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-rw-r--r--mysql-test/r/flush.result50
-rw-r--r--mysql-test/t/flush.test31
-rw-r--r--sql/sql_base.cc6
-rw-r--r--sql/sql_base.h5
-rw-r--r--sql/sql_reload.cc42
-rw-r--r--sql/sql_yacc.yy4
6 files changed, 117 insertions, 21 deletions
diff --git a/mysql-test/r/flush.result b/mysql-test/r/flush.result
index aee18d91edf..ced8306c3ab 100644
--- a/mysql-test/r/flush.result
+++ b/mysql-test/r/flush.result
@@ -373,3 +373,53 @@ commit;
# --> connection con2
# --> connection default
drop table t1;
+#
+# Test for bug #55273 "FLUSH TABLE tm WITH READ LOCK for Merge table
+# causes assert failure".
+#
+drop table if exists t1, t2, tm;
+create table t1 (i int);
+create table t2 (i int);
+create table tm (i int) engine=merge union=(t1, t2);
+insert into t1 values (1), (2);
+insert into t2 values (3), (4);
+# The below statement should succeed and lock merge
+# table for read. Only merge table gets flushed and
+# not underlying tables.
+flush tables tm with read lock;
+select * from tm;
+i
+1
+2
+3
+4
+# Check that underlying tables are locked.
+select * from t1;
+i
+1
+2
+select * from t2;
+i
+3
+4
+unlock tables;
+# This statement should succeed as well and flush
+# all tables in the list.
+flush tables tm, t1, t2 with read lock;
+select * from tm;
+i
+1
+2
+3
+4
+# Naturally, underlying tables should be locked in this case too.
+select * from t1;
+i
+1
+2
+select * from t2;
+i
+3
+4
+unlock tables;
+drop tables tm, t1, t2;
diff --git a/mysql-test/t/flush.test b/mysql-test/t/flush.test
index d4c3533847d..1cafbe3e6bd 100644
--- a/mysql-test/t/flush.test
+++ b/mysql-test/t/flush.test
@@ -546,3 +546,34 @@ disconnect con2;
connection default;
drop table t1;
+
+--echo #
+--echo # Test for bug #55273 "FLUSH TABLE tm WITH READ LOCK for Merge table
+--echo # causes assert failure".
+--echo #
+--disable_warnings
+drop table if exists t1, t2, tm;
+--enable_warnings
+create table t1 (i int);
+create table t2 (i int);
+create table tm (i int) engine=merge union=(t1, t2);
+insert into t1 values (1), (2);
+insert into t2 values (3), (4);
+--echo # The below statement should succeed and lock merge
+--echo # table for read. Only merge table gets flushed and
+--echo # not underlying tables.
+flush tables tm with read lock;
+select * from tm;
+--echo # Check that underlying tables are locked.
+select * from t1;
+select * from t2;
+unlock tables;
+--echo # This statement should succeed as well and flush
+--echo # all tables in the list.
+flush tables tm, t1, t2 with read lock;
+select * from tm;
+--echo # Naturally, underlying tables should be locked in this case too.
+select * from t1;
+select * from t2;
+unlock tables;
+drop tables tm, t1, t2;
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index 8cd0ce4432a..e2eb836a958 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -4522,13 +4522,15 @@ lock_table_names(THD *thd,
! (flags & MYSQL_OPEN_SKIP_TEMPORARY) &&
find_temporary_table(thd, table))))
{
- if (schema_set.insert(table))
+ if (! (flags & MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK) &&
+ schema_set.insert(table))
return TRUE;
mdl_requests.push_front(&table->mdl_request);
}
}
- if (! mdl_requests.is_empty())
+ if (! (flags & MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK) &&
+ ! mdl_requests.is_empty())
{
/*
Scoped locks: Take intention exclusive locks on all involved
diff --git a/sql/sql_base.h b/sql/sql_base.h
index a21850355b4..b1a730ad277 100644
--- a/sql/sql_base.h
+++ b/sql/sql_base.h
@@ -122,6 +122,11 @@ TABLE *open_ltable(THD *thd, TABLE_LIST *table_list, thr_lock_type update,
(LONG_TIMEOUT = 1 year) rather than the user-supplied timeout value.
*/
#define MYSQL_LOCK_IGNORE_TIMEOUT 0x0800
+/**
+ When acquiring "strong" (SNW, SNRW, X) metadata locks on tables to
+ be open do not acquire global and schema-scope IX locks.
+*/
+#define MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK 0x1000
/** Please refer to the internals manual. */
#define MYSQL_OPEN_REOPEN (MYSQL_OPEN_IGNORE_FLUSH |\
diff --git a/sql/sql_reload.cc b/sql/sql_reload.cc
index bf38af78536..35f27408247 100644
--- a/sql/sql_reload.cc
+++ b/sql/sql_reload.cc
@@ -328,7 +328,6 @@ bool reload_acl_and_cache(THD *thd, unsigned long options,
-------------------------------------
- you can't flush WITH READ LOCK a non-existent table
- you can't flush WITH READ LOCK under LOCK TABLES
- - currently incompatible with the GRL (@todo: fix)
Effect on views and temporary tables.
------------------------------------
@@ -338,6 +337,13 @@ bool reload_acl_and_cache(THD *thd, unsigned long options,
if there is a base table, it's used, otherwise ER_NO_SUCH_TABLE
is returned.
+ Handling of MERGE tables
+ ------------------------
+ For MERGE table this statement will open and lock child tables
+ for read (it is impossible to lock parent table without it).
+ Child tables won't be flushed unless they are explicitly present
+ in the statement's table list.
+
Implicit commit
---------------
This statement causes an implicit commit before and
@@ -354,7 +360,6 @@ bool flush_tables_with_read_lock(THD *thd, TABLE_LIST *all_tables)
{
Lock_tables_prelocking_strategy lock_tables_prelocking_strategy;
TABLE_LIST *table_list;
- MDL_request_list mdl_requests;
/*
This is called from SQLCOM_FLUSH, the transaction has
@@ -368,17 +373,13 @@ bool flush_tables_with_read_lock(THD *thd, TABLE_LIST *all_tables)
}
/*
- Acquire SNW locks on tables to be flushed. We can't use
- lock_table_names() here as this call will also acquire global IX
- and database-scope IX locks on the tables, and this will make
+ Acquire SNW locks on tables to be flushed. Don't acquire global
+ IX and database-scope IX locks on the tables as this will make
this statement incompatible with FLUSH TABLES WITH READ LOCK.
*/
- for (table_list= all_tables; table_list;
- table_list= table_list->next_global)
- mdl_requests.push_front(&table_list->mdl_request);
-
- if (thd->mdl_context.acquire_locks(&mdl_requests,
- thd->variables.lock_wait_timeout))
+ if (lock_table_names(thd, all_tables, NULL,
+ thd->variables.lock_wait_timeout,
+ MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK))
goto error;
DEBUG_SYNC(thd,"flush_tables_with_read_lock_after_acquire_locks");
@@ -390,21 +391,24 @@ bool flush_tables_with_read_lock(THD *thd, TABLE_LIST *all_tables)
tdc_remove_table(thd, TDC_RT_REMOVE_UNUSED,
table_list->db,
table_list->table_name, FALSE);
-
- /* Skip views and temporary tables. */
- table_list->required_type= FRMTYPE_TABLE; /* Don't try to flush views. */
- table_list->open_type= OT_BASE_ONLY; /* Ignore temporary tables. */
+ /* Reset ticket to satisfy asserts in open_tables(). */
+ table_list->mdl_request.ticket= NULL;
}
/*
Before opening and locking tables the below call also waits
for old shares to go away, so the fact that we don't pass
MYSQL_LOCK_IGNORE_FLUSH flag to it is important.
+ Also we don't pass MYSQL_OPEN_HAS_MDL_LOCK flag as we want
+ to open underlying tables if merge table is flushed.
+ For underlying tables of the merge the below call has to
+ acquire SNW locks to ensure that they can be locked for
+ read without further waiting.
*/
- if (open_and_lock_tables(thd, all_tables, FALSE,
- MYSQL_OPEN_HAS_MDL_LOCK,
- &lock_tables_prelocking_strategy) ||
- thd->locked_tables_list.init_locked_tables(thd))
+ if (open_and_lock_tables(thd, all_tables, FALSE,
+ MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK,
+ &lock_tables_prelocking_strategy) ||
+ thd->locked_tables_list.init_locked_tables(thd))
{
goto error;
}
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 83e9078f5cb..2ee2d83f9d2 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -11278,7 +11278,11 @@ opt_with_read_lock:
TABLE_LIST *tables= Lex->query_tables;
Lex->type|= REFRESH_READ_LOCK;
for (; tables; tables= tables->next_global)
+ {
tables->mdl_request.set_type(MDL_SHARED_NO_WRITE);
+ tables->required_type= FRMTYPE_TABLE; /* Don't try to flush views. */
+ tables->open_type= OT_BASE_ONLY; /* Ignore temporary tables. */
+ }
}
;
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