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new method to detect commands where all VIEWs should be temporary tables (BUG#4803)

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mysql-test/r/view.result:
  Showing VIEW with VIEWs in subquery
mysql-test/t/view.test:
  Showing VIEW with VIEWs in subquery
sql/sql_lex.cc:
  new method to detect commands where all VIEWs should be temporary tables
sql/sql_lex.h:
  new method to detect commands where all VIEWs should be temporary tables
sql/sql_view.cc:
  new method to detect commands where all VIEWs should be temporary tables
  debug output added
This commit is contained in:
unknown
2004-08-24 22:51:23 +03:00
parent 52b735a1a2
commit b8785595b9
5 changed files with 49 additions and 2 deletions
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9
mysql-test/r/view.result
View File

@@ -1083,3 +1083,12 @@ count(*)
2
drop view v1;
drop table t1;
create table t1 (a int);
create table t2 (a int);
create view v1 as select a from t1;
create view v2 as select a from t2 where a in (select a from v1);
show create view v2;
Table Create Table
v2 CREATE VIEW test.v2 AS select `test`.`t2`.`a` AS `a` from `test`.`t2` where `a` in (select `v1`.`a` AS `a` from `test`.`v1`)
drop view v2, v1;
drop table t1, t2;

11
mysql-test/t/view.test
View File

@@ -1027,3 +1027,14 @@ insert into t1 values (null);
select * from v1;
drop view v1;
drop table t1;
#
# Showing VIEW with VIEWs in subquery
#
create table t1 (a int);
create table t2 (a int);
create view v1 as select a from t1;
create view v2 as select a from t2 where a in (select a from v1);
show create view v2;
drop view v2, v1;
drop table t1, t2;

25
sql/sql_lex.cc
View File

@@ -1546,7 +1546,7 @@ bool st_lex::can_be_merged()
}
/*
check if command can use VIEW with MERGE algorithm
check if command can use VIEW with MERGE algorithm (for top VIEWs)
SYNOPSIS
st_lex::can_use_merged()
@@ -1576,6 +1576,29 @@ bool st_lex::can_use_merged()
}
}
/*
check if command can't use merged views in any part of command
SYNOPSIS
st_lex::can_not_use_merged()
RETURN
FALSE - command can't use merged VIEWs
TRUE - VIEWs with MERGE algorithms can be used
*/
bool st_lex::can_not_use_merged()
{
switch (sql_command)
{
case SQLCOM_CREATE_VIEW:
case SQLCOM_SHOW_CREATE:
return TRUE;
default:
return FALSE;
}
}
/*
Detect that we need only table structure of derived table/view

1
sql/sql_lex.h
View File

@@ -749,6 +749,7 @@ typedef struct st_lex
bool can_be_merged();
bool can_use_merged();
bool can_not_use_merged();
bool only_view_structure();
} LEX;

5
sql/sql_view.cc
View File

@@ -659,7 +659,8 @@ mysql_make_view(File_parser *parser, TABLE_LIST *table)
if (table->algorithm != VIEW_ALGORITHM_TMEPTABLE &&
lex->can_be_merged() &&
(table->select_lex->master_unit() != &old_lex->unit ||
old_lex->can_use_merged()))
old_lex->can_use_merged()) &&
!old_lex->can_not_use_merged())
{
/*
TODO: support multi tables substitutions
@@ -672,6 +673,7 @@ mysql_make_view(File_parser *parser, TABLE_LIST *table)
DBUG_ASSERT(view_table != 0);
table->effective_algorithm= VIEW_ALGORITHM_MERGE;
DBUG_PRINT("info", ("algorithm: MERGE"));
table->updatable= (table->updatable_view != 0);
if (old_next)
@@ -701,6 +703,7 @@ mysql_make_view(File_parser *parser, TABLE_LIST *table)
}
table->effective_algorithm= VIEW_ALGORITHM_TMEPTABLE;
DBUG_PRINT("info", ("algorithm: TEMPORARY TABLE"));
lex->select_lex.linkage= DERIVED_TABLE_TYPE;
table->updatable= 0;