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/* - mode: c; c-basic-offset: 2; indent-tabs-mode: nil; -*-
* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
*
* Copyright (C) 2008-2009 Sun Microsystems
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
*
* Implementation of the JOIN cache
*
* @defgroup Query_Optimizer Query Optimizer
* @{
*/
#include "config.h"
#include "drizzled/sql_select.h" /* include join.h */
#include "drizzled/field/blob.h"
#include <algorithm>
using namespace std;
namespace drizzled
{
static uint32_t used_blob_length(CACHE_FIELD **ptr);
static uint32_t used_blob_length(CACHE_FIELD **ptr)
{
uint32_t length,blob_length;
for (length=0 ; *ptr ; ptr++)
{
(*ptr)->blob_length=blob_length=(*ptr)->blob_field->get_length();
length+=blob_length;
(*ptr)->blob_field->get_ptr(&(*ptr)->str);
}
return length;
}
/*****************************************************************************
Fill join cache with packed records
Records are stored in tab->cache.buffer and last record in
last record is stored with pointers to blobs to support very big
records
******************************************************************************/
int join_init_cache(Session *session, JoinTable *tables, uint32_t table_count)
{
register unsigned int i;
unsigned int length, blobs;
size_t size;
CACHE_FIELD *copy,**blob_ptr;
JOIN_CACHE *cache;
JoinTable *join_tab;
cache= &tables[table_count].cache;
cache->fields=blobs=0;
join_tab= tables;
for (i=0 ; i < table_count ; i++,join_tab++)
{
if (!join_tab->used_fieldlength) /* Not calced yet */
calc_used_field_length(session, join_tab);
cache->fields+=join_tab->used_fields;
blobs+=join_tab->used_blobs;
/* SemiJoinDuplicateElimination: reserve space for rowid */
if (join_tab->rowid_keep_flags & JoinTable::KEEP_ROWID)
{
cache->fields++;
join_tab->used_fieldlength += join_tab->table->cursor->ref_length;
}
}
if (!(cache->field=(CACHE_FIELD*)
memory::sql_alloc(sizeof(CACHE_FIELD)*(cache->fields+table_count*2)+(blobs+1)*
sizeof(CACHE_FIELD*))))
{
free((unsigned char*) cache->buff);
cache->buff=0;
return(1);
}
copy=cache->field;
blob_ptr=cache->blob_ptr=(CACHE_FIELD**)
(cache->field+cache->fields+table_count*2);
length=0;
for (i=0 ; i < table_count ; i++)
{
uint32_t null_fields=0, used_fields;
Field **f_ptr,*field;
for (f_ptr= tables[i].table->field,used_fields= tables[i].used_fields; used_fields; f_ptr++)
{
field= *f_ptr;
if (field->isReadSet())
{
used_fields--;
length+=field->fill_cache_field(copy);
if (copy->blob_field)
(*blob_ptr++)=copy;
if (field->maybe_null())
null_fields++;
copy->get_rowid= NULL;
copy++;
}
}
/* Copy null bits from table */
if (null_fields && tables[i].table->getNullFields())
{ /* must copy null bits */
copy->str= tables[i].table->null_flags;
copy->length= tables[i].table->s->null_bytes;
copy->strip=0;
copy->blob_field=0;
copy->get_rowid= NULL;
length+=copy->length;
copy++;
cache->fields++;
}
/* If outer join table, copy null_row flag */
if (tables[i].table->maybe_null)
{
copy->str= (unsigned char*) &tables[i].table->null_row;
copy->length=sizeof(tables[i].table->null_row);
copy->strip=0;
copy->blob_field=0;
copy->get_rowid= NULL;
length+=copy->length;
copy++;
cache->fields++;
}
/* SemiJoinDuplicateElimination: Allocate space for rowid if needed */
if (tables[i].rowid_keep_flags & JoinTable::KEEP_ROWID)
{
copy->str= tables[i].table->cursor->ref;
copy->length= tables[i].table->cursor->ref_length;
copy->strip=0;
copy->blob_field=0;
copy->get_rowid= NULL;
if (tables[i].rowid_keep_flags & JoinTable::CALL_POSITION)
{
/* We will need to call h->position(): */
copy->get_rowid= tables[i].table;
/* And those after us won't have to: */
tables[i].rowid_keep_flags&= ~((int)JoinTable::CALL_POSITION);
}
copy++;
}
}
cache->length= length+blobs*sizeof(char*);
cache->blobs= blobs;
*blob_ptr= NULL; /* End sequentel */
size= max((size_t) session->variables.join_buff_size, (size_t)cache->length);
if (!(cache->buff= (unsigned char*) malloc(size)))
return 1;
cache->end= cache->buff+size;
reset_cache_write(cache);
return 0;
}
bool store_record_in_cache(JOIN_CACHE *cache)
{
uint32_t length;
unsigned char *pos;
CACHE_FIELD *copy,*end_field;
bool last_record;
pos= cache->pos;
end_field= cache->field+cache->fields;
length= cache->length;
if (cache->blobs)
length+= used_blob_length(cache->blob_ptr);
if ((last_record= (length + cache->length > (size_t) (cache->end - pos))))
cache->ptr_record= cache->records;
/*
There is room in cache. Put record there
*/
cache->records++;
for (copy= cache->field; copy < end_field; copy++)
{
if (copy->blob_field)
{
if (last_record)
{
copy->blob_field->get_image(pos, copy->length+sizeof(char*), copy->blob_field->charset());
pos+= copy->length+sizeof(char*);
}
else
{
copy->blob_field->get_image(pos, copy->length, // blob length
copy->blob_field->charset());
memcpy(pos+copy->length,copy->str,copy->blob_length); // Blob data
pos+= copy->length+copy->blob_length;
}
}
else
{
// SemiJoinDuplicateElimination: Get the rowid into table->ref:
if (copy->get_rowid)
copy->get_rowid->cursor->position(copy->get_rowid->record[0]);
if (copy->strip)
{
unsigned char *str,*end;
for (str= copy->str,end= str+copy->length; end > str && end[-1] == ' '; end--)
{}
length= (uint32_t) (end-str);
memcpy(pos+2, str, length);
int2store(pos, length);
pos+= length+2;
}
else
{
memcpy(pos,copy->str,copy->length);
pos+= copy->length;
}
}
}
cache->pos= pos;
return last_record || (size_t) (cache->end - pos) < cache->length;
}
void reset_cache_read(JOIN_CACHE *cache)
{
cache->record_nr= 0;
cache->pos= cache->buff;
}
void reset_cache_write(JOIN_CACHE *cache)
{
reset_cache_read(cache);
cache->records= 0;
cache->ptr_record= UINT32_MAX;
}
/**
@} (end of group Query_Optimizer)
*/
} /* namespace drizzled */
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