************************************************************/
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int join_init_cache(Session *session, JoinTable *tables, uint32_t table_count)
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register unsigned int i;
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unsigned int length, blobs;
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CACHE_FIELD *copy,**blob_ptr;
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cache= &tables[table_count].cache;
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cache->fields=blobs=0;
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for (i=0 ; i < table_count ; i++,join_tab++)
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if (!join_tab->used_fieldlength) /* Not calced yet */
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calc_used_field_length(session, join_tab);
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cache->fields+=join_tab->used_fields;
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blobs+=join_tab->used_blobs;
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/* SemiJoinDuplicateElimination: reserve space for rowid */
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if (join_tab->rowid_keep_flags & JoinTable::KEEP_ROWID)
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join_tab->used_fieldlength += join_tab->table->cursor->ref_length;
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if (!(cache->field=(CACHE_FIELD*)
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memory::sql_alloc(sizeof(CACHE_FIELD)*(cache->fields+table_count*2)+(blobs+1)*
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sizeof(CACHE_FIELD*))))
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free((unsigned char*) cache->buff);
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blob_ptr=cache->blob_ptr=(CACHE_FIELD**)
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(cache->field+cache->fields+table_count*2);
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for (i=0 ; i < table_count ; i++)
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uint32_t null_fields=0, used_fields;
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Field **f_ptr,*field;
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for (f_ptr= tables[i].table->field,used_fields= tables[i].used_fields; used_fields; f_ptr++)
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if (field->isReadSet())
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length+=field->fill_cache_field(copy);
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if (copy->blob_field)
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if (field->maybe_null())
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copy->get_rowid= NULL;
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/* Copy null bits from table */
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if (null_fields && tables[i].table->getNullFields())
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{ /* must copy null bits */
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copy->str= tables[i].table->null_flags;
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copy->length= tables[i].table->s->null_bytes;
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copy->get_rowid= NULL;
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length+=copy->length;
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/* If outer join table, copy null_row flag */
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if (tables[i].table->maybe_null)
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copy->str= (unsigned char*) &tables[i].table->null_row;
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copy->length=sizeof(tables[i].table->null_row);
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copy->get_rowid= NULL;
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length+=copy->length;
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/* SemiJoinDuplicateElimination: Allocate space for rowid if needed */
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if (tables[i].rowid_keep_flags & JoinTable::KEEP_ROWID)
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copy->str= tables[i].table->cursor->ref;
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copy->length= tables[i].table->cursor->ref_length;
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copy->get_rowid= NULL;
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if (tables[i].rowid_keep_flags & JoinTable::CALL_POSITION)
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/* We will need to call h->position(): */
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copy->get_rowid= tables[i].table;
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/* And those after us won't have to: */
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tables[i].rowid_keep_flags&= ~((int)JoinTable::CALL_POSITION);
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cache->length= length+blobs*sizeof(char*);
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*blob_ptr= NULL; /* End sequentel */
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size= max((size_t) session->variables.join_buff_size, (size_t)cache->length);
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if (!(cache->buff= (unsigned char*) malloc(size)))
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cache->end= cache->buff+size;
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reset_cache_write(cache);
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bool store_record_in_cache(JOIN_CACHE *cache)
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CACHE_FIELD *copy,*end_field;
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end_field= cache->field+cache->fields;
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length= cache->length;
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length+= used_blob_length(cache->blob_ptr);
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if ((last_record= (length + cache->length > (size_t) (cache->end - pos))))
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cache->ptr_record= cache->records;
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There is room in cache. Put record there
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for (copy= cache->field; copy < end_field; copy++)
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if (copy->blob_field)
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copy->blob_field->get_image(pos, copy->length+sizeof(char*), copy->blob_field->charset());
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pos+= copy->length+sizeof(char*);
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copy->blob_field->get_image(pos, copy->length, // blob length
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copy->blob_field->charset());
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memcpy(pos+copy->length,copy->str,copy->blob_length); // Blob data
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pos+= copy->length+copy->blob_length;
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// SemiJoinDuplicateElimination: Get the rowid into table->ref:
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copy->get_rowid->cursor->position(copy->get_rowid->record[0]);
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unsigned char *str,*end;
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for (str= copy->str,end= str+copy->length; end > str && end[-1] == ' '; end--)
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length= (uint32_t) (end-str);
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memcpy(pos+2, str, length);
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int2store(pos, length);
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memcpy(pos,copy->str,copy->length);
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return last_record || (size_t) (cache->end - pos) < cache->length;
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void reset_cache_read(JOIN_CACHE *cache)
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cache->pos= cache->buff;
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void reset_cache_write(JOIN_CACHE *cache)
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reset_cache_read(cache);
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cache->ptr_record= UINT32_MAX;
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@} (end of group Query_Optimizer)
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} /* namespace drizzled */