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/*
Copyright (c) 2014, 2015 SkySQL Ab & MariaDB Foundation
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; version 2 of the License.
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 Street, Fifth Floor, Boston, MA 02110-1335 USA */
/*
This file implements the group_by_handler code. This interface
can be used by storage handlers that can intercept summary or GROUP
BY queries from MariaDB and itself return the result to the user or
upper level.
*/
#include "mariadb.h"
#include "sql_priv.h"
#include "sql_select.h"
/*
Same return values as do_select();
@retval
0 if ok
@retval
1 if error is sent
@retval
-1 if error should be sent
*/
int Pushdown_query::execute(JOIN *join)
{
int err;
ha_rows max_limit;
bool reset_limit= FALSE;
Item **reset_item= 0;
THD *thd= handler->thd;
TABLE *table= handler->table;
DBUG_ENTER("Pushdown_query::execute");
if ((err= handler->init_scan()))
goto error;
if (store_data_in_temp_table)
{
max_limit= join->tmp_table_param.end_write_records;
reset_limit= TRUE;
}
else
{
max_limit= join->unit->lim.get_select_limit();
if (join->unit->fake_select_lex)
reset_item= &join->unit->fake_select_lex->select_limit;
}
while (!(err= handler->next_row()))
{
if (unlikely(thd->check_killed()))
{
handler->end_scan();
DBUG_RETURN(-1);
}
/* Check if we can accept the row */
if (!having || having->val_bool())
{
if (store_data_in_temp_table)
{
if ((err= table->file->ha_write_tmp_row(table->record[0])))
{
bool is_duplicate;
if (likely(!table->file->is_fatal_error(err, HA_CHECK_DUP)))
continue; // Distinct elimination
if (create_internal_tmp_table_from_heap(thd, table,
join->tmp_table_param.
start_recinfo,
&join->tmp_table_param.
recinfo,
err, 1, &is_duplicate))
DBUG_RETURN(1);
if (is_duplicate)
continue;
}
}
else
{
if (join->do_send_rows)
{
int error;
/* result < 0 if row was not accepted and should not be counted */
if (unlikely((error= join->result->send_data(*join->fields))))
{
handler->end_scan();
DBUG_RETURN(error < 0 ? 0 : -1);
}
}
}
/* limit handling */
if (++join->send_records >= max_limit && join->do_send_rows)
{
if (!(join->select_options & OPTION_FOUND_ROWS))
break; // LIMIT reached
join->do_send_rows= 0; // Calculate FOUND_ROWS()
if (reset_limit)
join->unit->lim.set_unlimited();
if (reset_item)
*reset_item= 0;
}
}
}
if (err != 0 && err != HA_ERR_END_OF_FILE)
goto error;
if ((err= handler->end_scan()))
goto error_2;
if (!store_data_in_temp_table && join->result->send_eof())
DBUG_RETURN(1); // Don't send error to client
DBUG_RETURN(0);
error:
handler->end_scan();
error_2:
handler->print_error(err, MYF(0));
DBUG_RETURN(-1); // Error not sent to client
}
void group_by_handler::print_error(int error, myf errflag)
{
my_error(ER_GET_ERRNO, MYF(0), error, hton_name(ht)->str);
}
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