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Add support for semi-join strategies: FirstMatch, DuplicateWeedout,
LooseScan.
This commit is contained in:
Sergei Petrunia
2014-12-02 01:40:10 +03:00
parent a35b05399e
commit 0000695025
5 changed files with 123 additions and 3 deletions
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23
sql/sql_explain.cc
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@ -732,7 +732,13 @@ void Explain_basic_join::print_explain_json(Explain_query *query,
writer->add_member("select_id").add_ll(select_id);
for (uint i=0; i< n_join_tabs; i++)
{
if (join_tabs[i]->start_dups_weedout)
writer->add_member("duplicates_removal").start_object();
join_tabs[i]->print_explain_json(query, writer, is_analyze);
if (join_tabs[i]->end_dups_weedout)
writer->end_object();
}
print_explain_json_for_children(query, writer, is_analyze);
writer->end_object();
@ -1089,9 +1095,7 @@ void Explain_table_access::tag_to_json(Json_writer *writer, enum explain_extra_t
write_item(writer, pushed_index_cond);
break;
case ET_USING_WHERE:
if (where_cond)
{
writer->add_member("attached_condition");
/*
We are printing the condition that is checked when scanning this
table.
@ -1099,7 +1103,11 @@ void Explain_table_access::tag_to_json(Json_writer *writer, enum explain_extra_t
- in other cases, it is where_cond.
*/
Item *item= bka_type.is_using_jbuf()? cache_cond: where_cond;
write_item(writer, item);
if (item)
{
writer->add_member("attached_condition");
write_item(writer, item);
}
}
break;
case ET_USING_INDEX:
@ -1110,6 +1118,15 @@ void Explain_table_access::tag_to_json(Json_writer *writer, enum explain_extra_t
break;
case ET_USING_JOIN_BUFFER:
/* Do nothing. Join buffer is handled differently */
case ET_START_TEMPORARY:
case ET_END_TEMPORARY:
/* Handled as "duplicates_removal: { ... } */
break;
case ET_FIRST_MATCH:
writer->add_member("first_match").add_str(firstmatch_table_name.c_ptr());
break;
case ET_LOOSESCAN:
writer->add_member("loose_scan").add_bool(true);
break;
default:
DBUG_ASSERT(0);