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EXPLAIN FORMAT=JSON: support SJ-Materialization

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- Switch Explain data structure from "flat" representation of
  SJ-Materialization into nested one.
- Update functions that print tabular output to operate on the
  nested structure.
- Add function to generate JSON output.
This commit is contained in:
Sergei Petrunia
2014-12-01 21:35:31 +03:00
parent c46eadb2b3
commit 753718c201
6 changed files with 253 additions and 83 deletions
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75
sql/sql_explain.cc
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@ -602,7 +602,7 @@ void Explain_select::replace_table(uint idx, Explain_table_access *new_tab)
}
Explain_select::~Explain_select()
Explain_basic_join::~Explain_basic_join()
{
if (join_tabs)
{
@ -663,34 +663,77 @@ int Explain_select::print_explain(Explain_query *query,
using_fs= false;
}
}
for (uint i=0; i< n_join_tabs; i++)
{
Explain_basic_join* nest;
if ((nest= join_tabs[i]->sjm_nest))
nest->print_explain(query, output, explain_flags, is_analyze);
}
}
return print_explain_for_children(query, output, explain_flags, is_analyze);
}
int Explain_basic_join::print_explain(Explain_query *query,
select_result_sink *output,
uint8 explain_flags, bool is_analyze)
{
for (uint i=0; i< n_join_tabs; i++)
{
if (join_tabs[i]->print_explain(output, explain_flags, is_analyze,
select_id,
"MATERIALIZED" /*select_type*/,
FALSE /*using temporary*/,
FALSE /*using filesort*/))
return 1;
}
return 0;
}
void Explain_select::print_explain_json(Explain_query *query,
Json_writer *writer, bool is_analyze)
{
Json_writer_nesting_guard guard(writer);
writer->add_member("query_block").start_object();
writer->add_member("select_id").add_ll(select_id);
if (message)
{
writer->add_member("query_block").start_object();
writer->add_member("select_id").add_ll(select_id);
writer->add_member("table").start_object();
writer->add_member("message").add_str(message);
writer->end_object();
print_explain_json_for_children(query, writer, is_analyze);
writer->end_object();
}
else
{
for (uint i=0; i< n_join_tabs; i++)
{
// psergey-todo: Need to honor SJM nests...
join_tabs[i]->print_explain_json(query, writer, is_analyze);
}
/*
TODO: how does this approach allow to print ORDER BY members?
Explain_basic_join does not have ORDER/GROUP.
A: factor out join tab printing loop into a common func.
*/
Explain_basic_join::print_explain_json(query, writer, is_analyze);
}
}
void Explain_basic_join::print_explain_json(Explain_query *query,
Json_writer *writer,
bool is_analyze)
{
Json_writer_nesting_guard guard(writer);
writer->add_member("query_block").start_object();
writer->add_member("select_id").add_ll(select_id);
for (uint i=0; i< n_join_tabs; i++)
{
join_tabs[i]->print_explain_json(query, writer, is_analyze);
}
print_explain_json_for_children(query, writer, is_analyze);
writer->end_object();
}
@ -837,17 +880,11 @@ int Explain_table_access::print_explain(select_result_sink *output, uint8 explai
List<Item> item_list;
Item *item_null= new Item_null();
if (sjm_nest_select_id)
select_id= sjm_nest_select_id;
/* `id` column */
item_list.push_back(new Item_int((int32) select_id));
/* `select_type` column */
if (sjm_nest_select_id)
push_str(&item_list, "MATERIALIZED");
else
push_str(&item_list, select_type);
push_str(&item_list, select_type);
/* `table` column */
push_string(&item_list, &table_name);
@ -1242,6 +1279,14 @@ void Explain_table_access::print_explain_json(Explain_query *query,
node->print_explain_json(query, writer, is_analyze);
writer->end_object();
}
if (sjm_nest)
{
/* This is a non-merged semi-join table. Print its contents here */
writer->add_member("materialized").start_object();
writer->add_member("unique").add_ll(1);
sjm_nest->print_explain_json(query, writer, is_analyze);
writer->end_object();
}
writer->end_object();
}