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Apply earlier patch: correct handling of subqueries that

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were not yet optimized or already executed and deleted.
This commit is contained in:
Sergey Petrunya
2012-01-04 04:57:01 +04:00
parent b01348879d
commit ee40ee9cb8
5 changed files with 150 additions and 49 deletions
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29
mysql-test/r/show_explain.result
View File

@@ -15,7 +15,7 @@ ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EX
show explain for $thr1; show explain for $thr1;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
set @show_explain_probe_select_id=1; set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
select count(*) from t1 where a < 100000; select count(*) from t1 where a < 100000;
show explain for $thr2; show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra id select_type table type possible_keys key key_len ref rows Extra
@@ -25,7 +25,7 @@ count(*)
select max(c) from t1 where a < 10; select max(c) from t1 where a < 10;
show explain for $thr2; show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 5 NULL 10 Using where 1 SIMPLE t1 range a a 5 NULL 10 Using index condition
max(c) max(c)
9 9
# We can catch EXPLAIN, too. # We can catch EXPLAIN, too.
@@ -40,7 +40,7 @@ id select_type table type possible_keys key key_len ref rows Extra
set optimizer_switch= @show_expl_tmp; set optimizer_switch= @show_expl_tmp;
# UNION, first branch # UNION, first branch
set @show_explain_probe_select_id=1; set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
explain select a from t0 A union select a+1 from t0 B; explain select a from t0 A union select a+1 from t0 B;
show explain for $thr2; show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra id select_type table type possible_keys key key_len ref rows Extra
@@ -53,7 +53,7 @@ id select_type table type possible_keys key key_len ref rows Extra
NULL UNION RESULT <union1,2> ALL NULL NULL NULL NULL NULL NULL UNION RESULT <union1,2> ALL NULL NULL NULL NULL NULL
# UNION, second branch # UNION, second branch
set @show_explain_probe_select_id=1; set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
explain select a from t0 A union select a+1 from t0 B; explain select a from t0 A union select a+1 from t0 B;
show explain for $thr2; show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra id select_type table type possible_keys key key_len ref rows Extra
@@ -66,7 +66,7 @@ id select_type table type possible_keys key key_len ref rows Extra
NULL UNION RESULT <union1,2> ALL NULL NULL NULL NULL NULL NULL UNION RESULT <union1,2> ALL NULL NULL NULL NULL NULL
# Uncorrelated subquery, select # Uncorrelated subquery, select
set @show_explain_probe_select_id=1; set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
select a, (select max(a) from t0 B) from t0 A where a<1; select a, (select max(a) from t0 B) from t0 A where a<1;
show explain for $thr2; show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra id select_type table type possible_keys key key_len ref rows Extra
@@ -76,7 +76,7 @@ a (select max(a) from t0 B)
0 9 0 9
# Uncorrelated subquery, explain # Uncorrelated subquery, explain
set @show_explain_probe_select_id=1; set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
explain select a, (select max(a) from t0 B) from t0 A where a<1; explain select a, (select max(a) from t0 B) from t0 A where a<1;
show explain for $thr2; show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra id select_type table type possible_keys key key_len ref rows Extra
@@ -87,7 +87,7 @@ id select_type table type possible_keys key key_len ref rows Extra
2 SUBQUERY B ALL NULL NULL NULL NULL 10 2 SUBQUERY B ALL NULL NULL NULL NULL 10
# correlated subquery, select # correlated subquery, select
set @show_explain_probe_select_id=1; set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1; select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
show explain for $thr2; show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra id select_type table type possible_keys key key_len ref rows Extra
@@ -97,7 +97,7 @@ a (select max(a) from t0 b where b.a+a.a<10)
0 9 0 9
# correlated subquery, explain # correlated subquery, explain
set @show_explain_probe_select_id=1; set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1; select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
show explain for $thr2; show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra id select_type table type possible_keys key key_len ref rows Extra
@@ -107,7 +107,7 @@ a (select max(a) from t0 b where b.a+a.a<10)
0 9 0 9
# correlated subquery, select, while inside the subquery # correlated subquery, select, while inside the subquery
set @show_explain_probe_select_id=2; set @show_explain_probe_select_id=2;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1; select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
show explain for $thr2; show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra id select_type table type possible_keys key key_len ref rows Extra
@@ -117,7 +117,7 @@ a (select max(a) from t0 b where b.a+a.a<10)
0 9 0 9
# correlated subquery, explain, while inside the subquery # correlated subquery, explain, while inside the subquery
set @show_explain_probe_select_id=2; set @show_explain_probe_select_id=2;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1; select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
show explain for $thr2; show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra id select_type table type possible_keys key key_len ref rows Extra
@@ -125,4 +125,13 @@ id select_type table type possible_keys key key_len ref rows Extra
2 DEPENDENT SUBQUERY b ALL NULL NULL NULL NULL 10 Using where 2 DEPENDENT SUBQUERY b ALL NULL NULL NULL NULL 10 Using where
a (select max(a) from t0 b where b.a+a.a<10) a (select max(a) from t0 b where b.a+a.a<10)
0 9 0 9
# correlated subquery, explain, while inside the subquery
set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_join_exec_end';
select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Query plan already deleted
a (select max(a) from t0 b where b.a+a.a<10)
0 9
drop table t0,t1; drop table t0,t1;

37
mysql-test/t/show_explain.test
View File

@@ -12,17 +12,17 @@ drop table if exists t0, t1;
# is that we use the following commands for synchronization: # is that we use the following commands for synchronization:
# #
# set @show_explain_probe_select_id=1; # set @show_explain_probe_select_id=1;
# set debug='d,show_explain_probe_1'; # set debug='d,show_explain_probe_join_exec_start';
# send select count(*) from t1 where a < 100000; # send select count(*) from t1 where a < 100000;
# #
# When ran with mysqltest_embedded, this translates into: # When ran with mysqltest_embedded, this translates into:
# #
# Thread1> DBUG_PUSH("d,show_explain_probe_1"); # Thread1> DBUG_PUSH("d,show_explain_probe_join_exec_start");
# Thread1> create another thread for doing "send ... reap" # Thread1> create another thread for doing "send ... reap"
# Thread2> mysql_parse("select count(*) from t1 where a < 100000"); # Thread2> mysql_parse("select count(*) from t1 where a < 100000");
# #
# That is, "select count(*) ..." is ran in a thread for which DBUG_PUSH(...) # That is, "select count(*) ..." is ran in a thread for which DBUG_PUSH(...)
# has not been called. As a result, show_explain_probe_1 does not fire, and # has not been called. As a result, show_explain_probe_join_exec_start does not fire, and
# "select count(*) ..." does not wait till its SHOW EXPLAIN command, and the # "select count(*) ..." does not wait till its SHOW EXPLAIN command, and the
# test fails. # test fails.
# #
@@ -70,7 +70,7 @@ let $wait_condition= select State='show_explain_trap' from information_schema.pr
# #
connection con1; connection con1;
set @show_explain_probe_select_id=1; set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
send select count(*) from t1 where a < 100000; send select count(*) from t1 where a < 100000;
connection default; connection default;
@@ -102,7 +102,7 @@ set optimizer_switch= @show_expl_tmp;
--echo # UNION, first branch --echo # UNION, first branch
set @show_explain_probe_select_id=1; set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
send explain select a from t0 A union select a+1 from t0 B; send explain select a from t0 A union select a+1 from t0 B;
connection default; connection default;
--source include/wait_condition.inc --source include/wait_condition.inc
@@ -113,7 +113,7 @@ reap;
--echo # UNION, second branch --echo # UNION, second branch
set @show_explain_probe_select_id=1; set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
send explain select a from t0 A union select a+1 from t0 B; send explain select a from t0 A union select a+1 from t0 B;
connection default; connection default;
--source include/wait_condition.inc --source include/wait_condition.inc
@@ -124,7 +124,7 @@ reap;
--echo # Uncorrelated subquery, select --echo # Uncorrelated subquery, select
set @show_explain_probe_select_id=1; set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
send select a, (select max(a) from t0 B) from t0 A where a<1; send select a, (select max(a) from t0 B) from t0 A where a<1;
connection default; connection default;
--source include/wait_condition.inc --source include/wait_condition.inc
@@ -135,7 +135,7 @@ reap;
--echo # Uncorrelated subquery, explain --echo # Uncorrelated subquery, explain
set @show_explain_probe_select_id=1; set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
send explain select a, (select max(a) from t0 B) from t0 A where a<1; send explain select a, (select max(a) from t0 B) from t0 A where a<1;
connection default; connection default;
--source include/wait_condition.inc --source include/wait_condition.inc
@@ -145,7 +145,7 @@ reap;
--echo # correlated subquery, select --echo # correlated subquery, select
set @show_explain_probe_select_id=1; set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1; send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
connection default; connection default;
--source include/wait_condition.inc --source include/wait_condition.inc
@@ -155,7 +155,7 @@ reap;
--echo # correlated subquery, explain --echo # correlated subquery, explain
set @show_explain_probe_select_id=1; set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1; send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
connection default; connection default;
--source include/wait_condition.inc --source include/wait_condition.inc
@@ -165,7 +165,7 @@ reap;
--echo # correlated subquery, select, while inside the subquery --echo # correlated subquery, select, while inside the subquery
set @show_explain_probe_select_id=2; # <--- set @show_explain_probe_select_id=2; # <---
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1; send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
connection default; connection default;
--source include/wait_condition.inc --source include/wait_condition.inc
@@ -175,7 +175,7 @@ reap;
--echo # correlated subquery, explain, while inside the subquery --echo # correlated subquery, explain, while inside the subquery
set @show_explain_probe_select_id=2; set @show_explain_probe_select_id=2;
set debug='d,show_explain_probe_1'; set debug='d,show_explain_probe_join_exec_start';
send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1; send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
connection default; connection default;
--source include/wait_condition.inc --source include/wait_condition.inc
@@ -184,6 +184,16 @@ connection con1;
reap; reap;
--echo # correlated subquery, explain, while inside the subquery
set @show_explain_probe_select_id=1;
set debug='d,show_explain_probe_join_exec_end';
send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
# TODO: explain in the parent subuqery when the un-correlated child has been # TODO: explain in the parent subuqery when the un-correlated child has been
# run (and have done irreversible cleanups) # run (and have done irreversible cleanups)
@@ -195,4 +205,7 @@ reap;
## TODO: Test this: have several SHOW EXPLAIN requests be queued up for a ## TODO: Test this: have several SHOW EXPLAIN requests be queued up for a
## thread and served together. ## thread and served together.
## TODO: SHOW EXPLAIN while the primary query is running EXPLAIN EXTENDED/PARTITIONS
##
drop table t0,t1; drop table t0,t1;

40
sql/sql_lex.cc
View File

@@ -3555,16 +3555,11 @@ void st_select_lex::set_explain_type(bool on_the_fly)
using_materialization= TRUE; using_materialization= TRUE;
} }
if (this == master_unit()->fake_select_lex)
type= "UNION RESULT";
if (&master_unit()->thd->lex->select_lex == this) if (&master_unit()->thd->lex->select_lex == this)
{ {
type= is_primary ? "PRIMARY" : "SIMPLE"; type= is_primary ? "PRIMARY" : "SIMPLE";
} }
else
if (!on_the_fly)
// else
{ {
if (this == first) if (this == first)
{ {
@@ -3594,9 +3589,14 @@ void st_select_lex::set_explain_type(bool on_the_fly)
else else
{ {
type= is_uncacheable ? "UNCACHEABLE UNION": "UNION"; type= is_uncacheable ? "UNCACHEABLE UNION": "UNION";
if (this == master_unit()->fake_select_lex)
type= "UNION RESULT";
} }
} }
} }
if (!on_the_fly)
options|= SELECT_DESCRIBE; options|= SELECT_DESCRIBE;
} }
@@ -3744,10 +3744,17 @@ bool st_select_lex::is_merged_child_of(st_select_lex *ancestor)
} }
int print_explain_message_line(select_result_sink *result,
SELECT_LEX *select_lex,
bool on_the_fly,
uint8 options,
const char *message);
int st_select_lex::print_explain(select_result_sink *output) int st_select_lex::print_explain(select_result_sink *output)
{ {
int res; int res;
if (join && join->optimized == 2) if (join && join->have_query_plan == JOIN::QEP_AVAILABLE)
{ {
res= join->print_explain(output, TRUE, res= join->print_explain(output, TRUE,
FALSE, // need_tmp_table, FALSE, // need_tmp_table,
@@ -3773,13 +3780,18 @@ int st_select_lex::print_explain(select_result_sink *output)
} }
else else
{ {
/* Produce "not yet optimized" line */ const char *msg;
const char *msg="Not yet optimized"; if (!join)
res= join->print_explain(output, TRUE, DBUG_ASSERT(0); // psergey: TODO: can this happen or not?
FALSE, // need_tmp_table, if (join->have_query_plan == JOIN::QEP_NOT_PRESENT_YET)
FALSE, // bool need_order, msg= "Not yet optimized";
FALSE, // bool distinct, else
msg); //const char *message {
DBUG_ASSERT(join->have_query_plan == JOIN::QEP_DELETED);
msg= "Query plan already deleted";
}
res= print_explain_message_line(output, this, TRUE /* on_the_fly */,
0, msg);
} }
err: err:
return 0; return 0;

86
sql/sql_select.cc
View File

@@ -931,7 +931,8 @@ err:
int JOIN::optimize() int JOIN::optimize()
{ {
int res= optimize_inner(); int res= optimize_inner();
optimized= 2; if (!res)
have_query_plan= QEP_AVAILABLE;
return res; return res;
} }
/** /**
@@ -2104,7 +2105,22 @@ void JOIN::exec()
Enable SHOW EXPLAIN only if we're in the top-level query. Enable SHOW EXPLAIN only if we're in the top-level query.
*/ */
thd->apc_target.enable(); thd->apc_target.enable();
DBUG_EXECUTE_IF("show_explain_probe_join_exec_start",
if (dbug_user_var_equals_int(thd,
"show_explain_probe_select_id",
select_lex->select_number))
dbug_serve_apcs(thd, 1);
);
exec_inner(); exec_inner();
DBUG_EXECUTE_IF("show_explain_probe_join_exec_end",
if (dbug_user_var_equals_int(thd,
"show_explain_probe_select_id",
select_lex->select_number))
dbug_serve_apcs(thd, 1);
);
thd->apc_target.disable(); thd->apc_target.disable();
} }
@@ -2127,13 +2143,6 @@ void JOIN::exec_inner()
int tmp_error; int tmp_error;
DBUG_ENTER("JOIN::exec"); DBUG_ENTER("JOIN::exec");
DBUG_EXECUTE_IF("show_explain_probe_1",
if (dbug_user_var_equals_int(thd,
"show_explain_probe_select_id",
select_lex->select_number))
dbug_serve_apcs(thd, 1);
);
thd_proc_info(thd, "executing"); thd_proc_info(thd, "executing");
error= 0; error= 0;
if (procedure) if (procedure)
@@ -2421,9 +2430,17 @@ void JOIN::exec_inner()
DBUG_PRINT("info",("Creating group table")); DBUG_PRINT("info",("Creating group table"));
/* Free first data from old join */ /* Free first data from old join */
fprintf(stderr,"Q: %s\n", thd->query());
//DBUG_ASSERT(0);
/*
psergey-todo: this is the place of pre-mature JOIN::free call.
*/
curr_join->join_free(); curr_join->join_free();
//psergey-todo: SHOW EXPLAIN probe here
if (curr_join->make_simple_join(this, curr_tmp_table)) if (curr_join->make_simple_join(this, curr_tmp_table))
DBUG_VOID_RETURN; DBUG_VOID_RETURN;
//psergey-todo: SHOW EXPLAIN probe here
calc_group_buffer(curr_join, group_list); calc_group_buffer(curr_join, group_list);
count_field_types(select_lex, &curr_join->tmp_table_param, count_field_types(select_lex, &curr_join->tmp_table_param,
curr_join->tmp_all_fields1, curr_join->tmp_all_fields1,
@@ -2544,7 +2561,9 @@ void JOIN::exec_inner()
if (curr_tmp_table->distinct) if (curr_tmp_table->distinct)
curr_join->select_distinct=0; /* Each row is unique */ curr_join->select_distinct=0; /* Each row is unique */
//psergey-todo: SHOW EXPLAIN probe here
curr_join->join_free(); /* Free quick selects */ curr_join->join_free(); /* Free quick selects */
//psergey-todo: SHOW EXPLAIN probe here
if (curr_join->select_distinct && ! curr_join->group_list) if (curr_join->select_distinct && ! curr_join->group_list)
{ {
thd_proc_info(thd, "Removing duplicates"); thd_proc_info(thd, "Removing duplicates");
@@ -10114,6 +10133,7 @@ void JOIN::cleanup(bool full)
DBUG_ENTER("JOIN::cleanup"); DBUG_ENTER("JOIN::cleanup");
DBUG_PRINT("enter", ("full %u", (uint) full)); DBUG_PRINT("enter", ("full %u", (uint) full));
have_query_plan= QEP_DELETED;
if (table) if (table)
{ {
JOIN_TAB *tab; JOIN_TAB *tab;
@@ -20706,6 +20726,41 @@ void JOIN::clear()
} }
/*
Print an EXPLAIN line with all NULLs and given message in the 'Extra' column
*/
int print_explain_message_line(select_result_sink *result,
SELECT_LEX *select_lex,
bool on_the_fly,
uint8 options,
const char *message)
{
const CHARSET_INFO *cs= system_charset_info;
Item *item_null= new Item_null();
List<Item> item_list;
if (on_the_fly)
select_lex->set_explain_type(on_the_fly);
item_list.push_back(new Item_int((int32)
select_lex->select_number));
item_list.push_back(new Item_string(select_lex->type,
strlen(select_lex->type), cs));
for (uint i=0 ; i < 7; i++)
item_list.push_back(item_null);
if (options & DESCRIBE_PARTITIONS)
item_list.push_back(item_null);
if (options & DESCRIBE_EXTENDED)
item_list.push_back(item_null);
item_list.push_back(new Item_string(message,strlen(message),cs));
if (result->send_data(item_list))
return 1;
return 0;
}
int print_fake_select_lex_join(select_result_sink *result, bool on_the_fly, int print_fake_select_lex_join(select_result_sink *result, bool on_the_fly,
SELECT_LEX *select_lex, uint8 select_options) SELECT_LEX *select_lex, uint8 select_options)
{ {
@@ -20810,7 +20865,7 @@ int JOIN::print_explain(select_result_sink *result, bool on_the_fly,
DBUG_PRINT("info", ("Select 0x%lx, type %s, message %s", DBUG_PRINT("info", ("Select 0x%lx, type %s, message %s",
(ulong)join->select_lex, join->select_lex->type, (ulong)join->select_lex, join->select_lex->type,
message ? message : "NULL")); message ? message : "NULL"));
DBUG_ASSERT(this->optimized == 2); DBUG_ASSERT(this->have_query_plan == QEP_AVAILABLE);
/* Don't log this into the slow query log */ /* Don't log this into the slow query log */
if (!on_the_fly) if (!on_the_fly)
@@ -20825,7 +20880,9 @@ int JOIN::print_explain(select_result_sink *result, bool on_the_fly,
*/ */
if (message) if (message)
{ {
item_list.push_back(new Item_int((int32) // join->thd->lex->describe <- as options
#if 0
item_list.push_bace(new Item_int((int32)
join->select_lex->select_number)); join->select_lex->select_number));
item_list.push_back(new Item_string(join->select_lex->type, item_list.push_back(new Item_string(join->select_lex->type,
strlen(join->select_lex->type), cs)); strlen(join->select_lex->type), cs));
@@ -20839,9 +20896,16 @@ int JOIN::print_explain(select_result_sink *result, bool on_the_fly,
item_list.push_back(new Item_string(message,strlen(message),cs)); item_list.push_back(new Item_string(message,strlen(message),cs));
if (result->send_data(item_list)) if (result->send_data(item_list))
error= 1; error= 1;
#endif
//psergey-todo: is passing join->thd->lex->describe correct for SHOW EXPLAIN?
if (print_explain_message_line(result, join->select_lex, on_the_fly,
join->thd->lex->describe, message))
error= 1;
} }
else if (join->select_lex == join->unit->fake_select_lex) else if (join->select_lex == join->unit->fake_select_lex)
{ {
//psergey-todo: is passing join->thd->lex->describe correct for SHOW EXPLAIN?
if (print_fake_select_lex_join(result, on_the_fly, if (print_fake_select_lex_join(result, on_the_fly,
join->select_lex, join->select_lex,
join->thd->lex->describe)) join->thd->lex->describe))
@@ -20853,7 +20917,7 @@ int JOIN::print_explain(select_result_sink *result, bool on_the_fly,
table_map used_tables=0; table_map used_tables=0;
//if (!join->select_lex->type) //if (!join->select_lex->type)
if (on_the_fly) if (on_the_fly)
join->select_lex->set_explain_type(on_the_fly); //psergey-todo: this adds SELECT_DESCRIBE to options! bad for on-the-fly join->select_lex->set_explain_type(on_the_fly);
bool printing_materialize_nest= FALSE; bool printing_materialize_nest= FALSE;
uint select_id= join->select_lex->select_number; uint select_id= join->select_lex->select_number;

5
sql/sql_select.h
View File

@@ -1137,9 +1137,11 @@ public:
const char *zero_result_cause; ///< not 0 if exec must return zero result const char *zero_result_cause; ///< not 0 if exec must return zero result
bool union_part; ///< this subselect is part of union bool union_part; ///< this subselect is part of union
int optimized; ///< flag to avoid double optimization in EXPLAIN bool optimized; ///< flag to avoid double optimization in EXPLAIN
bool initialized; ///< flag to avoid double init_execution calls bool initialized; ///< flag to avoid double init_execution calls
enum { QEP_NOT_PRESENT_YET, QEP_AVAILABLE, QEP_DELETED} have_query_plan;
/* /*
Additional WHERE and HAVING predicates to be considered for IN=>EXISTS Additional WHERE and HAVING predicates to be considered for IN=>EXISTS
subquery transformation of a JOIN object. subquery transformation of a JOIN object.
@@ -1221,6 +1223,7 @@ public:
ref_pointer_array_size= 0; ref_pointer_array_size= 0;
zero_result_cause= 0; zero_result_cause= 0;
optimized= 0; optimized= 0;
have_query_plan= QEP_NOT_PRESENT_YET;
initialized= 0; initialized= 0;
cond_equal= 0; cond_equal= 0;
having_equal= 0; having_equal= 0;