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Implementation of Monty's idea: Now we can open mysql.proc table for lookup

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of stored routines definitions even if we already have some tables open and
locked. To avoid deadlocks in this case we have to put certain restrictions
on locking of mysql.proc table.

This allows to use stored routines safely under LOCK TABLES without explicitly
mentioning mysql.proc in the list of locked tables. It also fixes bug #11554
"Server crashes on statement indirectly using non-cached function".
This commit is contained in:
dlenev@mysql.com
2005-07-13 13:48:13 +04:00
parent f5f434cf9f
commit f334ea1fc6
16 changed files with 459 additions and 202 deletions
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15
mysql-test/r/sp-error.result
View File

@ -286,6 +286,19 @@ ERROR 42000: OUT or INOUT argument 2 for routine test.p is not a variable
call p(42, @tmp_y, 43)|
ERROR 42000: OUT or INOUT argument 3 for routine test.p is not a variable
drop procedure p|
create procedure p() begin end|
lock table t1 read|
call p()|
unlock tables|
drop procedure p|
lock tables t1 read, mysql.proc write|
ERROR HY000: You can't combine write-locking of system 'mysql.proc' table with other tables
lock tables mysql.proc write, mysql.user write|
ERROR HY000: You can't combine write-locking of system 'mysql.proc' table with other tables
lock tables t1 read, mysql.proc read|
unlock tables|
lock tables mysql.proc write|
unlock tables|
create procedure bug1965()
begin
declare c cursor for select val from t1 order by valname;
@ -477,7 +490,7 @@ begin
select * from t1;
end|
lock table t1 read|
call bug9566()|
alter procedure bug9566 comment 'Some comment'|
ERROR HY000: Table 'proc' was not locked with LOCK TABLES
unlock tables|
drop procedure bug9566|

9
mysql-test/r/sp-threads.result
View File

@ -55,3 +55,12 @@ call bug11158();
unlock tables;
drop procedure bug11158;
drop table t1, t2;
drop function if exists bug11554;
drop view if exists v1;
create table t1 (i int);
create function bug11554 () returns int return 1;
create view v1 as select bug11554() as f;
insert into t1 (select f from v1);
drop function bug11554;
drop table t1;
drop view v1;

33
mysql-test/t/sp-error.test
View File

@ -386,6 +386,29 @@ call p(42, @tmp_y, 43)|
drop procedure p|
#
# Let us test that we can access mysql.proc table for routines
# definitions lookup without locking it explicitly.
#
create procedure p() begin end|
lock table t1 read|
# This should succeed
call p()|
unlock tables|
drop procedure p|
# Let us check restrictions which this ability puts on mysql.proc locking.
--error ER_WRONG_LOCK_OF_SYSTEM_TABLE
lock tables t1 read, mysql.proc write|
--error ER_WRONG_LOCK_OF_SYSTEM_TABLE
lock tables mysql.proc write, mysql.user write|
# Locking for read should be OK
lock tables t1 read, mysql.proc read|
unlock tables|
# You also should be able lock only mysql.proc for write
lock tables mysql.proc write|
unlock tables|
#
# BUG#1965
#
@ -676,9 +699,7 @@ create procedure bug6600()
# BUG#9566: explicit LOCK TABLE and store procedures result in illegal state
#
# We should not think that mysql.proc table does not exist if we are unable
# to open it under LOCK TABLE or in prelocked mode. Probably this test
# should be removed when Monty will allow access to mysql.proc without
# locking it.
# to open it under LOCK TABLE or in prelocked mode.
#
--disable_warnings
drop procedure if exists bug9566|
@ -688,9 +709,11 @@ begin
select * from t1;
end|
lock table t1 read|
# This should fail because we forgot to lock mysql.proc table explicitly
# This should fail since we forgot to lock mysql.proc for writing
# explicitly, and we can't open mysql.proc for _writing_ if there
# are locked tables.
--error 1100
call bug9566()|
alter procedure bug9566 comment 'Some comment'|
unlock tables|
# This should succeed
drop procedure bug9566|

19
mysql-test/t/sp-threads.test
View File

@ -111,6 +111,25 @@ connection con1root;
drop procedure bug11158;
drop table t1, t2;
#
# BUG#11554: Server crashes on statement indirectly using non-cached function
#
--disable_warnings
drop function if exists bug11554;
drop view if exists v1;
--enable_warnings
create table t1 (i int);
create function bug11554 () returns int return 1;
create view v1 as select bug11554() as f;
connection con2root;
# This should not crash server
insert into t1 (select f from v1);
# Clean-up
connection con1root;
drop function bug11554;
drop table t1;
drop view v1;
#
# BUG#NNNN: New bug synopsis
#

13
sql/lock.cc
View File

@ -425,6 +425,19 @@ static MYSQL_LOCK *get_lock_data(THD *thd, TABLE **table_ptr, uint count,
tables+=table_ptr[i]->file->lock_count();
lock_count++;
}
/*
To be able to open and lock for reading system tables like 'mysql.proc',
when we already have some tables opened and locked, and avoid deadlocks
we have to disallow write-locking of these tables with any other tables.
*/
if (table_ptr[i]->s->system_table &&
table_ptr[i]->reginfo.lock_type >= TL_WRITE_ALLOW_WRITE &&
count != 1)
{
my_error(ER_WRONG_LOCK_OF_SYSTEM_TABLE, MYF(0), table_ptr[i]->s->db,
table_ptr[i]->s->table_name);
return 0;
}
}
if (!(sql_lock= (MYSQL_LOCK*)

2
sql/mysql_priv.h
View File

@ -735,7 +735,7 @@ bool mysql_truncate(THD *thd, TABLE_LIST *table_list, bool dont_send_ok);
bool mysql_create_or_drop_trigger(THD *thd, TABLE_LIST *tables, bool create);
TABLE *open_ltable(THD *thd, TABLE_LIST *table_list, thr_lock_type update);
TABLE *open_table(THD *thd, TABLE_LIST *table_list, MEM_ROOT* mem,
bool *refresh);
bool *refresh, uint flags);
TABLE *reopen_name_locked_table(THD* thd, TABLE_LIST* table);
TABLE *find_locked_table(THD *thd, const char *db,const char *table_name);
bool reopen_table(TABLE *table,bool locked);

2
sql/share/errmsg.txt
View File

@ -5362,3 +5362,5 @@ ER_NO_DEFAULT_FOR_VIEW_FIELD
eng "Field of view '%-.64s.%-.64s' underlying table doesn't have a default value"
ER_SP_NO_RECURSION
eng "Recursive stored routines are not allowed."
ER_WRONG_LOCK_OF_SYSTEM_TABLE
eng "You can't combine write-locking of system '%-.64s.%-.64s' table with other tables"

296
sql/sp.cc
View File

@ -61,57 +61,152 @@ bool mysql_proc_table_exists= 1;
/* Tells what SP_DEFAULT_ACCESS should be mapped to */
#define SP_DEFAULT_ACCESS_MAPPING SP_CONTAINS_SQL
/* *opened=true means we opened ourselves */
static int
db_find_routine_aux(THD *thd, int type, sp_name *name,
enum thr_lock_type ltype, TABLE **tablep, bool *opened)
{
TABLE *table;
byte key[NAME_LEN*2+4+1]; // db, name, optional key length type
DBUG_ENTER("db_find_routine_aux");
DBUG_PRINT("enter", ("type: %d name: %*s",
type, name->m_name.length, name->m_name.str));
*opened= FALSE;
*tablep= 0;
/*
Close mysql.proc, opened with open_proc_table_for_read().
SYNOPSIS
close_proc_table()
thd Thread context
*/
static void close_proc_table(THD *thd)
{
close_thread_tables(thd);
thd->pop_open_tables_state();
}
/*
Open the mysql.proc table for read.
SYNOPSIS
open_proc_table_for_read()
thd Thread context
NOTES
Thanks to restrictions which we put on opening and locking of
this table for writing, we can open and lock it for reading
even when we already have some other tables open and locked.
One must call close_proc_table() to close table opened with
this call.
RETURN
0 Error
# Pointer to TABLE object of mysql.proc
*/
static TABLE *open_proc_table_for_read(THD *thd)
{
TABLE_LIST tables;
TABLE *table;
bool old_open_tables= thd->open_tables != 0;
bool refresh;
DBUG_ENTER("open_proc_table");
/*
Speed up things if mysql.proc doesn't exists. mysql_proc_table_exists
is set when we create or read stored procedure or on flush privileges.
*/
if (!mysql_proc_table_exists && ltype == TL_READ)
DBUG_RETURN(SP_OPEN_TABLE_FAILED);
if (!mysql_proc_table_exists)
DBUG_RETURN(0);
if (thd->lex->proc_table)
table= thd->lex->proc_table->table;
else
{
for (table= thd->open_tables ; table ; table= table->next)
if (strcmp(table->s->db, "mysql") == 0 &&
strcmp(table->s->table_name, "proc") == 0)
break;
}
if (!table)
{
TABLE_LIST tables;
if (thd->push_open_tables_state())
DBUG_RETURN(0);
memset(&tables, 0, sizeof(tables));
tables.db= (char*)"mysql";
tables.table_name= tables.alias= (char*)"proc";
if (! (table= open_ltable(thd, &tables, ltype)))
{
/*
Under explicit LOCK TABLES or in prelocked mode we should not
say that mysql.proc table does not exist if we are unable to
open it since this condition may be transient.
*/
if (!(thd->locked_tables || thd->prelocked_mode))
mysql_proc_table_exists= 0;
DBUG_RETURN(SP_OPEN_TABLE_FAILED);
}
*opened= TRUE;
bzero((char*) &tables, sizeof(tables));
tables.db= (char*) "mysql";
tables.table_name= tables.alias= (char*)"proc";
if (!(table= open_table(thd, &tables, thd->mem_root, &refresh,
MYSQL_LOCK_IGNORE_FLUSH)))
{
thd->pop_open_tables_state();
mysql_proc_table_exists= 0;
DBUG_RETURN(0);
}
mysql_proc_table_exists= 1;
DBUG_ASSERT(table->s->system_table);
table->reginfo.lock_type= TL_READ;
/*
If we have other tables opened, we have to ensure we are not blocked
by a flush tables or global read lock, as this could lead to a deadlock
*/
if (!(thd->lock= mysql_lock_tables(thd, &table, 1,
old_open_tables ?
(MYSQL_LOCK_IGNORE_GLOBAL_READ_LOCK |
MYSQL_LOCK_IGNORE_FLUSH) : 0)))
{
close_proc_table(thd);
DBUG_RETURN(0);
}
DBUG_RETURN(table);
}
/*
Open the mysql.proc table for update.
SYNOPSIS
open_proc_table_for_update()
thd Thread context
NOTES
Table opened with this call should closed using close_thread_tables().
RETURN
0 Error
# Pointer to TABLE object of mysql.proc
*/
static TABLE *open_proc_table_for_update(THD *thd)
{
TABLE_LIST tables;
TABLE *table;
DBUG_ENTER("open_proc_table");
bzero((char*) &tables, sizeof(tables));
tables.db= (char*) "mysql";
tables.table_name= tables.alias= (char*)"proc";
tables.lock_type= TL_WRITE;
table= open_ltable(thd, &tables, TL_WRITE);
/*
Under explicit LOCK TABLES or in prelocked mode we should not
say that mysql.proc table does not exist if we are unable to
open and lock it for writing since this condition may be
transient.
*/
if (!(thd->locked_tables || thd->prelocked_mode) || table)
mysql_proc_table_exists= test(table);
DBUG_RETURN(table);
}
/*
Find row in open mysql.proc table representing stored routine.
SYNOPSIS
db_find_routine_aux()
thd Thread context
type Type of routine to find (function or procedure)
name Name of routine
table TABLE object for open mysql.proc table.
RETURN VALUE
SP_OK - Routine found
SP_KEY_NOT_FOUND- No routine with given name
*/
static int
db_find_routine_aux(THD *thd, int type, sp_name *name, TABLE *table)
{
byte key[NAME_LEN*2+4+1]; // db, name, optional key length type
DBUG_ENTER("db_find_routine_aux");
DBUG_PRINT("enter", ("type: %d name: %*s",
type, name->m_name.length, name->m_name.str));
/*
Create key to find row. We have to use field->store() to be able to
@ -121,9 +216,7 @@ db_find_routine_aux(THD *thd, int type, sp_name *name,
same fields.
*/
if (name->m_name.length > table->field[1]->field_length)
{
DBUG_RETURN(SP_KEY_NOT_FOUND);
}
table->field[0]->store(name->m_db.str, name->m_db.length, &my_charset_bin);
table->field[1]->store(name->m_name.str, name->m_name.length,
&my_charset_bin);
@ -134,15 +227,33 @@ db_find_routine_aux(THD *thd, int type, sp_name *name,
if (table->file->index_read_idx(table->record[0], 0,
key, table->key_info->key_length,
HA_READ_KEY_EXACT))
{
DBUG_RETURN(SP_KEY_NOT_FOUND);
}
*tablep= table;
DBUG_RETURN(SP_OK);
}
/*
Find routine definition in mysql.proc table and create corresponding
sp_head object for it.
SYNOPSIS
db_find_routine()
thd Thread context
type Type of routine (TYPE_ENUM_PROCEDURE/...)
name Name of routine
sphp Out parameter in which pointer to created sp_head
object is returned (0 in case of error).
NOTE
This function may damage current LEX during execution, so it is good
idea to create temporary LEX and make it active before calling it.
RETURN VALUE
0 - Success
non-0 - Error (may be one of special codes like SP_KEY_NOT_FOUND)
*/
static int
db_find_routine(THD *thd, int type, sp_name *name, sp_head **sphp)
{
@ -150,7 +261,6 @@ db_find_routine(THD *thd, int type, sp_name *name, sp_head **sphp)
TABLE *table;
const char *params, *returns, *body;
int ret;
bool opened;
const char *definer;
longlong created;
longlong modified;
@ -164,8 +274,11 @@ db_find_routine(THD *thd, int type, sp_name *name, sp_head **sphp)
DBUG_PRINT("enter", ("type: %d name: %*s",
type, name->m_name.length, name->m_name.str));
ret= db_find_routine_aux(thd, type, name, TL_READ, &table, &opened);
if (ret != SP_OK)
*sphp= 0; // In case of errors
if (!(table= open_proc_table_for_read(thd)))
DBUG_RETURN(SP_OPEN_TABLE_FAILED);
if ((ret= db_find_routine_aux(thd, type, name, table)) != SP_OK)
goto done;
if (table->s->fields != MYSQL_PROC_FIELD_COUNT)
@ -257,11 +370,8 @@ db_find_routine(THD *thd, int type, sp_name *name, sp_head **sphp)
chistics.comment.str= ptr;
chistics.comment.length= length;
if (opened)
{
opened= FALSE;
close_thread_tables(thd, 0, 1);
}
close_proc_table(thd);
table= 0;
{
String defstr;
@ -337,9 +447,8 @@ db_find_routine(THD *thd, int type, sp_name *name, sp_head **sphp)
}
done:
if (opened)
close_thread_tables(thd);
if (table)
close_proc_table(thd);
DBUG_RETURN(ret);
}
@ -362,7 +471,6 @@ db_create_routine(THD *thd, int type, sp_head *sp)
{
int ret;
TABLE *table;
TABLE_LIST tables;
char definer[HOSTNAME_LENGTH+USERNAME_LENGTH+2];
char olddb[128];
bool dbchanged;
@ -377,11 +485,7 @@ db_create_routine(THD *thd, int type, sp_head *sp)
goto done;
}
memset(&tables, 0, sizeof(tables));
tables.db= (char*)"mysql";
tables.table_name= tables.alias= (char*)"proc";
if (! (table= open_ltable(thd, &tables, TL_WRITE)))
if (!(table= open_proc_table_for_update(thd)))
ret= SP_OPEN_TABLE_FAILED;
else
{
@ -491,20 +595,18 @@ db_drop_routine(THD *thd, int type, sp_name *name)
{
TABLE *table;
int ret;
bool opened;
DBUG_ENTER("db_drop_routine");
DBUG_PRINT("enter", ("type: %d name: %*s",
type, name->m_name.length, name->m_name.str));
ret= db_find_routine_aux(thd, type, name, TL_WRITE, &table, &opened);
if (ret == SP_OK)
if (!(table= open_proc_table_for_update(thd)))
DBUG_RETURN(SP_OPEN_TABLE_FAILED);
if ((ret= db_find_routine_aux(thd, type, name, table)) == SP_OK)
{
if (table->file->delete_row(table->record[0]))
ret= SP_DELETE_ROW_FAILED;
}
if (opened)
close_thread_tables(thd);
close_thread_tables(thd);
DBUG_RETURN(ret);
}
@ -519,8 +621,9 @@ db_update_routine(THD *thd, int type, sp_name *name, st_sp_chistics *chistics)
DBUG_PRINT("enter", ("type: %d name: %*s",
type, name->m_name.length, name->m_name.str));
ret= db_find_routine_aux(thd, type, name, TL_WRITE, &table, &opened);
if (ret == SP_OK)
if (!(table= open_proc_table_for_update(thd)))
DBUG_RETURN(SP_OPEN_TABLE_FAILED);
if ((ret= db_find_routine_aux(thd, type, name, table)) == SP_OK)
{
store_record(table,record[1]);
table->timestamp_field_type= TIMESTAMP_NO_AUTO_SET;
@ -538,8 +641,7 @@ db_update_routine(THD *thd, int type, sp_name *name, st_sp_chistics *chistics)
if ((table->file->update_row(table->record[1],table->record[0])))
ret= SP_WRITE_ROW_FAILED;
}
if (opened)
close_thread_tables(thd);
close_thread_tables(thd);
DBUG_RETURN(ret);
}
@ -741,20 +843,9 @@ sp_drop_db_routines(THD *thd, char *db)
memset(key+keylen, (int)' ', 64-keylen); // Pad with space
keylen= sizeof(key);
for (table= thd->open_tables ; table ; table= table->next)
if (strcmp(table->s->db, "mysql") == 0 &&
strcmp(table->s->table_name, "proc") == 0)
break;
if (! table)
{
TABLE_LIST tables;
memset(&tables, 0, sizeof(tables));
tables.db= (char*)"mysql";
tables.table_name= tables.alias= (char*)"proc";
if (! (table= open_ltable(thd, &tables, TL_WRITE)))
DBUG_RETURN(SP_OPEN_TABLE_FAILED);
}
ret= SP_OPEN_TABLE_FAILED;
if (!(table= open_proc_table_for_update(thd)))
goto err;
ret= SP_OK;
table->file->ha_index_init(0);
@ -764,7 +855,8 @@ sp_drop_db_routines(THD *thd, char *db)
int nxtres;
bool deleted= FALSE;
do {
do
{
if (! table->file->delete_row(table->record[0]))
deleted= TRUE; /* We deleted something */
else
@ -784,6 +876,7 @@ sp_drop_db_routines(THD *thd, char *db)
close_thread_tables(thd);
err:
DBUG_RETURN(ret);
}
@ -977,9 +1070,7 @@ sp_find_function(THD *thd, sp_name *name, bool cache_only)
if (!(sp= sp_cache_lookup(&thd->sp_func_cache, name)) &&
!cache_only)
{
if (db_find_routine(thd, TYPE_ENUM_FUNCTION, name, &sp) != SP_OK)
sp= NULL;
else
if (db_find_routine(thd, TYPE_ENUM_FUNCTION, name, &sp) == SP_OK)
sp_cache_insert(&thd->sp_func_cache, sp);
}
DBUG_RETURN(sp);
@ -1057,26 +1148,6 @@ sp_show_status_function(THD *thd, const char *wild)
}
bool
sp_function_exists(THD *thd, sp_name *name)
{
TABLE *table;
bool ret= FALSE;
bool opened= FALSE;
DBUG_ENTER("sp_function_exists");
if (sp_cache_lookup(&thd->sp_func_cache, name) ||
db_find_routine_aux(thd, TYPE_ENUM_FUNCTION,
name, TL_READ,
&table, &opened) == SP_OK)
ret= TRUE;
if (opened)
close_thread_tables(thd, 0, 1);
thd->clear_error();
DBUG_RETURN(ret);
}
byte *
sp_lex_sp_key(const byte *ptr, uint *plen, my_bool first)
{
@ -1185,7 +1256,6 @@ sp_cache_routines(THD *thd, LEX *lex)
thd->lex= newlex;
/* Pass hint pointer to mysql.proc table */
newlex->proc_table= oldlex->proc_table;
newlex->current_select= NULL;
name.m_name.str= strchr(name.m_qname.str, '.');
name.m_db.length= name.m_name.str - name.m_qname.str;

3
sql/sp.h
View File

@ -74,9 +74,6 @@ sp_show_create_function(THD *thd, sp_name *name);
int
sp_show_status_function(THD *thd, const char *wild);
bool
sp_function_exists(THD *thd, sp_name *name);
/*
* For precaching of functions and procedures

61
sql/sql_base.cc
View File

@ -542,10 +542,9 @@ void close_thread_tables(THD *thd, bool lock_in_use, bool skip_derived,
bool close_thread_table(THD *thd, TABLE **table_ptr)
{
DBUG_ENTER("close_thread_table");
bool found_old_table= 0;
TABLE *table= *table_ptr;
DBUG_ENTER("close_thread_table");
DBUG_ASSERT(table->key_read == 0);
DBUG_ASSERT(table->file->inited == handler::NONE);
@ -972,18 +971,34 @@ TABLE *reopen_name_locked_table(THD* thd, TABLE_LIST* table_list)
}
/******************************************************************************
** open a table
** Uses a cache of open tables to find a table not in use.
** If refresh is a NULL pointer, then the is no version number checking and
** the table is not put in the thread-open-list
** If the return value is NULL and refresh is set then one must close
** all tables and retry the open
******************************************************************************/
/*
Open a table.
SYNOPSIS
open_table()
thd Thread context
table_list Open first table in list
refresh Pointer to memory that will be set to 1 if
we need to close all tables and reopen them
If this is a NULL pointer, then the is no version
number checking and the table is not put in the
thread-open-list
flags Bitmap of flags to modify how open works:
MYSQL_LOCK_IGNORE_FLUSH - Open table even if someone
has done a flush or namelock on it.
IMPLEMENTATION
Uses a cache of open tables to find a table not in use.
RETURN
NULL Open failed. If refresh is set then one should close
all other tables and retry the open
# Success. Pointer to TABLE object for open table.
*/
TABLE *open_table(THD *thd, TABLE_LIST *table_list, MEM_ROOT *mem_root,
bool *refresh)
bool *refresh, uint flags)
{
reg1 TABLE *table;
char key[MAX_DBKEY_LENGTH];
@ -1096,9 +1111,16 @@ TABLE *open_table(THD *thd, TABLE_LIST *table_list, MEM_ROOT *mem_root,
{
if (table->s->version != refresh_version)
{
if (flags & MYSQL_LOCK_IGNORE_FLUSH)
{
/* Force close at once after usage */
thd->version= table->s->version;
continue;
}
/*
** There is a refresh in progress for this table
** Wait until the table is freed or the thread is killed.
There is a refresh in progress for this table
Wait until the table is freed or the thread is killed.
*/
close_old_data_files(thd,thd->open_tables,0,0);
if (table->in_use != thd)
@ -1681,6 +1703,15 @@ static int open_unireg_entry(THD *thd, TABLE *entry, const char *db,
if (error == 5)
DBUG_RETURN(0); // we have just opened VIEW
/*
We can't mark all tables in 'mysql' database as system since we don't
allow to lock such tables for writing with any other tables (even with
other system tables) and some privilege tables need this.
*/
if (!my_strcasecmp(system_charset_info, db, "mysql") &&
!my_strcasecmp(system_charset_info, name, "proc"))
entry->s->system_table= 1;
if (Table_triggers_list::check_n_load(thd, db, name, entry))
goto err;
@ -1835,7 +1866,7 @@ int open_tables(THD *thd, TABLE_LIST **start, uint *counter)
}
(*counter)++;
if (!tables->table &&
!(tables->table= open_table(thd, tables, &new_frm_mem, &refresh)))
!(tables->table= open_table(thd, tables, &new_frm_mem, &refresh, 0)))
{
free_root(&new_frm_mem, MYF(MY_KEEP_PREALLOC));
if (tables->view)
@ -2010,7 +2041,7 @@ TABLE *open_ltable(THD *thd, TABLE_LIST *table_list, thr_lock_type lock_type)
thd->current_tablenr= 0;
/* open_ltable can be used only for BASIC TABLEs */
table_list->required_type= FRMTYPE_TABLE;
while (!(table= open_table(thd, table_list, thd->mem_root, &refresh)) &&
while (!(table= open_table(thd, table_list, thd->mem_root, &refresh, 0)) &&
refresh)
;

50
sql/sql_class.cc
View File

@ -156,6 +156,14 @@ bool foreign_key_prefix(Key *a, Key *b)
/****************************************************************************
** Thread specific functions
****************************************************************************/
Open_tables_state::Open_tables_state()
:version(refresh_version)
{
reset_open_tables_state();
}
/*
Pass nominal parameters to Statement constructor only to ensure that
the destructor works OK in case of error. The main_mem_root will be
@ -164,6 +172,7 @@ bool foreign_key_prefix(Key *a, Key *b)
THD::THD()
:Statement(CONVENTIONAL_EXECUTION, 0, ALLOC_ROOT_MIN_BLOCK_SIZE, 0),
Open_tables_state(),
user_time(0), global_read_lock(0), is_fatal_error(0),
rand_used(0), time_zone_used(0),
last_insert_id_used(0), insert_id_used(0), clear_next_insert_id(0),
@ -181,10 +190,8 @@ THD::THD()
db_length= col_access=0;
query_error= tmp_table_used= 0;
next_insert_id=last_insert_id=0;
open_tables= temporary_tables= handler_tables= derived_tables= 0;
hash_clear(&handler_tables_hash);
tmp_table=0;
lock=locked_tables=0;
used_tables=0;
cuted_fields= sent_row_count= 0L;
limit_found_rows= 0;
@ -230,7 +237,6 @@ THD::THD()
#ifndef NO_EMBEDDED_ACCESS_CHECKS
db_access=NO_ACCESS;
#endif
version=refresh_version; // For boot
*scramble= '\0';
init();
@ -259,7 +265,6 @@ THD::THD()
tablespace_op=FALSE;
ulong tmp=sql_rnd_with_mutex();
randominit(&rand, tmp + (ulong) &rand, tmp + (ulong) ::query_id);
prelocked_mode= NON_PRELOCKED;
}
@ -1775,3 +1780,40 @@ void THD::set_status_var_init()
{
bzero((char*) &status_var, sizeof(status_var));
}
/****************************************************************************
Handling of open and locked tables states.
This is used when we want to open/lock (and then close) some tables when
we already have a set of tables open and locked. We use these methods for
access to mysql.proc table to find definitions of stored routines.
****************************************************************************/
bool THD::push_open_tables_state()
{
Open_tables_state *state;
DBUG_ENTER("push_open_table_state");
/* Currently we only push things one level */
DBUG_ASSERT(open_state_list.elements == 0);
if (!(state= (Open_tables_state*) alloc(sizeof(*state))))
DBUG_RETURN(1); // Fatal error is set
/* Store state for currently open tables */
state->set_open_tables_state(this);
if (open_state_list.push_back(state, mem_root))
DBUG_RETURN(1); // Fatal error is set
reset_open_tables_state();
DBUG_RETURN(0);
}
void THD::pop_open_tables_state()
{
Open_tables_state *state;
DBUG_ENTER("pop_open_table_state");
/* Currently we only push things one level */
DBUG_ASSERT(open_state_list.elements == 1);
state= open_state_list.pop();
set_open_tables_state(state);
DBUG_VOID_RETURN;
}

144
sql/sql_class.h
View File

@ -932,13 +932,94 @@ enum prelocked_mode_type {NON_PRELOCKED= 0, PRELOCKED= 1,
PRELOCKED_UNDER_LOCK_TABLES= 2};
/*
Class that holds information about tables which were open and locked
by the thread. It is also used to save/restore this information in
push_open_tables_state()/pop_open_tables_state().
*/
class Open_tables_state
{
public:
/*
open_tables - list of regular tables in use by this thread
temporary_tables - list of temp tables in use by this thread
handler_tables - list of tables that were opened with HANDLER OPEN
and are still in use by this thread
*/
TABLE *open_tables, *temporary_tables, *handler_tables, *derived_tables;
/*
During a MySQL session, one can lock tables in two modes: automatic
or manual. In automatic mode all necessary tables are locked just before
statement execution, and all acquired locks are stored in 'lock'
member. Unlocking takes place automatically as well, when the
statement ends.
Manual mode comes into play when a user issues a 'LOCK TABLES'
statement. In this mode the user can only use the locked tables.
Trying to use any other tables will give an error. The locked tables are
stored in 'locked_tables' member. Manual locking is described in
the 'LOCK_TABLES' chapter of the MySQL manual.
See also lock_tables() for details.
*/
MYSQL_LOCK *lock;
/*
Tables that were locked with explicit or implicit LOCK TABLES.
(Implicit LOCK TABLES happens when we are prelocking tables for
execution of statement which uses stored routines. See description
THD::prelocked_mode for more info.)
*/
MYSQL_LOCK *locked_tables;
/*
prelocked_mode_type enum and prelocked_mode member are used for
indicating whenever "prelocked mode" is on, and what type of
"prelocked mode" is it.
Prelocked mode is used for execution of queries which explicitly
or implicitly (via views or triggers) use functions, thus may need
some additional tables (mentioned in query table list) for their
execution.
First open_tables() call for such query will analyse all functions
used by it and add all additional tables to table its list. It will
also mark this query as requiring prelocking. After that lock_tables()
will issue implicit LOCK TABLES for the whole table list and change
thd::prelocked_mode to non-0. All queries called in functions invoked
by the main query will use prelocked tables. Non-0 prelocked_mode
will also surpress mentioned analysys in those queries thus saving
cycles. Prelocked mode will be turned off once close_thread_tables()
for the main query will be called.
Note: Since not all "tables" present in table list are really locked
thd::prelocked_mode does not imply thd::locked_tables.
*/
prelocked_mode_type prelocked_mode;
ulong version;
uint current_tablenr;
Open_tables_state();
void set_open_tables_state(Open_tables_state *state)
{
*this= *state;
}
void reset_open_tables_state()
{
open_tables= temporary_tables= handler_tables= derived_tables= 0;
lock= locked_tables= 0;
prelocked_mode= NON_PRELOCKED;
}
};
/*
For each client connection we create a separate thread with THD serving as
a thread/connection descriptor
*/
class THD :public ilink,
public Statement
public Statement,
public Open_tables_state
{
public:
#ifdef EMBEDDED_LIBRARY
@ -1006,34 +1087,6 @@ public:
ulong master_access; /* Global privileges from mysql.user */
ulong db_access; /* Privileges for current db */
/*
open_tables - list of regular tables in use by this thread
temporary_tables - list of temp tables in use by this thread
handler_tables - list of tables that were opened with HANDLER OPEN
and are still in use by this thread
*/
TABLE *open_tables,*temporary_tables, *handler_tables, *derived_tables;
/*
During a MySQL session, one can lock tables in two modes: automatic
or manual. In automatic mode all necessary tables are locked just before
statement execution, and all acquired locks are stored in 'lock'
member. Unlocking takes place automatically as well, when the
statement ends.
Manual mode comes into play when a user issues a 'LOCK TABLES'
statement. In this mode the user can only use the locked tables.
Trying to use any other tables will give an error. The locked tables are
stored in 'locked_tables' member. Manual locking is described in
the 'LOCK_TABLES' chapter of the MySQL manual.
See also lock_tables() for details.
*/
MYSQL_LOCK *lock; /* Current locks */
/*
Tables that were locked with explicit or implicit LOCK TABLES.
(Implicit LOCK TABLES happens when we are prelocking tables for
execution of statement which uses stored routines. See description
THD::prelocked_mode for more info.)
*/
MYSQL_LOCK *locked_tables;
HASH handler_tables_hash;
/*
One thread can hold up to one named user-level lock. This variable
@ -1150,6 +1203,7 @@ public:
List <MYSQL_ERROR> warn_list;
uint warn_count[(uint) MYSQL_ERROR::WARN_LEVEL_END];
uint total_warn_count;
List <Open_tables_state> open_state_list;
/*
Id of current query. Statement can be reused to execute several queries
query_id is global in context of the whole MySQL server.
@ -1159,7 +1213,7 @@ public:
update auto-updatable fields (like auto_increment and timestamp).
*/
query_id_t query_id, warn_id;
ulong version, options, thread_id, col_access;
ulong options, thread_id, col_access;
/* Statement id is thread-wide. This counter is used to generate ids */
ulong statement_id_counter;
@ -1167,7 +1221,7 @@ public:
ulong row_count; // Row counter, mainly for errors and warnings
long dbug_thread_id;
pthread_t real_id;
uint current_tablenr,tmp_table,global_read_lock;
uint tmp_table, global_read_lock;
uint server_status,open_options,system_thread;
uint32 db_length;
uint select_number; //number of select (used for EXPLAIN)
@ -1218,31 +1272,6 @@ public:
long long_value;
} sys_var_tmp;
/*
prelocked_mode_type enum and prelocked_mode member are used for
indicating whenever "prelocked mode" is on, and what type of
"prelocked mode" is it.
Prelocked mode is used for execution of queries which explicitly
or implicitly (via views or triggers) use functions, thus may need
some additional tables (mentioned in query table list) for their
execution.
First open_tables() call for such query will analyse all functions
used by it and add all additional tables to table its list. It will
also mark this query as requiring prelocking. After that lock_tables()
will issue implicit LOCK TABLES for the whole table list and change
thd::prelocked_mode to non-0. All queries called in functions invoked
by the main query will use prelocked tables. Non-0 prelocked_mode
will also surpress mentioned analysys in those queries thus saving
cycles. Prelocked mode will be turned off once close_thread_tables()
for the main query will be called.
Note: Since not all "tables" present in table list are really locked
thd::relocked_mode does not imply thd::locked_tables.
*/
prelocked_mode_type prelocked_mode;
THD();
~THD();
@ -1428,8 +1457,11 @@ public:
(variables.sql_mode & MODE_STRICT_ALL_TABLES)));
}
void set_status_var_init();
bool push_open_tables_state();
void pop_open_tables_state();
};
#define tmp_disable_binlog(A) \
{ulong tmp_disable_binlog__save_options= (A)->options; \
(A)->options&= ~OPTION_BIN_LOG

2
sql/sql_lex.cc
View File

@ -145,7 +145,7 @@ void lex_start(THD *thd, uchar *buf,uint length)
lex->found_semicolon= 0;
lex->safe_to_cache_query= 1;
lex->time_zone_tables_used= 0;
lex->leaf_tables_insert= lex->proc_table= lex->query_tables= 0;
lex->leaf_tables_insert= lex->query_tables= 0;
lex->query_tables_last= &lex->query_tables;
lex->variables_used= 0;
lex->select_lex.parent_lex= lex;

1
sql/sql_lex.h
View File

@ -719,7 +719,6 @@ typedef struct st_lex
function)
*/
TABLE_LIST **query_tables_last;
TABLE_LIST *proc_table; /* refer to mysql.proc if it was opened by VIEW */
/* store original leaf_tables for INSERT SELECT and PS/SP */
TABLE_LIST *leaf_tables_insert;

4
sql/sql_table.cc
View File

@ -1760,7 +1760,7 @@ TABLE *create_table_from_items(THD *thd, HA_CREATE_INFO *create_info,
create_info, *extra_fields, *keys, 0,
select_field_count))
{
if (!(table= open_table(thd, create_table, thd->mem_root, (bool*) 0)))
if (!(table= open_table(thd, create_table, thd->mem_root, (bool*)0, 0)))
quick_rm_table(create_info->db_type, create_table->db,
table_case_name(create_info, create_table->table_name));
}
@ -3571,7 +3571,7 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
bzero((void*) &tbl, sizeof(tbl));
tbl.db= new_db;
tbl.table_name= tbl.alias= tmp_name;
new_table= open_table(thd, &tbl, thd->mem_root, 0);
new_table= open_table(thd, &tbl, thd->mem_root, 0, 0);
}
else
{

7
sql/table.h
View File

@ -163,6 +163,13 @@ typedef struct st_table_share
my_bool crashed;
my_bool is_view;
my_bool name_lock, replace_with_name_lock;
/*
TRUE if this is a system table like 'mysql.proc', which we want to be
able to open and lock even when we already have some tables open and
locked. To avoid deadlocks we have to put certain restrictions on
locking of this table for writing. FALSE - otherwise.
*/
my_bool system_table;
} TABLE_SHARE;