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Manual merge of patch for Bug#11749345 (formerly known as bug#38813)

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from 5.1->5.5.
This commit is contained in:
Dmitry Shulga 2011-05-21 00:13:12 +07:00
commit 34d731ef78
1 changed files with 185 additions and 155 deletions
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338
sql/sql_show.cc
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@ -2407,12 +2407,11 @@ bool schema_table_store_record(THD *thd, TABLE *table)
} }
int make_table_list(THD *thd, SELECT_LEX *sel, static int make_table_list(THD *thd, SELECT_LEX *sel,
LEX_STRING *db_name, LEX_STRING *table_name) LEX_STRING *db_name, LEX_STRING *table_name)
{ {
Table_ident *table_ident; Table_ident *table_ident;
table_ident= new Table_ident(thd, *db_name, *table_name, 1); table_ident= new Table_ident(thd, *db_name, *table_name, 1);
sel->init_query();
if (!sel->add_table_to_list(thd, table_ident, 0, 0, TL_READ, MDL_SHARED_READ)) if (!sel->add_table_to_list(thd, table_ident, 0, 0, TL_READ, MDL_SHARED_READ))
return 1; return 1;
return 0; return 0;
@ -2982,91 +2981,190 @@ make_table_name_list(THD *thd, List<LEX_STRING> *table_names, LEX *lex,
/** /**
@brief Fill I_S table for SHOW COLUMNS|INDEX commands Fill I_S table with data obtained by performing full-blown table open.
@param[in] thd thread handler @param thd Thread handler.
@param[in] tables TABLE_LIST for I_S table @param is_show_fields_or_keys Indicates whether it is a legacy SHOW
@param[in] schema_table pointer to I_S structure COLUMNS or SHOW KEYS statement.
@param[in] can_deadlock Indicates that deadlocks are possible @param table TABLE object for I_S table to be filled.
due to metadata locks, so to avoid @param schema_table I_S table description structure.
them we should not wait in case if @param orig_db_name Database name.
conflicting lock is present. @param orig_table_name Table name.
@param[in] open_tables_state_backup pointer to Open_tables_backup object @param open_tables_state_backup Open_tables_state object which is used
which is used to save|restore original to save/restore original status of
status of variables related to variables related to open tables state.
open tables state @param can_deadlock Indicates that deadlocks are possible
due to metadata locks, so to avoid
them we should not wait in case if
conflicting lock is present.
@return Operation status @retval FALSE - Success.
@retval 0 success @retval TRUE - Failure.
@retval 1 error
*/ */
static bool
static int fill_schema_table_by_open(THD *thd, bool is_show_fields_or_keys,
fill_schema_show_cols_or_idxs(THD *thd, TABLE_LIST *tables, TABLE *table, ST_SCHEMA_TABLE *schema_table,
ST_SCHEMA_TABLE *schema_table, LEX_STRING *orig_db_name,
bool can_deadlock, LEX_STRING *orig_table_name,
Open_tables_backup *open_tables_state_backup) Open_tables_backup *open_tables_state_backup,
bool can_deadlock)
{ {
LEX *lex= thd->lex; Query_arena i_s_arena(thd->mem_root,
bool res; Query_arena::STMT_CONVENTIONAL_EXECUTION),
LEX_STRING tmp_lex_string, tmp_lex_string1, *db_name, *table_name; backup_arena, *old_arena;
enum_sql_command save_sql_command= lex->sql_command; LEX *old_lex= thd->lex, temp_lex, *lex;
TABLE_LIST *show_table_list= tables->schema_select_lex->table_list.first; LEX_STRING db_name, table_name;
TABLE *table= tables->table; TABLE_LIST *table_list;
int error= 1; bool result= true;
DBUG_ENTER("fill_schema_show");
lex->all_selects_list= tables->schema_select_lex; DBUG_ENTER("fill_schema_table_by_open");
/* /*
Restore thd->temporary_tables to be able to process When a view is opened its structures are allocated on a permanent
temporary tables(only for 'show index' & 'show columns'). statement arena and linked into the LEX tree for the current statement
This should be changed when processing of temporary tables for (this happens even in cases when view is handled through TEMPTABLE
I_S tables will be done. algorithm).
To prevent this process from unnecessary hogging of memory in the permanent
arena of our I_S query and to avoid damaging its LEX we use temporary
arena and LEX for table/view opening.
Use temporary arena instead of statement permanent arena. Also make
it active arena and save original one for successive restoring.
*/ */
thd->temporary_tables= open_tables_state_backup->temporary_tables; old_arena= thd->stmt_arena;
thd->stmt_arena= &i_s_arena;
thd->set_n_backup_active_arena(&i_s_arena, &backup_arena);
/* Prepare temporary LEX. */
thd->lex= lex= &temp_lex;
lex_start(thd);
/* Disable constant subquery evaluation as we won't be locking tables. */
lex->context_analysis_only= CONTEXT_ANALYSIS_ONLY_VIEW;
/*
Some of process_table() functions rely on wildcard being passed from
old LEX (or at least being initialized).
*/
lex->wild= old_lex->wild;
/*
Since make_table_list() might change database and table name passed
to it we create copies of orig_db_name and orig_table_name here.
These copies are used for make_table_list() while unaltered values
are passed to process_table() functions.
*/
if (!thd->make_lex_string(&db_name, orig_db_name->str,
orig_db_name->length, FALSE) ||
!thd->make_lex_string(&table_name, orig_table_name->str,
orig_table_name->length, FALSE))
goto end;
/*
Create table list element for table to be open. Link it with the
temporary LEX. The latter is required to correctly open views and
produce table describing their structure.
*/
if (make_table_list(thd, &lex->select_lex, &db_name, &table_name))
goto end;
table_list= lex->select_lex.table_list.first;
if (is_show_fields_or_keys)
{
/*
Restore thd->temporary_tables to be able to process
temporary tables (only for 'show index' & 'show columns').
This should be changed when processing of temporary tables for
I_S tables will be done.
*/
thd->temporary_tables= open_tables_state_backup->temporary_tables;
}
else
{
/*
Apply optimization flags for table opening which are relevant for
this I_S table. We can't do this for SHOW COLUMNS/KEYS because of
backward compatibility.
*/
table_list->i_s_requested_object= schema_table->i_s_requested_object;
}
/* /*
Let us set fake sql_command so views won't try to merge Let us set fake sql_command so views won't try to merge
themselves into main statement. If we don't do this, themselves into main statement. If we don't do this,
SELECT * from information_schema.xxxx will cause problems. SELECT * from information_schema.xxxx will cause problems.
SQLCOM_SHOW_FIELDS is used because it satisfies 'only_view_structure()' SQLCOM_SHOW_FIELDS is used because it satisfies
'only_view_structure()'.
*/ */
lex->sql_command= SQLCOM_SHOW_FIELDS; lex->sql_command= SQLCOM_SHOW_FIELDS;
res= open_normal_and_derived_tables(thd, show_table_list, result= open_normal_and_derived_tables(thd, table_list,
(MYSQL_OPEN_IGNORE_FLUSH | (MYSQL_OPEN_IGNORE_FLUSH |
MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL | MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL |
(can_deadlock ? (can_deadlock ?
MYSQL_OPEN_FAIL_ON_MDL_CONFLICT : 0))); MYSQL_OPEN_FAIL_ON_MDL_CONFLICT : 0)));
lex->sql_command= save_sql_command; /*
Restore old value of sql_command back as it is being looked at in
process_table() function.
*/
lex->sql_command= old_lex->sql_command;
DEBUG_SYNC(thd, "after_open_table_ignore_flush"); DEBUG_SYNC(thd, "after_open_table_ignore_flush");
/* /*
get_all_tables() returns 1 on failure and 0 on success thus XXX: show_table_list has a flag i_is_requested,
return only these and not the result code of ::process_table() and when it's set, open_normal_and_derived_tables()
can return an error without setting an error message
in THD, which is a hack. This is why we have to
check for res, then for thd->is_error() and only then
for thd->main_da.sql_errno().
We should use show_table_list->alias instead of Again we don't do this for SHOW COLUMNS/KEYS because
show_table_list->table_name because table_name of backward compatibility.
could be changed during opening of I_S tables. It's safe
to use alias because alias contains original table name
in this case(this part of code is used only for
'show columns' & 'show statistics' commands).
*/ */
table_name= thd->make_lex_string(&tmp_lex_string1, show_table_list->alias, if (!is_show_fields_or_keys && result && thd->is_error() &&
strlen(show_table_list->alias), FALSE); thd->stmt_da->sql_errno() == ER_NO_SUCH_TABLE)
if (!show_table_list->view) {
db_name= thd->make_lex_string(&tmp_lex_string, show_table_list->db, /*
show_table_list->db_length, FALSE); Hide error for a non-existing table.
else For example, this error can occur when we use a where condition
db_name= &show_table_list->view_db; with a db name and table, but the table does not exist.
*/
result= false;
thd->clear_error();
}
else
{
result= schema_table->process_table(thd, table_list,
table, result,
orig_db_name,
orig_table_name);
}
error= test(schema_table->process_table(thd, show_table_list, end:
table, res, db_name, lex->unit.cleanup();
table_name));
thd->temporary_tables= 0; /* Restore original LEX value, statement's arena and THD arena values. */
close_tables_for_reopen(thd, &show_table_list, lex_end(thd->lex);
open_tables_state_backup->mdl_system_tables_svp);
DBUG_RETURN(error); if (i_s_arena.free_list)
i_s_arena.free_items();
/*
For safety reset list of open temporary tables before closing
all tables open within this Open_tables_state.
*/
thd->temporary_tables= NULL;
close_thread_tables(thd);
thd->mdl_context.rollback_to_savepoint(open_tables_state_backup->mdl_system_tables_svp);
thd->lex= old_lex;
thd->stmt_arena= old_arena;
thd->restore_active_arena(&i_s_arena, &backup_arena);
DBUG_RETURN(result);
} }
@ -3477,10 +3575,8 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
{ {
LEX *lex= thd->lex; LEX *lex= thd->lex;
TABLE *table= tables->table; TABLE *table= tables->table;
SELECT_LEX *old_all_select_lex= lex->all_selects_list;
SELECT_LEX *lsel= tables->schema_select_lex; SELECT_LEX *lsel= tables->schema_select_lex;
ST_SCHEMA_TABLE *schema_table= tables->schema_table; ST_SCHEMA_TABLE *schema_table= tables->schema_table;
SELECT_LEX sel;
LOOKUP_FIELD_VALUES lookup_field_vals; LOOKUP_FIELD_VALUES lookup_field_vals;
LEX_STRING *db_name, *table_name; LEX_STRING *db_name, *table_name;
bool with_i_schema; bool with_i_schema;
@ -3488,11 +3584,8 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
List<LEX_STRING> db_names; List<LEX_STRING> db_names;
List_iterator_fast<LEX_STRING> it(db_names); List_iterator_fast<LEX_STRING> it(db_names);
COND *partial_cond= 0; COND *partial_cond= 0;
uint derived_tables= lex->derived_tables;
int error= 1; int error= 1;
Open_tables_backup open_tables_state_backup; Open_tables_backup open_tables_state_backup;
uint8 save_context_analysis_only= lex->context_analysis_only;
Query_tables_list query_tables_list_backup;
#ifndef NO_EMBEDDED_ACCESS_CHECKS #ifndef NO_EMBEDDED_ACCESS_CHECKS
Security_context *sctx= thd->security_ctx; Security_context *sctx= thd->security_ctx;
#endif #endif
@ -3511,15 +3604,6 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
*/ */
can_deadlock= thd->mdl_context.has_locks(); can_deadlock= thd->mdl_context.has_locks();
lex->context_analysis_only|= CONTEXT_ANALYSIS_ONLY_VIEW;
lex->reset_n_backup_query_tables_list(&query_tables_list_backup);
/*
Restore Query_tables_list::sql_command value, which was reset
above, as ST_SCHEMA_TABLE::process_table() functions often rely
that this value reflects which SHOW statement is executed.
*/
lex->sql_command= query_tables_list_backup.sql_command;
/* /*
We should not introduce deadlocks even if we already have some We should not introduce deadlocks even if we already have some
tables open and locked, since we won't lock tables which we will tables open and locked, since we won't lock tables which we will
@ -3539,9 +3623,19 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
*/ */
if (lsel && lsel->table_list.first) if (lsel && lsel->table_list.first)
{ {
error= fill_schema_show_cols_or_idxs(thd, tables, schema_table, LEX_STRING db_name, table_name;
can_deadlock,
&open_tables_state_backup); db_name.str= lsel->table_list.first->db;
db_name.length= lsel->table_list.first->db_length;
table_name.str= lsel->table_list.first->table_name;
table_name.length= lsel->table_list.first->table_name_length;
error= fill_schema_table_by_open(thd, TRUE,
table, schema_table,
&db_name, &table_name,
&open_tables_state_backup,
can_deadlock);
goto err; goto err;
} }
@ -3595,12 +3689,6 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
it.rewind(); /* To get access to new elements in basis list */ it.rewind(); /* To get access to new elements in basis list */
while ((db_name= it++)) while ((db_name= it++))
{ {
LEX_STRING orig_db_name;
/* db_name can be changed in make_table_list() func */
if (!thd->make_lex_string(&orig_db_name, db_name->str,
db_name->length, FALSE))
goto err;
#ifndef NO_EMBEDDED_ACCESS_CHECKS #ifndef NO_EMBEDDED_ACCESS_CHECKS
if (!(check_access(thd, SELECT_ACL, db_name->str, if (!(check_access(thd, SELECT_ACL, db_name->str,
&thd->col_access, NULL, 0, 1) || &thd->col_access, NULL, 0, 1) ||
@ -3678,66 +3766,11 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
continue; continue;
} }
int res; if (fill_schema_table_by_open(thd, FALSE,
LEX_STRING tmp_lex_string; table, schema_table,
/* db_name, table_name,
Set the parent lex of 'sel' because it is needed by &open_tables_state_backup,
sel.init_query() which is called inside make_table_list. can_deadlock))
*/
sel.parent_lex= lex;
if (make_table_list(thd, &sel, db_name, table_name))
goto err;
TABLE_LIST *show_table_list= sel.table_list.first;
lex->all_selects_list= &sel;
lex->derived_tables= 0;
lex->sql_command= SQLCOM_SHOW_FIELDS;
show_table_list->i_s_requested_object=
schema_table->i_s_requested_object;
DEBUG_SYNC(thd, "before_open_in_get_all_tables");
res= open_normal_and_derived_tables(thd, show_table_list,
(MYSQL_OPEN_IGNORE_FLUSH |
MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL |
(can_deadlock ? MYSQL_OPEN_FAIL_ON_MDL_CONFLICT : 0)));
lex->sql_command= query_tables_list_backup.sql_command;
/*
XXX: show_table_list has a flag i_is_requested,
and when it's set, open_normal_and_derived_tables()
can return an error without setting an error message
in THD, which is a hack. This is why we have to
check for res, then for thd->is_error() only then
for thd->stmt_da->sql_errno().
*/
if (res && thd->is_error() &&
thd->stmt_da->sql_errno() == ER_NO_SUCH_TABLE)
{
/*
Hide error for not existing table.
This error can occur for example when we use
where condition with db name and table name and this
table does not exist.
*/
res= 0;
thd->clear_error();
}
else
{
/*
We should use show_table_list->alias instead of
show_table_list->table_name because table_name
could be changed during opening of I_S tables. It's safe
to use alias because alias contains original table name
in this case.
*/
thd->make_lex_string(&tmp_lex_string, show_table_list->alias,
strlen(show_table_list->alias), FALSE);
res= schema_table->process_table(thd, show_table_list, table,
res, &orig_db_name,
&tmp_lex_string);
close_tables_for_reopen(thd, &show_table_list,
open_tables_state_backup.mdl_system_tables_svp);
}
DBUG_ASSERT(!lex->query_tables_own_last);
if (res)
goto err; goto err;
} }
} }
@ -3753,10 +3786,7 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
error= 0; error= 0;
err: err:
thd->restore_backup_open_tables_state(&open_tables_state_backup); thd->restore_backup_open_tables_state(&open_tables_state_backup);
lex->restore_backup_query_tables_list(&query_tables_list_backup);
lex->derived_tables= derived_tables;
lex->all_selects_list= old_all_select_lex;
lex->context_analysis_only= save_context_analysis_only;
DBUG_RETURN(error); DBUG_RETURN(error);
} }