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MDEV-17613 MIN/MAX Optimization (Select tables optimized away) does n…

…ot work

Prune to now-partition when there is no FOR SYSTEM_TIME clause.
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midenok committed Dec 26, 2018
1 parent 43882e7 commit cdbac54df0bd857a053decd66b6067abf15a6801
@@ -546,6 +546,17 @@ t1 CREATE TABLE `t1` (
#
create or replace table t1 (f int) with system versioning partition by hash(f);
insert delayed into t1 values (1);
#
# MDEV-17613 MIN/MAX Optimization (Select tables optimized away) does not work
#
create or replace table t1 (pk int primary key) with system versioning
partition by system_time (
partition p1 history,
partition pn current);
insert into t1 values (1), (2);
explain select max(pk) from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
# Test cleanup
drop database test;
create database test;
@@ -44,7 +44,7 @@ i
6
explain partitions select * from t1;
id select_type table partitions type possible_keys key key_len ref rows Extra
1 SIMPLE t1 pn_pnsp0,pn_pnsp1 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t1 pn_pnsp0,pn_pnsp1 ALL NULL NULL NULL NULL 2
explain partitions select * from t1 for system_time as of '2001-02-04 10:20:30';
id select_type table partitions type possible_keys key key_len ref rows Extra
1 SIMPLE t1 p1_p1sp0,p1_p1sp1,p0_p0sp0,p0_p0sp1,p2_p2sp0,p2_p2sp1,pn_pnsp0,pn_pnsp1 ALL NULL NULL NULL NULL # Using where
@@ -497,6 +497,27 @@ create or replace table t1 (f int) with system versioning partition by hash(f);
--error 0,ER_DELAYED_NOT_SUPPORTED
insert delayed into t1 values (1);

--echo #
--echo # MDEV-17613 MIN/MAX Optimization (Select tables optimized away) does not work
--echo #
--disable_query_log
set @saved_storage_engine= @@default_storage_engine;
if ($MTR_COMBINATION_HEAP)
{
# This case does not work with HEAP
set default_storage_engine= myisam;
}
--enable_query_log
create or replace table t1 (pk int primary key) with system versioning
partition by system_time (
partition p1 history,
partition pn current);
insert into t1 values (1), (2);
explain select max(pk) from t1;
--disable_query_log
set default_storage_engine= @saved_storage_engine;
--enable_query_log

--echo # Test cleanup
drop database test;
create database test;
@@ -721,6 +721,19 @@ void vers_select_conds_t::print(String *str, enum_query_type query_type) const
}
}

/**
Setup System Versioning conditions
Add WHERE condition according to FOR SYSTEM_TIME clause.
If the table is partitioned by SYSTEM_TIME and there is no FOR SYSTEM_TIME
clause, then select now-partition instead of modifying WHERE condition.
@retval
-1 on error
@retval
0 on success
*/
int SELECT_LEX::vers_setup_conds(THD *thd, TABLE_LIST *tables)
{
DBUG_ENTER("SELECT_LEX::vers_setup_cond");
@@ -788,12 +801,13 @@ int SELECT_LEX::vers_setup_conds(THD *thd, TABLE_LIST *tables)
vers_select_conds_t &vers_conditions= table->vers_conditions;

#ifdef WITH_PARTITION_STORAGE_ENGINE
/*
if the history is stored in partitions, then partitions
themselves are not versioned
*/
if (table->partition_names && table->table->part_info->vers_info)
Vers_part_info *vers_info;
if (table->table->part_info && (vers_info= table->table->part_info->vers_info))
{
if (table->partition_names)
{
/* If the history is stored in partitions, then partitions
themselves are not versioned. */
if (vers_conditions.is_set())
{
my_error(ER_VERS_QUERY_IN_PARTITION, MYF(0), table->alias.str);
@@ -802,6 +816,16 @@ int SELECT_LEX::vers_setup_conds(THD *thd, TABLE_LIST *tables)
else
vers_conditions.init(SYSTEM_TIME_ALL);
}
else if (!vers_conditions.is_set())
{
table->partition_names= newx List<String>;
String *s= newx String(vers_info->now_part->partition_name,
system_charset_info);
table->partition_names->push_back(s);
table->table->file->change_partitions_to_open(table->partition_names);
vers_conditions.init(SYSTEM_TIME_ALL);
}
}
#endif

if (outer_table && !vers_conditions.is_set())
@@ -951,6 +975,7 @@ int SELECT_LEX::vers_setup_conds(THD *thd, TABLE_LIST *tables)
DBUG_RETURN(0);
#undef newx
}
#undef newx

/*****************************************************************************
Check fields, find best join, do the select and output fields.

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