Hi, Nirbhay!
Just a couple of questions/comments, see below.
And please pay attention to Kristian's email about locking and parallel
replication. I don't think I can confidently review it in a patch, so
you may want to spend more time testing or analyzing that code.
Ok to push, when you're ready! Thanks!
On May 26, Nirbhay Choubey wrote:
revision-id: 56a2835872c4ac7296ec0ae2ff618822855b0fc0 (mariadb-10.1.8-82-g56a2835)
parent(s): 28c289626f318631d707f85b057a90af99018b06
author: Nirbhay Choubey
committer: Nirbhay Choubey
timestamp: 2016-05-26 20:42:47 -0400
message:
MDEV-5535: Cannot reopen temporary table
mysqld maintains a list of TABLE objects for all temporary
tables in THD, where each table is represented by a TABLE
object. A query referencing a temporary table for more than
once, however, failed with ER_CANT_REOPEN_TABLE error.
"because a TABLE_SHARE was allocate together with the TABLE, so
temporary tables always had one TABLE per TABLE_SHARE"
This patch lift this restriction by preserving the TABLE_SHARE
object of each created temporary table, so that multiple instances
of TABLE objects can be created.
better "by separating TABLE and TABLE_SHARE objects and storing
TABLE_SHARE's in the list in a THD, and TABLE's in the list in
the corresponding TABLE_SHARE"
diff --git a/sql/rpl_rli.cc b/sql/rpl_rli.cc
index 7bdd9c1..77f458b 100644
--- a/sql/rpl_rli.cc
+++ b/sql/rpl_rli.cc
@@ -1060,24 +1061,43 @@ void Relay_log_info::inc_group_relay_log_pos(ulonglong log_pos,
void Relay_log_info::close_temporary_tables()
{
- TABLE *table,*next;
DBUG_ENTER("Relay_log_info::close_temporary_tables");
- for (table=save_temporary_tables ; table ; table=next)
+ TMP_TABLE_SHARE *share;
+ TABLE *table;
+
+ while ((share= save_temporary_tables.pop_front()))
{
- next=table->next;
+ /*
+ Iterate over the list of tables for this TABLE_SHARE and close them.
+ */
+ while ((table= share->all_tmp_tables.pop_front()))
+ {
+ DBUG_PRINT("tmptable", ("closing table: '%s'.'%s'",
+ table->s->db.str, table->s->table_name.str));
+
+ /* Reset in_use as the table may have been created by another thd */
+ table->in_use= 0;
+ free_io_cache(table);
+ /*
+ Lets not free TABLE_SHARE here as there could be multiple TABLEs opened
+ for the same table (TABLE_SHARE).
+ */
+ closefrm(table, false);
+ my_free(table);
+ }
- /* Reset in_use as the table may have been created by another thd */
- table->in_use=0;
/*
Don't ask for disk deletion. For now, anyway they will be deleted when
slave restarts, but it is a better intention to not delete them.
*/
- DBUG_PRINT("info", ("table: 0x%lx", (long) table));
- close_temporary(table, 1, 0);
+
+ free_table_share(share);
+ my_free(share);
}
- save_temporary_tables= 0;
- slave_open_temp_tables= 0;
+
+ save_temporary_tables.empty();
Is it needed?
you've popped all shares from the list, it's empty.
I'd rather add an assert instead
+
DBUG_VOID_RETURN;
}
diff --git a/sql/sql_class.h b/sql/sql_class.h
index ae240ae..a70c4a9 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -1247,6 +1247,61 @@ enum enum_locked_tables_mode
LTM_PRELOCKED_UNDER_LOCK_TABLES
};
+/**
+ The following structure is an extension to TABLE_SHARE and is
+ exclusively for temporary tables.
+
+ @note:
+ Although, TDC_element has data members (like next, prev &
+ all_tables) to store the list of TABLE_SHARE & TABLE objects
+ related to a particular TABLE_SHARE, they cannot be moved to
+ TABLE_SHARE in order to be reused for temporary tables. This
+ is because, as concurrent threads iterating through hash of
+ TDC_element's may need access to all_tables, but if all_tables
+ is made part of TABLE_SHARE, then TDC_element->share->all_tables
+ is not always guaranteed to be valid, as TDC_element can live
+ longer than TABLE_SHARE.
+*/
+struct TMP_TABLE_SHARE : public TABLE_SHARE
+{
+private:
+ /*
+ Link to all temporary table shares. Declared as private to
+ avoid direct manipulation with those objects. One should
+ use methods of I_P_List template instead.
+ */
+ TMP_TABLE_SHARE *tmp_next;
+ TMP_TABLE_SHARE **tmp_prev;
+
+ friend struct All_tmp_table_shares;
+
+public:
+ /*
+ Doubly-linked (back-linked) lists of used and unused TABLE objects
+ for this share.
and unused? you don't free them but keep in the list?
+ */
+ All_share_tables_list all_tmp_tables;
+};
+
+/**
+ Helper class which specifies which members of TMP_TABLE_SHARE are
+ used for participation in the list of temporary tables.
+*/
+
+struct All_tmp_table_shares
+{
+ static inline TMP_TABLE_SHARE **next_ptr(TMP_TABLE_SHARE *l)
+ {
+ return &l->tmp_next;
+ }
+ static inline TMP_TABLE_SHARE ***prev_ptr(TMP_TABLE_SHARE *l)
+ {
+ return &l->tmp_prev;
+ }
+};
+
+/* Also used in rpl_rli.h. */
+typedef I_P_List <TMP_TABLE_SHARE, All_tmp_table_shares> All_tmp_tables_list;
/**
Class that holds information about tables which were opened and locked
diff --git a/sql/temporary_tables.cc b/sql/temporary_tables.cc
new file mode 100644
index 0000000..1514b72
--- /dev/null
+++ b/sql/temporary_tables.cc
...
+TABLE *THD::find_temporary_table(const char *db,
+ const char *table_name)
+{
+ DBUG_ENTER("THD::find_temporary_table");
+
+ TABLE *table;
+ char key[MAX_DBKEY_LENGTH];
+ uint key_length;
+ bool locked;
+
+ if (!(has_temporary_tables() || (rgi_slave && has_slave_temporary_tables())))
hmm, really? you had here is_empty(true) before
and your is_empty() was working like this:
if (flag_is_true)
{ do rgi_slave }
else
{ do thd }
your old is_empty was not checking thd if the argument was true,
your new code does, as if your is_empty() was
do thd;
if (flag_is_true)
{ do rgi_slave}
+ {
+ DBUG_RETURN(NULL);
+ }
+
+ key_length= create_tmp_table_def_key(key, db, table_name);
Regards,
Sergei
Chief Architect MariaDB
and security@mariadb.org
Nirbhay Choubey
Sergei Golubchik