diff options
Diffstat (limited to 'sql/group_by_handler.cc')
| -rw-r--r-- | sql/group_by_handler.cc | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/sql/group_by_handler.cc b/sql/group_by_handler.cc new file mode 100644 index 00000000..7b998494 --- /dev/null +++ b/sql/group_by_handler.cc @@ -0,0 +1,145 @@ +/* + 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->limit_params.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_with_check(*join->fields, + join->unit, + join->send_records)))) + { + 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); +} |