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mariadb/sql/sql_delete.cc
Varun Gupta 6f4534e622 MDEV-14695: Assertion `n < m_size' failed in Bounds_checked_array<Element_type>::operator 
In this issue we hit the assert because we are adding addition fields to the field JOIN::all_fields list. This
is done because  HEAP tables can't index BIT fields so  we need to use an additional hidden field for grouping because later it will be
converted to a LONG field. Original field will remain of the BIT type and will be returned. This happens when we convert DISTINCT to
GROUP BY.

The solution is to take into account the number of such hidden fields that would be added to the field
JOIN::all_fields list while calculating the size of the ref_pointer_array.
2018-05-16 11:40:11 +05:30

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/*
Copyright (c) 2000, 2010, Oracle and/or its affiliates.
Copyright (c) 2010, 2015, MariaDB
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 St, Fifth Floor, Boston, MA 02110-1301 USA */
/*
Delete of records tables.
Multi-table deletes were introduced by Monty and Sinisa
*/
#include <my_global.h>
#include "sql_priv.h"
#include "unireg.h"
#include "sql_delete.h"
#include "sql_cache.h" // query_cache_*
#include "sql_base.h" // open_temprary_table
#include "lock.h" // unlock_table_name
#include "sql_view.h" // check_key_in_view, mysql_frm_type
#include "sql_parse.h" // mysql_init_select
#include "sql_acl.h" // *_ACL
#include "filesort.h" // filesort
#include "sql_handler.h" // mysql_ha_rm_tables
#include "sql_select.h"
#include "sp_head.h"
#include "sql_trigger.h"
#include "sql_statistics.h"
#include "transaction.h"
#include "records.h" // init_read_record,
#include "filesort.h"
#include "uniques.h"
#include "sql_derived.h" // mysql_handle_list_of_derived
// end_read_record
#include "sql_partition.h" // make_used_partitions_str
/*
@brief
Print query plan of a single-table DELETE command
@detail
This function is used by EXPLAIN DELETE and by SHOW EXPLAIN when it is
invoked on a running DELETE statement.
*/
Explain_delete* Delete_plan::save_explain_delete_data(MEM_ROOT *mem_root, THD *thd)
{
Explain_query *query= thd->lex->explain;
Explain_delete *explain=
new (mem_root) Explain_delete(mem_root, thd->lex->analyze_stmt);
if (deleting_all_rows)
{
explain->deleting_all_rows= true;
explain->select_type= "SIMPLE";
explain->rows= scanned_rows;
}
else
{
explain->deleting_all_rows= false;
Update_plan::save_explain_data_intern(mem_root, explain,
thd->lex->analyze_stmt);
}
query->add_upd_del_plan(explain);
return explain;
}
Explain_update*
Update_plan::save_explain_update_data(MEM_ROOT *mem_root, THD *thd)
{
Explain_query *query= thd->lex->explain;
Explain_update* explain=
new (mem_root) Explain_update(mem_root, thd->lex->analyze_stmt);
save_explain_data_intern(mem_root, explain, thd->lex->analyze_stmt);
query->add_upd_del_plan(explain);
return explain;
}
void Update_plan::save_explain_data_intern(MEM_ROOT *mem_root,
Explain_update *explain,
bool is_analyze)
{
explain->select_type= "SIMPLE";
explain->table_name.append(table->pos_in_table_list->alias);
explain->impossible_where= false;
explain->no_partitions= false;
if (impossible_where)
{
explain->impossible_where= true;
return;
}
if (no_partitions)
{
explain->no_partitions= true;
return;
}
if (is_analyze)
table->file->set_time_tracker(&explain->table_tracker);
select_lex->set_explain_type(TRUE);
explain->select_type= select_lex->type;
/* Partitions */
{
#ifdef WITH_PARTITION_STORAGE_ENGINE
partition_info *part_info;
if ((part_info= table->part_info))
{
make_used_partitions_str(mem_root, part_info, &explain->used_partitions,
explain->used_partitions_list);
explain->used_partitions_set= true;
}
else
explain->used_partitions_set= false;
#else
/* just produce empty column if partitioning is not compiled in */
explain->used_partitions_set= false;
#endif
}
/* Set jtype */
if (select && select->quick)
{
int quick_type= select->quick->get_type();
if ((quick_type == QUICK_SELECT_I::QS_TYPE_INDEX_MERGE) ||
(quick_type == QUICK_SELECT_I::QS_TYPE_INDEX_INTERSECT) ||
(quick_type == QUICK_SELECT_I::QS_TYPE_ROR_INTERSECT) ||
(quick_type == QUICK_SELECT_I::QS_TYPE_ROR_UNION))
explain->jtype= JT_INDEX_MERGE;
else
explain->jtype= JT_RANGE;
}
else
{
if (index == MAX_KEY)
explain->jtype= JT_ALL;
else
explain->jtype= JT_NEXT;
}
explain->using_where= MY_TEST(select && select->cond);
explain->where_cond= select? select->cond: NULL;
if (using_filesort)
explain->filesort_tracker= new (mem_root) Filesort_tracker(is_analyze);
explain->using_io_buffer= using_io_buffer;
append_possible_keys(mem_root, explain->possible_keys, table,
possible_keys);
explain->quick_info= NULL;
/* Calculate key_len */
if (select && select->quick)
{
explain->quick_info= select->quick->get_explain(mem_root);
}
else
{
if (index != MAX_KEY)
{
explain->key.set(mem_root, &table->key_info[index],
table->key_info[index].key_length);
}
}
explain->rows= scanned_rows;
if (select && select->quick &&
select->quick->get_type() == QUICK_SELECT_I::QS_TYPE_RANGE)
{
explain_append_mrr_info((QUICK_RANGE_SELECT*)select->quick,
&explain->mrr_type);
}
bool skip= updating_a_view;
/* Save subquery children */
for (SELECT_LEX_UNIT *unit= select_lex->first_inner_unit();
unit;
unit= unit->next_unit())
{
if (skip)
{
skip= false;
continue;
}
/*
Display subqueries only if they are not parts of eliminated WHERE/ON
clauses.
*/
if (!(unit->item && unit->item->eliminated))
explain->add_child(unit->first_select()->select_number);
}
}
/**
Implement DELETE SQL word.
@note Like implementations of other DDL/DML in MySQL, this function
relies on the caller to close the thread tables. This is done in the
end of dispatch_command().
*/
bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
SQL_I_List<ORDER> *order_list, ha_rows limit,
ulonglong options, select_result *result)
{
bool will_batch;
int error, loc_error;
TABLE *table;
SQL_SELECT *select=0;
SORT_INFO *file_sort= 0;
READ_RECORD info;
bool using_limit=limit != HA_POS_ERROR;
bool transactional_table, safe_update, const_cond;
bool const_cond_result;
bool return_error= 0;
ha_rows deleted= 0;
bool reverse= FALSE;
ORDER *order= (ORDER *) ((order_list && order_list->elements) ?
order_list->first : NULL);
SELECT_LEX *select_lex= &thd->lex->select_lex;
killed_state killed_status= NOT_KILLED;
THD::enum_binlog_query_type query_type= THD::ROW_QUERY_TYPE;
bool with_select= !select_lex->item_list.is_empty();
Explain_delete *explain;
Delete_plan query_plan(thd->mem_root);
query_plan.index= MAX_KEY;
query_plan.using_filesort= FALSE;
DBUG_ENTER("mysql_delete");
create_explain_query(thd->lex, thd->mem_root);
if (open_and_lock_tables(thd, table_list, TRUE, 0))
DBUG_RETURN(TRUE);
if (mysql_handle_list_of_derived(thd->lex, table_list, DT_MERGE_FOR_INSERT))
DBUG_RETURN(TRUE);
if (mysql_handle_list_of_derived(thd->lex, table_list, DT_PREPARE))
DBUG_RETURN(TRUE);
if (!table_list->single_table_updatable())
{
my_error(ER_NON_UPDATABLE_TABLE, MYF(0), table_list->alias, "DELETE");
DBUG_RETURN(TRUE);
}
if (!(table= table_list->table) || !table->is_created())
{
my_error(ER_VIEW_DELETE_MERGE_VIEW, MYF(0),
table_list->view_db.str, table_list->view_name.str);
DBUG_RETURN(TRUE);
}
THD_STAGE_INFO(thd, stage_init);
table->map=1;
query_plan.select_lex= &thd->lex->select_lex;
query_plan.table= table;
query_plan.updating_a_view= MY_TEST(table_list->view);
if (mysql_prepare_delete(thd, table_list, select_lex->with_wild,
select_lex->item_list, &conds))
DBUG_RETURN(TRUE);
if (with_select)
(void) result->prepare(select_lex->item_list, NULL);
if (thd->lex->current_select->first_cond_optimization)
{
thd->lex->current_select->save_leaf_tables(thd);
thd->lex->current_select->first_cond_optimization= 0;
}
/* check ORDER BY even if it can be ignored */
if (order)
{
TABLE_LIST tables;
List<Item> fields;
List<Item> all_fields;
bzero((char*) &tables,sizeof(tables));
tables.table = table;
tables.alias = table_list->alias;
if (select_lex->setup_ref_array(thd, order_list->elements) ||
setup_order(thd, select_lex->ref_pointer_array, &tables,
fields, all_fields, order))
{
free_underlaid_joins(thd, &thd->lex->select_lex);
DBUG_RETURN(TRUE);
}
}
/* Apply the IN=>EXISTS transformation to all subqueries and optimize them. */
if (select_lex->optimize_unflattened_subqueries(false))
DBUG_RETURN(TRUE);
const_cond= (!conds || conds->const_item());
safe_update= MY_TEST(thd->variables.option_bits & OPTION_SAFE_UPDATES);
if (safe_update && const_cond)
{
my_message(ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE,
ER_THD(thd, ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE), MYF(0));
DBUG_RETURN(TRUE);
}
const_cond_result= const_cond && (!conds || conds->val_int());
if (thd->is_error())
{
/* Error evaluating val_int(). */
DBUG_RETURN(TRUE);
}
/*
Test if the user wants to delete all rows and deletion doesn't have
any side-effects (because of triggers), so we can use optimized
handler::delete_all_rows() method.
We can use delete_all_rows() if and only if:
- We allow new functions (not using option --skip-new), and are
not in safe mode (not using option --safe-mode)
- There is no limit clause
- The condition is constant
- If there is a condition, then it it produces a non-zero value
- If the current command is DELETE FROM with no where clause, then:
- We should not be binlogging this statement in row-based, and
- there should be no delete triggers associated with the table.
*/
if (!with_select && !using_limit && const_cond_result &&
(!thd->is_current_stmt_binlog_format_row() &&
!(table->triggers && table->triggers->has_delete_triggers())))
{
/* Update the table->file->stats.records number */
table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);
ha_rows const maybe_deleted= table->file->stats.records;
DBUG_PRINT("debug", ("Trying to use delete_all_rows()"));
query_plan.set_delete_all_rows(maybe_deleted);
if (thd->lex->describe)
goto produce_explain_and_leave;
if (!(error=table->file->ha_delete_all_rows()))
{
/*
If delete_all_rows() is used, it is not possible to log the
query in row format, so we have to log it in statement format.
*/
query_type= THD::STMT_QUERY_TYPE;
error= -1;
deleted= maybe_deleted;
query_plan.save_explain_delete_data(thd->mem_root, thd);
goto cleanup;
}
if (error != HA_ERR_WRONG_COMMAND)
{
table->file->print_error(error,MYF(0));
error=0;
goto cleanup;
}
/* Handler didn't support fast delete; Delete rows one by one */
query_plan.cancel_delete_all_rows();
}
if (conds)
{
Item::cond_result result;
conds= conds->remove_eq_conds(thd, &result, true);
if (result == Item::COND_FALSE) // Impossible where
{
limit= 0;
query_plan.set_impossible_where();
if (thd->lex->describe || thd->lex->analyze_stmt)
goto produce_explain_and_leave;
}
}
#ifdef WITH_PARTITION_STORAGE_ENGINE
if (prune_partitions(thd, table, conds))
{
free_underlaid_joins(thd, select_lex);
query_plan.set_no_partitions();
if (thd->lex->describe || thd->lex->analyze_stmt)
goto produce_explain_and_leave;
my_ok(thd, 0);
DBUG_RETURN(0);
}
#endif
/* Update the table->file->stats.records number */
table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);
set_statistics_for_table(thd, table);
table->covering_keys.clear_all();
table->quick_keys.clear_all(); // Can't use 'only index'
select=make_select(table, 0, 0, conds, (SORT_INFO*) 0, 0, &error);
if (error)
DBUG_RETURN(TRUE);
if ((select && select->check_quick(thd, safe_update, limit)) || !limit)
{
query_plan.set_impossible_where();
if (thd->lex->describe || thd->lex->analyze_stmt)
goto produce_explain_and_leave;
delete select;
free_underlaid_joins(thd, select_lex);
/*
Error was already created by quick select evaluation (check_quick()).
TODO: Add error code output parameter to Item::val_xxx() methods.
Currently they rely on the user checking DA for
errors when unwinding the stack after calling Item::val_xxx().
*/
if (thd->is_error())
DBUG_RETURN(TRUE);
my_ok(thd, 0);
DBUG_RETURN(0); // Nothing to delete
}
/* If running in safe sql mode, don't allow updates without keys */
if (table->quick_keys.is_clear_all())
{
thd->set_status_no_index_used();
if (safe_update && !using_limit)
{
delete select;
free_underlaid_joins(thd, select_lex);
my_message(ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE,
ER_THD(thd, ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE), MYF(0));
DBUG_RETURN(TRUE);
}
}
if (options & OPTION_QUICK)
(void) table->file->extra(HA_EXTRA_QUICK);
query_plan.scanned_rows= select? select->records: table->file->stats.records;
if (order)
{
table->update_const_key_parts(conds);
order= simple_remove_const(order, conds);
if (select && select->quick && select->quick->unique_key_range())
{ // Single row select (always "ordered")
query_plan.using_filesort= FALSE;
query_plan.index= MAX_KEY;
}
else
{
ha_rows scanned_limit= query_plan.scanned_rows;
query_plan.index= get_index_for_order(order, table, select, limit,
&scanned_limit,
&query_plan.using_filesort,
&reverse);
if (!query_plan.using_filesort)
query_plan.scanned_rows= scanned_limit;
}
}
query_plan.select= select;
query_plan.possible_keys= select? select->possible_keys: key_map(0);
/*
Ok, we have generated a query plan for the DELETE.
- if we're running EXPLAIN DELETE, goto produce explain output
- otherwise, execute the query plan
*/
if (thd->lex->describe)
goto produce_explain_and_leave;
explain= query_plan.save_explain_delete_data(thd->mem_root, thd);
ANALYZE_START_TRACKING(&explain->command_tracker);
DBUG_EXECUTE_IF("show_explain_probe_delete_exec_start",
dbug_serve_apcs(thd, 1););
if (!(select && select->quick))
status_var_increment(thd->status_var.delete_scan_count);
if (query_plan.using_filesort)
{
{
Filesort fsort(order, HA_POS_ERROR, true, select);
DBUG_ASSERT(query_plan.index == MAX_KEY);
Filesort_tracker *fs_tracker=
thd->lex->explain->get_upd_del_plan()->filesort_tracker;
if (!(file_sort= filesort(thd, table, &fsort, fs_tracker)))
goto got_error;
thd->inc_examined_row_count(file_sort->examined_rows);
/*
Filesort has already found and selected the rows we want to delete,
so we don't need the where clause
*/
delete select;
/*
If we are not in DELETE ... RETURNING, we can free subqueries. (in
DELETE ... RETURNING we can't, because the RETURNING part may have
a subquery in it)
*/
if (!with_select)
free_underlaid_joins(thd, select_lex);
select= 0;
}
}
/* If quick select is used, initialize it before retrieving rows. */
if (select && select->quick && select->quick->reset())
goto got_error;
if (query_plan.index == MAX_KEY || (select && select->quick))
error= init_read_record(&info, thd, table, select, file_sort, 1, 1, FALSE);
else
error= init_read_record_idx(&info, thd, table, 1, query_plan.index,
reverse);
if (error)
goto got_error;
init_ftfuncs(thd, select_lex, 1);
THD_STAGE_INFO(thd, stage_updating);
if (table->prepare_triggers_for_delete_stmt_or_event())
{
will_batch= FALSE;
}
else
will_batch= !table->file->start_bulk_delete();
table->mark_columns_needed_for_delete();
if (with_select)
{
if (result->send_result_set_metadata(select_lex->item_list,
Protocol::SEND_NUM_ROWS |
Protocol::SEND_EOF))
goto cleanup;
}
explain= (Explain_delete*)thd->lex->explain->get_upd_del_plan();
explain->tracker.on_scan_init();
while (!(error=info.read_record(&info)) && !thd->killed &&
! thd->is_error())
{
explain->tracker.on_record_read();
thd->inc_examined_row_count(1);
if (table->vfield)
(void) table->update_virtual_fields(table->file, VCOL_UPDATE_FOR_DELETE);
if (!select || select->skip_record(thd) > 0)
{
explain->tracker.on_record_after_where();
if (table->triggers &&
table->triggers->process_triggers(thd, TRG_EVENT_DELETE,
TRG_ACTION_BEFORE, FALSE))
{
error= 1;
break;
}
if (with_select && result->send_data(select_lex->item_list) < 0)
{
error=1;
break;
}
if (!(error= table->file->ha_delete_row(table->record[0])))
{
deleted++;
if (table->triggers &&
table->triggers->process_triggers(thd, TRG_EVENT_DELETE,
TRG_ACTION_AFTER, FALSE))
{
error= 1;
break;
}
if (!--limit && using_limit)
{
error= -1;
break;
}
}
else
{
table->file->print_error(error,
MYF(thd->lex->ignore ? ME_JUST_WARNING : 0));
if (thd->is_error())
{
error= 1;
break;
}
}
}
/*
Don't try unlocking the row if skip_record reported an error since in
this case the transaction might have been rolled back already.
*/
else if (!thd->is_error())
table->file->unlock_row(); // Row failed selection, release lock on it
else
break;
}
killed_status= thd->killed;
if (killed_status != NOT_KILLED || thd->is_error())
error= 1; // Aborted
if (will_batch && (loc_error= table->file->end_bulk_delete()))
{
if (error != 1)
table->file->print_error(loc_error,MYF(0));
error=1;
}
THD_STAGE_INFO(thd, stage_end);
end_read_record(&info);
if (options & OPTION_QUICK)
(void) table->file->extra(HA_EXTRA_NORMAL);
ANALYZE_STOP_TRACKING(&explain->command_tracker);
cleanup:
/*
Invalidate the table in the query cache if something changed. This must
be before binlog writing and ha_autocommit_...
*/
if (deleted)
{
query_cache_invalidate3(thd, table_list, 1);
}
if (thd->lex->current_select->first_cond_optimization)
{
thd->lex->current_select->save_leaf_tables(thd);
thd->lex->current_select->first_cond_optimization= 0;
}
delete select;
select= NULL;
transactional_table= table->file->has_transactions();
if (!transactional_table && deleted > 0)
thd->transaction.stmt.modified_non_trans_table=
thd->transaction.all.modified_non_trans_table= TRUE;
/* See similar binlogging code in sql_update.cc, for comments */
if ((error < 0) || thd->transaction.stmt.modified_non_trans_table)
{
if (WSREP_EMULATE_BINLOG(thd) || mysql_bin_log.is_open())
{
int errcode= 0;
if (error < 0)
thd->clear_error();
else
errcode= query_error_code(thd, killed_status == NOT_KILLED);
/*
[binlog]: If 'handler::delete_all_rows()' was called and the
storage engine does not inject the rows itself, we replicate
statement-based; otherwise, 'ha_delete_row()' was used to
delete specific rows which we might log row-based.
*/
int log_result= thd->binlog_query(query_type,
thd->query(), thd->query_length(),
transactional_table, FALSE, FALSE,
errcode);
if (log_result)
{
error=1;
}
}
}
DBUG_ASSERT(transactional_table || !deleted || thd->transaction.stmt.modified_non_trans_table);
if (error < 0 ||
(thd->lex->ignore && !thd->is_error() && !thd->is_fatal_error))
{
if (thd->lex->analyze_stmt)
goto send_nothing_and_leave;
if (with_select)
result->send_eof();
else
my_ok(thd, deleted);
DBUG_PRINT("info",("%ld records deleted",(long) deleted));
}
delete file_sort;
free_underlaid_joins(thd, select_lex);
DBUG_RETURN(error >= 0 || thd->is_error());
/* Special exits */
produce_explain_and_leave:
/*
We come here for various "degenerate" query plans: impossible WHERE,
no-partitions-used, impossible-range, etc.
*/
query_plan.save_explain_delete_data(thd->mem_root, thd);
send_nothing_and_leave:
/*
ANALYZE DELETE jumps here. We can't send explain right here, because
we might be using ANALYZE DELETE ...RETURNING, in which case we have
Protocol_discard active.
*/
delete select;
delete file_sort;
free_underlaid_joins(thd, select_lex);
//table->set_keyread(false);
DBUG_ASSERT(!return_error || thd->is_error() || thd->killed);
DBUG_RETURN((return_error || thd->is_error() || thd->killed) ? 1 : 0);
got_error:
return_error= 1;
goto send_nothing_and_leave;
}
/*
Prepare items in DELETE statement
SYNOPSIS
mysql_prepare_delete()
thd - thread handler
table_list - global/local table list
wild_num - number of wildcards used in optional SELECT clause
field_list - list of items in optional SELECT clause
conds - conditions
l
RETURN VALUE
FALSE OK
TRUE error
*/
int mysql_prepare_delete(THD *thd, TABLE_LIST *table_list,
uint wild_num, List<Item> &field_list, Item **conds)
{
Item *fake_conds= 0;
SELECT_LEX *select_lex= &thd->lex->select_lex;
DBUG_ENTER("mysql_prepare_delete");
List<Item> all_fields;
thd->lex->allow_sum_func= 0;
if (setup_tables_and_check_access(thd, &thd->lex->select_lex.context,
&thd->lex->select_lex.top_join_list,
table_list,
select_lex->leaf_tables, FALSE,
DELETE_ACL, SELECT_ACL, TRUE))
DBUG_RETURN(TRUE);
if ((wild_num && setup_wild(thd, table_list, field_list, NULL, wild_num,
&select_lex->hidden_bit_fields)) ||
setup_fields(thd, Ref_ptr_array(),
field_list, MARK_COLUMNS_READ, NULL, NULL, 0) ||
setup_conds(thd, table_list, select_lex->leaf_tables, conds) ||
setup_ftfuncs(select_lex))
DBUG_RETURN(TRUE);
if (!table_list->single_table_updatable() ||
check_key_in_view(thd, table_list))
{
my_error(ER_NON_UPDATABLE_TABLE, MYF(0), table_list->alias, "DELETE");
DBUG_RETURN(TRUE);
}
{
TABLE_LIST *duplicate;
if ((duplicate= unique_table(thd, table_list, table_list->next_global, 0)))
{
update_non_unique_table_error(table_list, "DELETE", duplicate);
DBUG_RETURN(TRUE);
}
}
if (select_lex->inner_refs_list.elements &&
fix_inner_refs(thd, all_fields, select_lex, select_lex->ref_pointer_array))
DBUG_RETURN(TRUE);
select_lex->fix_prepare_information(thd, conds, &fake_conds);
DBUG_RETURN(FALSE);
}
/***************************************************************************
Delete multiple tables from join
***************************************************************************/
#define MEM_STRIP_BUF_SIZE (size_t)(current_thd->variables.sortbuff_size)
extern "C" int refpos_order_cmp(void* arg, const void *a,const void *b)
{
handler *file= (handler*)arg;
return file->cmp_ref((const uchar*)a, (const uchar*)b);
}
/*
make delete specific preparation and checks after opening tables
SYNOPSIS
mysql_multi_delete_prepare()
thd thread handler
RETURN
FALSE OK
TRUE Error
*/
int mysql_multi_delete_prepare(THD *thd)
{
LEX *lex= thd->lex;
TABLE_LIST *aux_tables= lex->auxiliary_table_list.first;
TABLE_LIST *target_tbl;
DBUG_ENTER("mysql_multi_delete_prepare");
if (mysql_handle_derived(lex, DT_INIT))
DBUG_RETURN(TRUE);
if (mysql_handle_derived(lex, DT_MERGE_FOR_INSERT))
DBUG_RETURN(TRUE);
if (mysql_handle_derived(lex, DT_PREPARE))
DBUG_RETURN(TRUE);
/*
setup_tables() need for VIEWs. JOIN::prepare() will not do it second
time.
lex->query_tables also point on local list of DELETE SELECT_LEX
*/
if (setup_tables_and_check_access(thd, &thd->lex->select_lex.context,
&thd->lex->select_lex.top_join_list,
lex->query_tables,
lex->select_lex.leaf_tables, FALSE,
DELETE_ACL, SELECT_ACL, FALSE))
DBUG_RETURN(TRUE);
if (lex->select_lex.handle_derived(thd->lex, DT_MERGE))
DBUG_RETURN(TRUE);
/*
Multi-delete can't be constructed over-union => we always have
single SELECT on top and have to check underlying SELECTs of it
*/
lex->select_lex.exclude_from_table_unique_test= TRUE;
/* Fix tables-to-be-deleted-from list to point at opened tables */
for (target_tbl= (TABLE_LIST*) aux_tables;
target_tbl;
target_tbl= target_tbl->next_local)
{
target_tbl->table= target_tbl->correspondent_table->table;
if (target_tbl->correspondent_table->is_multitable())
{
my_error(ER_VIEW_DELETE_MERGE_VIEW, MYF(0),
target_tbl->correspondent_table->view_db.str,
target_tbl->correspondent_table->view_name.str);
DBUG_RETURN(TRUE);
}
if (!target_tbl->correspondent_table->single_table_updatable() ||
check_key_in_view(thd, target_tbl->correspondent_table))
{
my_error(ER_NON_UPDATABLE_TABLE, MYF(0),
target_tbl->table_name, "DELETE");
DBUG_RETURN(TRUE);
}
/*
Check that table from which we delete is not used somewhere
inside subqueries/view.
*/
{
TABLE_LIST *duplicate;
if ((duplicate= unique_table(thd, target_tbl->correspondent_table,
lex->query_tables, 0)))
{
update_non_unique_table_error(target_tbl->correspondent_table,
"DELETE", duplicate);
DBUG_RETURN(TRUE);
}
}
}
/*
Reset the exclude flag to false so it doesn't interfare
with further calls to unique_table
*/
lex->select_lex.exclude_from_table_unique_test= FALSE;
if (lex->save_prep_leaf_tables())
DBUG_RETURN(TRUE);
DBUG_RETURN(FALSE);
}
multi_delete::multi_delete(THD *thd_arg, TABLE_LIST *dt, uint num_of_tables_arg):
select_result_interceptor(thd_arg), delete_tables(dt), deleted(0), found(0),
num_of_tables(num_of_tables_arg), error(0),
do_delete(0), transactional_tables(0), normal_tables(0), error_handled(0)
{
tempfiles= (Unique **) thd_arg->calloc(sizeof(Unique *) * num_of_tables);
}
int
multi_delete::prepare(List<Item> &values, SELECT_LEX_UNIT *u)
{
DBUG_ENTER("multi_delete::prepare");
unit= u;
do_delete= 1;
THD_STAGE_INFO(thd, stage_deleting_from_main_table);
SELECT_LEX *select_lex= u->first_select();
if (select_lex->first_cond_optimization)
{
if (select_lex->handle_derived(thd->lex, DT_MERGE))
DBUG_RETURN(TRUE);
}
DBUG_RETURN(0);
}
void multi_delete::prepare_to_read_rows()
{
/* see multi_update::prepare_to_read_rows() */
for (TABLE_LIST *walk= delete_tables; walk; walk= walk->next_local)
{
TABLE_LIST *tbl= walk->correspondent_table->find_table_for_update();
tbl->table->mark_columns_needed_for_delete();
}
}
bool
multi_delete::initialize_tables(JOIN *join)
{
TABLE_LIST *walk;
Unique **tempfiles_ptr;
DBUG_ENTER("initialize_tables");
if ((thd->variables.option_bits & OPTION_SAFE_UPDATES) && error_if_full_join(join))
DBUG_RETURN(1);
table_map tables_to_delete_from=0;
delete_while_scanning= 1;
for (walk= delete_tables; walk; walk= walk->next_local)
{
TABLE_LIST *tbl= walk->correspondent_table->find_table_for_update();
tables_to_delete_from|= tbl->table->map;
if (delete_while_scanning &&
unique_table(thd, tbl, join->tables_list, false))
{
/*
If the table we are going to delete from appears
in join, we need to defer delete. So the delete
doesn't interfers with the scaning of results.
*/
delete_while_scanning= 0;
}
}
walk= delete_tables;
for (JOIN_TAB *tab= first_linear_tab(join, WITHOUT_BUSH_ROOTS,
WITH_CONST_TABLES);
tab;
tab= next_linear_tab(join, tab, WITHOUT_BUSH_ROOTS))
{
if (!tab->bush_children && tab->table->map & tables_to_delete_from)
{
/* We are going to delete from this table */
TABLE *tbl=walk->table=tab->table;
walk= walk->next_local;
/* Don't use KEYREAD optimization on this table */
tbl->no_keyread=1;
/* Don't use record cache */
tbl->no_cache= 1;
tbl->covering_keys.clear_all();
if (tbl->file->has_transactions())
transactional_tables= 1;
else
normal_tables= 1;
tbl->prepare_triggers_for_delete_stmt_or_event();
tbl->prepare_for_position();
}
else if ((tab->type != JT_SYSTEM && tab->type != JT_CONST) &&
walk == delete_tables)
{
/*
We are not deleting from the table we are scanning. In this
case send_data() shouldn't delete any rows a we may touch
the rows in the deleted table many times
*/
delete_while_scanning= 0;
}
}
walk= delete_tables;
tempfiles_ptr= tempfiles;
if (delete_while_scanning)
{
table_being_deleted= delete_tables;
walk= walk->next_local;
}
for (;walk ;walk= walk->next_local)
{
TABLE *table=walk->table;
*tempfiles_ptr++= new Unique (refpos_order_cmp,
(void *) table->file,
table->file->ref_length,
MEM_STRIP_BUF_SIZE);
}
init_ftfuncs(thd, thd->lex->current_select, 1);
DBUG_RETURN(thd->is_fatal_error != 0);
}
multi_delete::~multi_delete()
{
for (table_being_deleted= delete_tables;
table_being_deleted;
table_being_deleted= table_being_deleted->next_local)
{
TABLE *table= table_being_deleted->table;
table->no_keyread=0;
}
for (uint counter= 0; counter < num_of_tables; counter++)
{
if (tempfiles[counter])
delete tempfiles[counter];
}
}
int multi_delete::send_data(List<Item> &values)
{
int secure_counter= delete_while_scanning ? -1 : 0;
TABLE_LIST *del_table;
DBUG_ENTER("multi_delete::send_data");
bool ignore= thd->lex->ignore;
for (del_table= delete_tables;
del_table;
del_table= del_table->next_local, secure_counter++)
{
TABLE *table= del_table->table;
/* Check if we are using outer join and we didn't find the row */
if (table->status & (STATUS_NULL_ROW | STATUS_DELETED))
continue;
table->file->position(table->record[0]);
found++;
if (secure_counter < 0)
{
/* We are scanning the current table */
DBUG_ASSERT(del_table == table_being_deleted);
if (table->triggers &&
table->triggers->process_triggers(thd, TRG_EVENT_DELETE,
TRG_ACTION_BEFORE, FALSE))
DBUG_RETURN(1);
table->status|= STATUS_DELETED;
if (!(error=table->file->ha_delete_row(table->record[0])))
{
deleted++;
if (!table->file->has_transactions())
thd->transaction.stmt.modified_non_trans_table= TRUE;
if (table->triggers &&
table->triggers->process_triggers(thd, TRG_EVENT_DELETE,
TRG_ACTION_AFTER, FALSE))
DBUG_RETURN(1);
}
else if (!ignore)
{
/*
If the IGNORE option is used errors caused by ha_delete_row don't
have to stop the iteration.
*/
table->file->print_error(error,MYF(0));
DBUG_RETURN(1);
}
}
else
{
error=tempfiles[secure_counter]->unique_add((char*) table->file->ref);
if (error)
{
error= 1; // Fatal error
DBUG_RETURN(1);
}
}
}
DBUG_RETURN(0);
}
void multi_delete::abort_result_set()
{
DBUG_ENTER("multi_delete::abort_result_set");
/* the error was handled or nothing deleted and no side effects return */
if (error_handled ||
(!thd->transaction.stmt.modified_non_trans_table && !deleted))
DBUG_VOID_RETURN;
/* Something already deleted so we have to invalidate cache */
if (deleted)
query_cache_invalidate3(thd, delete_tables, 1);
if (thd->transaction.stmt.modified_non_trans_table)
thd->transaction.all.modified_non_trans_table= TRUE;
thd->transaction.all.m_unsafe_rollback_flags|=
(thd->transaction.stmt.m_unsafe_rollback_flags & THD_TRANS::DID_WAIT);
/*
If rows from the first table only has been deleted and it is
transactional, just do rollback.
The same if all tables are transactional, regardless of where we are.
In all other cases do attempt deletes ...
*/
if (do_delete && normal_tables &&
(table_being_deleted != delete_tables ||
!table_being_deleted->table->file->has_transactions()))
{
/*
We have to execute the recorded do_deletes() and write info into the
error log
*/
error= 1;
send_eof();
DBUG_ASSERT(error_handled);
DBUG_VOID_RETURN;
}
if (thd->transaction.stmt.modified_non_trans_table)
{
/*
there is only side effects; to binlog with the error
*/
if (WSREP_EMULATE_BINLOG(thd) || mysql_bin_log.is_open())
{
int errcode= query_error_code(thd, thd->killed == NOT_KILLED);
/* possible error of writing binary log is ignored deliberately */
(void) thd->binlog_query(THD::ROW_QUERY_TYPE,
thd->query(), thd->query_length(),
transactional_tables, FALSE, FALSE, errcode);
}
}
DBUG_VOID_RETURN;
}
/**
Do delete from other tables.
@retval 0 ok
@retval 1 error
@todo Is there any reason not use the normal nested-loops join? If not, and
there is no documentation supporting it, this method and callee should be
removed and there should be hooks within normal execution.
*/
int multi_delete::do_deletes()
{
DBUG_ENTER("do_deletes");
DBUG_ASSERT(do_delete);
do_delete= 0; // Mark called
if (!found)
DBUG_RETURN(0);
table_being_deleted= (delete_while_scanning ? delete_tables->next_local :
delete_tables);
for (uint counter= 0; table_being_deleted;
table_being_deleted= table_being_deleted->next_local, counter++)
{
TABLE *table = table_being_deleted->table;
int local_error;
if (tempfiles[counter]->get(table))
DBUG_RETURN(1);
local_error= do_table_deletes(table, &tempfiles[counter]->sort,
thd->lex->ignore);
if (thd->killed && !local_error)
DBUG_RETURN(1);
if (local_error == -1) // End of file
local_error = 0;
if (local_error)
DBUG_RETURN(local_error);
}
DBUG_RETURN(0);
}
/**
Implements the inner loop of nested-loops join within multi-DELETE
execution.
@param table The table from which to delete.
@param ignore If used, all non fatal errors will be translated
to warnings and we should not break the row-by-row iteration.
@return Status code
@retval 0 All ok.
@retval 1 Triggers or handler reported error.
@retval -1 End of file from handler.
*/
int multi_delete::do_table_deletes(TABLE *table, SORT_INFO *sort_info,
bool ignore)
{
int local_error= 0;
READ_RECORD info;
ha_rows last_deleted= deleted;
DBUG_ENTER("do_deletes_for_table");
if (init_read_record(&info, thd, table, NULL, sort_info, 0, 1, FALSE))
DBUG_RETURN(1);
/*
Ignore any rows not found in reference tables as they may already have
been deleted by foreign key handling
*/
info.ignore_not_found_rows= 1;
bool will_batch= !table->file->start_bulk_delete();
while (!(local_error= info.read_record(&info)) && !thd->killed)
{
if (table->triggers &&
table->triggers->process_triggers(thd, TRG_EVENT_DELETE,
TRG_ACTION_BEFORE, FALSE))
{
local_error= 1;
break;
}
local_error= table->file->ha_delete_row(table->record[0]);
if (local_error && !ignore)
{
table->file->print_error(local_error, MYF(0));
break;
}
/*
Increase the reported number of deleted rows only if no error occurred
during ha_delete_row.
Also, don't execute the AFTER trigger if the row operation failed.
*/
if (!local_error)
{
deleted++;
if (table->triggers &&
table->triggers->process_triggers(thd, TRG_EVENT_DELETE,
TRG_ACTION_AFTER, FALSE))
{
local_error= 1;
break;
}
}
}
if (will_batch)
{
int tmp_error= table->file->end_bulk_delete();
if (tmp_error && !local_error)
{
local_error= tmp_error;
table->file->print_error(local_error, MYF(0));
}
}
if (last_deleted != deleted && !table->file->has_transactions())
thd->transaction.stmt.modified_non_trans_table= TRUE;
end_read_record(&info);
DBUG_RETURN(local_error);
}
/*
Send ok to the client
return: 0 sucess
1 error
*/
bool multi_delete::send_eof()
{
killed_state killed_status= NOT_KILLED;
THD_STAGE_INFO(thd, stage_deleting_from_reference_tables);
/* Does deletes for the last n - 1 tables, returns 0 if ok */
int local_error= do_deletes(); // returns 0 if success
/* compute a total error to know if something failed */
local_error= local_error || error;
killed_status= (local_error == 0)? NOT_KILLED : thd->killed;
/* reset used flags */
THD_STAGE_INFO(thd, stage_end);
if (thd->transaction.stmt.modified_non_trans_table)
thd->transaction.all.modified_non_trans_table= TRUE;
thd->transaction.all.m_unsafe_rollback_flags|=
(thd->transaction.stmt.m_unsafe_rollback_flags & THD_TRANS::DID_WAIT);
/*
We must invalidate the query cache before binlog writing and
ha_autocommit_...
*/
if (deleted)
{
query_cache_invalidate3(thd, delete_tables, 1);
}
if ((local_error == 0) || thd->transaction.stmt.modified_non_trans_table)
{
if(WSREP_EMULATE_BINLOG(thd) || mysql_bin_log.is_open())
{
int errcode= 0;
if (local_error == 0)
thd->clear_error();
else
errcode= query_error_code(thd, killed_status == NOT_KILLED);
if (thd->binlog_query(THD::ROW_QUERY_TYPE,
thd->query(), thd->query_length(),
transactional_tables, FALSE, FALSE, errcode) &&
!normal_tables)
{
local_error=1; // Log write failed: roll back the SQL statement
}
}
}
if (local_error != 0)
error_handled= TRUE; // to force early leave from ::abort_result_set()
if (!local_error && !thd->lex->analyze_stmt)
{
::my_ok(thd, deleted);
}
return 0;
}
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