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Fixed that derived tables are properly droped

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This commit is contained in:
monty@mashka.mysql.fi
2003-01-07 11:45:06 +02:00
parent edb019aeaf
commit 22aaac013b
10 changed files with 117 additions and 66 deletions
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101
sql/sql_derived.cc
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@ -1,4 +1,4 @@
/* Copyright (C) 2000 MySQL AB
/* Copyright (C) 2002-2003 MySQL AB
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
@ -17,7 +17,7 @@
/*
Derived tables
These were introduced by Monty and Sinisa <sinisa@mysql.com>
These were introduced by Sinisa <sinisa@mysql.com>
*/
@ -38,17 +38,26 @@ static const char *any_db="*any*"; // Special symbol for check_access
t TABLE_LIST for the upper SELECT
IMPLEMENTATION
Derived table is resolved with temporary table. It is created based on the
queries defined. After temporary table is created, if this is not EXPLAIN,
then the entire unit / node is deleted. unit is deleted if UNION is used
for derived table and node is deleted is it is a simple SELECT.
Derived table is resolved with temporary table. It is created based on the
queries defined. After temporary table is created, if this is not EXPLAIN,
then the entire unit / node is deleted. unit is deleted if UNION is used
for derived table and node is deleted is it is a simple SELECT.
After table creation, the above TABLE_LIST is updated with a new table.
After table creation, the above TABLE_LIST is updated with a new table.
This function is called before any command containing derived table is executed.
This function is called before any command containing derived table
is executed.
TODO: To move creation of derived tables IN open_and_lock_tables()
Derived tables is stored in thd->derived_tables and freed in
close_thread_tables()
TODO
Move creation of derived tables in open_and_lock_tables()
RETURN
0 ok
1 Error
-1 Error and error message given
*/
@ -57,21 +66,21 @@ int mysql_derived(THD *thd, LEX *lex, SELECT_LEX_UNIT *unit, TABLE_LIST *t)
SELECT_LEX *sl= unit->first_select();
List<Item> item_list;
TABLE *table;
int res= 0;
int res;
select_union *derived_result;
TABLE_LIST *tables= (TABLE_LIST *)sl->table_list.first;
TMP_TABLE_PARAM tmp_table_param;
bool is_union=sl->next_select() && sl->next_select()->linkage == UNION_TYPE;
DBUG_ENTER("mysql_derived");
SELECT_LEX_NODE *save_current_select= lex->current_select;
DBUG_ENTER("mysql_derived");
/*
In create_total_list, derived tables have to be treated in case of EXPLAIN,
This is because unit/node is not deleted in that case. Current code in this
function has to be improved to recognize better when this function is called
from derived tables and when from other functions.
*/
/*
In create_total_list, derived tables have to be treated in case of
EXPLAIN, This is because unit/node is not deleted in that
case. Current code in this function has to be improved to
recognize better when this function is called from derived tables
and when from other functions.
*/
if (is_union && unit->create_total_list(thd, lex, &tables))
DBUG_RETURN(-1);
@ -92,30 +101,21 @@ int mysql_derived(THD *thd, LEX *lex, SELECT_LEX_UNIT *unit, TABLE_LIST *t)
{
if (is_union)
{
/*
The following code is a re-do of fix_tables_pointers() found in sql_select.cc
for UNION's within derived tables. The only difference is in navigation, as in
derived tables we care for this level only.
/*
The following code is a re-do of fix_tables_pointers() found
in sql_select.cc for UNION's within derived tables. The only
difference is in navigation, as in derived tables we care for
this level only.
fix_tables_pointers makes sure that in UNION's we do not open single table twice
if found in different SELECT's.
*/
for (SELECT_LEX *sel= sl;
sel;
sel= sel->next_select())
{
for (TABLE_LIST *cursor= (TABLE_LIST *)sel->table_list.first;
cursor;
cursor=cursor->next)
cursor->table= cursor->table_list->table;
}
*/
for (SELECT_LEX *sel= sl; sel; sel= sel->next_select())
relink_tables(sel);
}
lex->current_select= sl;
if (setup_fields(thd,tables,item_list,0,0,1))
{
res=-1;
res= -1;
goto exit;
}
bzero((char*) &tmp_table_param,sizeof(tmp_table_param));
@ -127,7 +127,7 @@ int mysql_derived(THD *thd, LEX *lex, SELECT_LEX_UNIT *unit, TABLE_LIST *t)
TMP_TABLE_ALL_COLUMNS),
HA_POS_ERROR)))
{
res=-1;
res= -1;
goto exit;
}
@ -142,7 +142,7 @@ int mysql_derived(THD *thd, LEX *lex, SELECT_LEX_UNIT *unit, TABLE_LIST *t)
sl->options&= ~OPTION_FOUND_ROWS;
if (is_union)
res=mysql_union(thd,lex,derived_result,unit);
res= mysql_union(thd,lex,derived_result,unit);
else
res= mysql_select(thd, tables, sl->item_list,
sl->where, (ORDER *) sl->order_list.first,
@ -153,9 +153,12 @@ int mysql_derived(THD *thd, LEX *lex, SELECT_LEX_UNIT *unit, TABLE_LIST *t)
if (!res)
{
// Here we entirely fix both TABLE_LIST and list of SELECT's as there were no derived tables
/*
Here we entirely fix both TABLE_LIST and list of SELECT's as
there were no derived tables
*/
if (derived_result->flush())
res=1;
res= 1;
else
{
t->real_name=table->real_name;
@ -164,23 +167,29 @@ int mysql_derived(THD *thd, LEX *lex, SELECT_LEX_UNIT *unit, TABLE_LIST *t)
table->tmp_table=TMP_TABLE;
if (lex->describe)
{
// to fix a problem in EXPLAIN
if (tables)
tables->table_list->table=tables->table; // to fix a problem in EXPLAIN
tables->table_list->table=tables->table;
}
else
unit->exclude();
t->db=(char *)"";
t->derived=(SELECT_LEX *)1; // just in case ...
t->db= (char *)"";
t->derived=(SELECT_LEX *) 1; // just in case ...
table->file->info(HA_STATUS_VARIABLE);
}
}
delete derived_result;
}
if (res)
free_tmp_table(thd,table);
free_tmp_table(thd, table);
else
{
table->next= thd->derived_tables;
thd->derived_tables= table;
}
exit:
lex->current_select= save_current_select;
close_thread_tables(thd);
close_thread_tables(thd, 0, 1);
}
DBUG_RETURN(res);
}