/* Copyright (c) 2013 Monty Program Ab This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */ #ifdef USE_PRAGMA_IMPLEMENTATION #pragma implementation // gcc: Class implementation #endif #include "mariadb.h" #include "sql_priv.h" #include "sql_select.h" #include "my_json_writer.h" #include "opt_range.h" #include "sql_expression_cache.h" const char * STR_DELETING_ALL_ROWS= "Deleting all rows"; const char * STR_IMPOSSIBLE_WHERE= "Impossible WHERE"; const char * STR_NO_ROWS_AFTER_PRUNING= "No matching rows after partition pruning"; const char *unit_operation_text[4]= { "UNIT RESULT","UNION RESULT","INTERSECT RESULT","EXCEPT RESULT" }; const char *pushed_derived_text= "PUSHED DERIVED"; const char *pushed_select_text= "PUSHED SELECT"; static void write_item(Json_writer *writer, Item *item); static void append_item_to_str(String *out, Item *item); Explain_query::Explain_query(THD *thd_arg, MEM_ROOT *root) : mem_root(root), upd_del_plan(NULL), insert_plan(NULL), unions(root), selects(root), thd(thd_arg), apc_enabled(false), operations(0) { } static void print_json_array(Json_writer *writer, const char *title, String_list &list) { List_iterator_fast it(list); const char *name; writer->add_member(title).start_array(); while ((name= it++)) writer->add_str(name); writer->end_array(); } Explain_query::~Explain_query() { if (apc_enabled) thd->apc_target.disable(); delete upd_del_plan; delete insert_plan; uint i; for (i= 0 ; i < unions.elements(); i++) delete unions.at(i); for (i= 0 ; i < selects.elements(); i++) delete selects.at(i); } Explain_node *Explain_query::get_node(uint select_id) { Explain_union *u; if ((u= get_union(select_id))) return u; else return get_select(select_id); } Explain_union *Explain_query::get_union(uint select_id) { return (unions.elements() > select_id) ? unions.at(select_id) : NULL; } Explain_select *Explain_query::get_select(uint select_id) { return (selects.elements() > select_id) ? selects.at(select_id) : NULL; } void Explain_query::add_node(Explain_node *node) { uint select_id; operations++; if (node->get_type() == Explain_node::EXPLAIN_UNION) { Explain_union *u= (Explain_union*)node; select_id= u->get_select_id(); if (unions.elements() <= select_id) unions.resize(MY_MAX(select_id+1, unions.elements()*2), NULL); Explain_union *old_node; if ((old_node= get_union(select_id))) delete old_node; unions.at(select_id)= u; } else { Explain_select *sel= (Explain_select*)node; if (sel->select_id == FAKE_SELECT_LEX_ID) { DBUG_ASSERT(0); // this is a "fake select" from a UNION. } else { select_id= sel->select_id; Explain_select *old_node; if (selects.elements() <= select_id) selects.resize(MY_MAX(select_id+1, selects.elements()*2), NULL); if ((old_node= get_select(select_id))) delete old_node; selects.at(select_id)= sel; } } } void Explain_query::add_insert_plan(Explain_insert *insert_plan_arg) { insert_plan= insert_plan_arg; query_plan_ready(); } void Explain_query::add_upd_del_plan(Explain_update *upd_del_plan_arg) { upd_del_plan= upd_del_plan_arg; query_plan_ready(); } void Explain_query::query_plan_ready() { if (!apc_enabled) thd->apc_target.enable(); apc_enabled= true; } /* Send EXPLAIN output to the client. */ int Explain_query::send_explain(THD *thd) { select_result *result; LEX *lex= thd->lex; if (!(result= new (thd->mem_root) select_send(thd)) || thd->send_explain_fields(result, lex->describe, lex->analyze_stmt)) return 1; int res= 0; if (thd->lex->explain_json) print_explain_json(result, thd->lex->analyze_stmt); else res= print_explain(result, lex->describe, thd->lex->analyze_stmt); if (res) result->abort_result_set(); else result->send_eof(); return res; } /* The main entry point to print EXPLAIN of the entire query */ int Explain_query::print_explain(select_result_sink *output, uint8 explain_flags, bool is_analyze) { if (upd_del_plan) { upd_del_plan->print_explain(this, output, explain_flags, is_analyze); return 0; } else if (insert_plan) { insert_plan->print_explain(this, output, explain_flags, is_analyze); return 0; } else { /* Start printing from node with id=1 */ Explain_node *node= get_node(1); if (!node) return 1; /* No query plan */ return node->print_explain(this, output, explain_flags, is_analyze); } } void Explain_query::print_explain_json(select_result_sink *output, bool is_analyze) { Json_writer writer; writer.start_object(); if (upd_del_plan) upd_del_plan->print_explain_json(this, &writer, is_analyze); else if (insert_plan) insert_plan->print_explain_json(this, &writer, is_analyze); else { /* Start printing from node with id=1 */ Explain_node *node= get_node(1); if (!node) return; /* No query plan */ node->print_explain_json(this, &writer, is_analyze); } writer.end_object(); CHARSET_INFO *cs= system_charset_info; List item_list; const String *buf= writer.output.get_string(); item_list.push_back(new (thd->mem_root) Item_string(thd, buf->ptr(), buf->length(), cs), thd->mem_root); output->send_data(item_list); } bool print_explain_for_slow_log(LEX *lex, THD *thd, String *str) { return lex->explain->print_explain_str(thd, str, /*is_analyze*/ true); } /* Return tabular EXPLAIN output as a text string */ bool Explain_query::print_explain_str(THD *thd, String *out_str, bool is_analyze) { List fields; thd->make_explain_field_list(fields, thd->lex->describe, is_analyze); select_result_text_buffer output_buf(thd); output_buf.send_result_set_metadata(fields, thd->lex->describe); if (print_explain(&output_buf, thd->lex->describe, is_analyze)) return true; output_buf.save_to(out_str); return false; } static void push_str(THD *thd, List *item_list, const char *str) { item_list->push_back(new (thd->mem_root) Item_string_sys(thd, str), thd->mem_root); } static void push_string(THD *thd, List *item_list, String *str) { item_list->push_back(new (thd->mem_root) Item_string_sys(thd, str->ptr(), str->length()), thd->mem_root); } static void push_string_list(THD *thd, List *item_list, String_list &lines, String *buf) { List_iterator_fast it(lines); char *line; bool first= true; while ((line= it++)) { if (first) first= false; else buf->append(','); buf->append(line); } push_string(thd, item_list, buf); } /* Print an EXPLAIN output row, based on information provided in the parameters @note Parameters that may have NULL value in EXPLAIN output, should be passed (char*)NULL. @return 0 - OK 1 - OOM Error */ static int print_explain_row(select_result_sink *result, uint8 options, bool is_analyze, uint select_number, const char *select_type, const char *table_name, const char *partitions, enum join_type jtype, String_list *possible_keys, const char *index, const char *key_len, const char *ref, ha_rows *rows, double *r_rows, double r_filtered, const char *extra) { THD *thd= result->thd; MEM_ROOT *mem_root= thd->mem_root; Item *item_null= new (mem_root) Item_null(thd); List item_list; Item *item; if (!select_type[0]) return 0; item_list.push_back(new (mem_root) Item_int(thd, (int32) select_number), mem_root); item_list.push_back(new (mem_root) Item_string_sys(thd, select_type), mem_root); item_list.push_back(new (mem_root) Item_string_sys(thd, table_name), mem_root); if (options & DESCRIBE_PARTITIONS) { if (partitions) { item_list.push_back(new (mem_root) Item_string_sys(thd, partitions), mem_root); } else item_list.push_back(item_null, mem_root); } const char *jtype_str= join_type_str[jtype]; item_list.push_back(new (mem_root) Item_string_sys(thd, jtype_str), mem_root); /* 'possible_keys' The buffer must not be deallocated before we call send_data, otherwise we may end up reading freed memory. */ StringBuffer<64> possible_keys_buf; if (possible_keys && !possible_keys->is_empty()) { push_string_list(thd, &item_list, *possible_keys, &possible_keys_buf); } else item_list.push_back(item_null, mem_root); /* 'index */ item= index ? new (mem_root) Item_string_sys(thd, index) : item_null; item_list.push_back(item, mem_root); /* 'key_len */ item= key_len ? new (mem_root) Item_string_sys(thd, key_len) : item_null; item_list.push_back(item, mem_root); /* 'ref' */ item= ref ? new (mem_root) Item_string_sys(thd, ref) : item_null; item_list.push_back(item, mem_root); /* 'rows' */ StringBuffer<64> rows_str; if (rows) { rows_str.append_ulonglong((ulonglong)(*rows)); item_list.push_back(new (mem_root) Item_string_sys(thd, rows_str.ptr(), rows_str.length()), mem_root); } else item_list.push_back(item_null, mem_root); /* 'r_rows' */ StringBuffer<64> r_rows_str; if (is_analyze) { if (r_rows) { Item_float *fl= new (mem_root) Item_float(thd, *r_rows, 2); String tmp; String *res= fl->val_str(&tmp); r_rows_str.append(res->ptr()); item_list.push_back(new (mem_root) Item_string_sys(thd, r_rows_str.ptr(), r_rows_str.length()), mem_root); } else item_list.push_back(item_null, mem_root); } /* 'filtered' */ const double filtered=100.0; if (options & DESCRIBE_EXTENDED || is_analyze) item_list.push_back(new (mem_root) Item_float(thd, filtered, 2), mem_root); /* 'r_filtered' */ if (is_analyze) item_list.push_back(new (mem_root) Item_float(thd, r_filtered, 2), mem_root); /* 'Extra' */ if (extra) item_list.push_back(new (mem_root) Item_string_sys(thd, extra), mem_root); else item_list.push_back(item_null, mem_root); if (result->send_data(item_list)) return 1; return 0; } uint Explain_union::make_union_table_name(char *buf) { uint childno= 0; uint len, lastop= 0; LEX_CSTRING type; switch (operation) { case OP_MIX: lex_string_set3(&type, STRING_WITH_LEN("= NAME_LEN) { memcpy(buf + len, STRING_WITH_LEN("...>") + 1); len+= 4; } else { len+= lastop; buf[len - 1]= '>'; // change ',' to '>' } return len; } int Explain_union::print_explain(Explain_query *query, select_result_sink *output, uint8 explain_flags, bool is_analyze) { THD *thd= output->thd; MEM_ROOT *mem_root= thd->mem_root; char table_name_buffer[SAFE_NAME_LEN]; /* print all UNION children, in order */ for (int i= 0; i < (int) union_members.elements(); i++) { Explain_select *sel= query->get_select(union_members.at(i)); sel->print_explain(query, output, explain_flags, is_analyze); } if (!using_tmp) return 0; /* Print a line with "UNIT RESULT" */ List item_list; Item *item_null= new (mem_root) Item_null(thd); /* `id` column */ item_list.push_back(item_null, mem_root); /* `select_type` column */ push_str(thd, &item_list, fake_select_type); /* `table` column: something like "" */ uint len= make_union_table_name(table_name_buffer); item_list.push_back(new (mem_root) Item_string_sys(thd, table_name_buffer, len), mem_root); /* `partitions` column */ if (explain_flags & DESCRIBE_PARTITIONS) item_list.push_back(item_null, mem_root); /* `type` column */ push_str(thd, &item_list, join_type_str[JT_ALL]); /* `possible_keys` column */ item_list.push_back(item_null, mem_root); /* `key` */ item_list.push_back(item_null, mem_root); /* `key_len` */ item_list.push_back(item_null, mem_root); /* `ref` */ item_list.push_back(item_null, mem_root); /* `rows` */ item_list.push_back(item_null, mem_root); /* `r_rows` */ StringBuffer<64> r_rows_str; if (is_analyze) { double avg_rows= fake_select_lex_tracker.get_avg_rows(); Item_float *fl= new (mem_root) Item_float(thd, avg_rows, 2); String tmp; String *res= fl->val_str(&tmp); r_rows_str.append(res->ptr()); item_list.push_back(new (mem_root) Item_string_sys(thd, r_rows_str.ptr(), r_rows_str.length()), mem_root); } /* `filtered` */ if (explain_flags & DESCRIBE_EXTENDED || is_analyze) item_list.push_back(item_null, mem_root); /* `r_filtered` */ if (is_analyze) item_list.push_back(item_null, mem_root); /* `Extra` */ StringBuffer<256> extra_buf; if (using_filesort) { extra_buf.append(STRING_WITH_LEN("Using filesort")); } item_list.push_back(new (mem_root) Item_string_sys(thd, extra_buf.ptr(), extra_buf.length()), mem_root); //output->unit.offset_limit_cnt= 0; if (output->send_data(item_list)) return 1; /* Print all subquery children (UNION children have already been printed at the start of this function) */ return print_explain_for_children(query, output, explain_flags, is_analyze); } void Explain_union::print_explain_json(Explain_query *query, Json_writer *writer, bool is_analyze) { Json_writer_nesting_guard guard(writer); char table_name_buffer[SAFE_NAME_LEN]; bool started_object= print_explain_json_cache(writer, is_analyze); writer->add_member("query_block").start_object(); if (is_recursive_cte) writer->add_member("recursive_union").start_object(); else writer->add_member("union_result").start_object(); // using_temporary_table make_union_table_name(table_name_buffer); writer->add_member("table_name").add_str(table_name_buffer); writer->add_member("access_type").add_str("ALL"); // not very useful /* r_loops (not present in tabular output) */ if (is_analyze) { writer->add_member("r_loops").add_ll(fake_select_lex_tracker.get_loops()); } /* `r_rows` */ if (is_analyze) { writer->add_member("r_rows"); if (fake_select_lex_tracker.has_scans()) writer->add_double(fake_select_lex_tracker.get_avg_rows()); else writer->add_null(); } writer->add_member("query_specifications").start_array(); for (int i= 0; i < (int) union_members.elements(); i++) { writer->start_object(); //writer->add_member("dependent").add_str("TODO"); //writer->add_member("cacheable").add_str("TODO"); Explain_select *sel= query->get_select(union_members.at(i)); sel->print_explain_json(query, writer, is_analyze); writer->end_object(); } writer->end_array(); print_explain_json_for_children(query, writer, is_analyze); writer->end_object(); // union_result writer->end_object(); // query_block if (started_object) writer->end_object(); } /* Print EXPLAINs for all children nodes (i.e. for subqueries) */ int Explain_node::print_explain_for_children(Explain_query *query, select_result_sink *output, uint8 explain_flags, bool is_analyze) { for (int i= 0; i < (int) children.elements(); i++) { Explain_node *node= query->get_node(children.at(i)); if (node->print_explain(query, output, explain_flags, is_analyze)) return 1; } return 0; } bool Explain_basic_join::add_table(Explain_table_access *tab, Explain_query *query) { if (!join_tabs) { n_join_tabs= 0; if (!(join_tabs= ((Explain_table_access**) alloc_root(query->mem_root, sizeof(Explain_table_access*) * MAX_TABLES)))) return true; } join_tabs[n_join_tabs++]= tab; return false; } /* This tells whether a child subquery should be printed in JSON output. Derived tables and Non-merged semi-joins should not be printed, because they are printed inline in Explain_table_access. */ bool is_connection_printable_in_json(enum Explain_node::explain_connection_type type) { return (type != Explain_node::EXPLAIN_NODE_DERIVED && type != Explain_node::EXPLAIN_NODE_NON_MERGED_SJ); } void Explain_node::print_explain_json_for_children(Explain_query *query, Json_writer *writer, bool is_analyze) { Json_writer_nesting_guard guard(writer); bool started= false; for (int i= 0; i < (int) children.elements(); i++) { Explain_node *node= query->get_node(children.at(i)); /* Derived tables are printed inside Explain_table_access objects */ if (!is_connection_printable_in_json(node->connection_type)) continue; if (!started) { writer->add_member("subqueries").start_array(); started= true; } writer->start_object(); node->print_explain_json(query, writer, is_analyze); writer->end_object(); } if (started) writer->end_array(); } bool Explain_node::print_explain_json_cache(Json_writer *writer, bool is_analyze) { if (cache_tracker) { cache_tracker->fetch_current_stats(); writer->add_member("expression_cache").start_object(); if (cache_tracker->state != Expression_cache_tracker::OK) { writer->add_member("state"). add_str(Expression_cache_tracker::state_str[cache_tracker->state]); } if (is_analyze) { longlong cache_reads= cache_tracker->hit + cache_tracker->miss; writer->add_member("r_loops").add_ll(cache_reads); if (cache_reads != 0) { double hit_ratio= double(cache_tracker->hit) / cache_reads * 100.0; writer->add_member("r_hit_ratio").add_double(hit_ratio); } } return true; } return false; } Explain_basic_join::~Explain_basic_join() { if (join_tabs) { for (uint i= 0; i< n_join_tabs; i++) delete join_tabs[i]; } } int Explain_select::print_explain(Explain_query *query, select_result_sink *output, uint8 explain_flags, bool is_analyze) { THD *thd= output->thd; MEM_ROOT *mem_root= thd->mem_root; if (select_type == pushed_derived_text || select_type == pushed_select_text) { print_explain_message_line(output, explain_flags, is_analyze, select_id /*select number*/, select_type, NULL, /* rows */ NULL); } else if (message) { List item_list; Item *item_null= new (mem_root) Item_null(thd); item_list.push_back(new (mem_root) Item_int(thd, (int32) select_id), mem_root); item_list.push_back(new (mem_root) Item_string_sys(thd, select_type), mem_root); for (uint i=0 ; i < 7; i++) item_list.push_back(item_null, mem_root); if (explain_flags & DESCRIBE_PARTITIONS) item_list.push_back(item_null, mem_root); /* filtered */ if (is_analyze || explain_flags & DESCRIBE_EXTENDED) item_list.push_back(item_null, mem_root); if (is_analyze) { /* r_rows, r_filtered */ item_list.push_back(item_null, mem_root); item_list.push_back(item_null, mem_root); } item_list.push_back(new (mem_root) Item_string_sys(thd, message), mem_root); if (output->send_data(item_list)) return 1; } else { bool using_tmp= false; bool using_fs= false; for (Explain_aggr_node *node= aggr_tree; node; node= node->child) { switch (node->get_type()) { case AGGR_OP_TEMP_TABLE: using_tmp= true; break; case AGGR_OP_FILESORT: using_fs= true; break; default: break; } } for (uint i=0; i< n_join_tabs; i++) { join_tabs[i]->print_explain(output, explain_flags, is_analyze, select_id, select_type, using_tmp, using_fs); if (i == 0) { /* "Using temporary; Using filesort" should only be shown near the 1st table */ using_tmp= false; 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::add_linkage(Json_writer *writer) { const char *operation= NULL; switch (linkage) { case UNION_TYPE: operation= "UNION"; break; case INTERSECT_TYPE: operation= "INTERSECT"; break; case EXCEPT_TYPE: operation= "EXCEPT"; break; default: // It is the first or the only SELECT => no operation break; } if (operation) writer->add_member("operation").add_str(operation); } void Explain_select::print_explain_json(Explain_query *query, Json_writer *writer, bool is_analyze) { Json_writer_nesting_guard guard(writer); bool started_cache= print_explain_json_cache(writer, is_analyze); if (message || select_type == pushed_derived_text || select_type == pushed_select_text) { writer->add_member("query_block").start_object(); writer->add_member("select_id").add_ll(select_id); add_linkage(writer); writer->add_member("table").start_object(); writer->add_member("message").add_str(select_type == pushed_derived_text ? "Pushed derived" : select_type == pushed_select_text ? "Pushed select" : message); writer->end_object(); print_explain_json_for_children(query, writer, is_analyze); writer->end_object(); } else { writer->add_member("query_block").start_object(); writer->add_member("select_id").add_ll(select_id); add_linkage(writer); if (is_analyze && time_tracker.get_loops()) { writer->add_member("r_loops").add_ll(time_tracker.get_loops()); writer->add_member("r_total_time_ms").add_double(time_tracker.get_time_ms()); } if (exec_const_cond) { writer->add_member("const_condition"); write_item(writer, exec_const_cond); } if (outer_ref_cond) { writer->add_member("outer_ref_condition"); write_item(writer, outer_ref_cond); } if (pseudo_bits_cond) { writer->add_member("pseudo_bits_condition"); write_item(writer, pseudo_bits_cond); } /* we do not print HAVING which always evaluates to TRUE */ if (having || (having_value == Item::COND_FALSE)) { writer->add_member("having_condition"); if (likely(having)) write_item(writer, having); else { /* Normally we should not go this branch, left just for safety */ DBUG_ASSERT(having_value == Item::COND_FALSE); writer->add_str("0"); } } int started_objects= 0; Explain_aggr_node *node= aggr_tree; for (; node; node= node->child) { switch (node->get_type()) { case AGGR_OP_TEMP_TABLE: writer->add_member("temporary_table").start_object(); break; case AGGR_OP_FILESORT: { writer->add_member("filesort").start_object(); ((Explain_aggr_filesort*)node)->print_json_members(writer, is_analyze); break; } case AGGR_OP_REMOVE_DUPLICATES: writer->add_member("duplicate_removal").start_object(); break; case AGGR_OP_WINDOW_FUNCS: { //TODO: make print_json_members virtual? writer->add_member("window_functions_computation").start_object(); ((Explain_aggr_window_funcs*)node)->print_json_members(writer, is_analyze); break; } default: DBUG_ASSERT(0); } started_objects++; } Explain_basic_join::print_explain_json_interns(query, writer, is_analyze); for (;started_objects; started_objects--) writer->end_object(); writer->end_object(); } if (started_cache) writer->end_object(); } Explain_aggr_filesort::Explain_aggr_filesort(MEM_ROOT *mem_root, bool is_analyze, Filesort *filesort) : tracker(is_analyze) { child= NULL; for (ORDER *ord= filesort->order; ord; ord= ord->next) { sort_items.push_back(ord->item[0], mem_root); sort_directions.push_back(&ord->direction, mem_root); } filesort->tracker= &tracker; } void Explain_aggr_filesort::print_json_members(Json_writer *writer, bool is_analyze) { char item_buf[256]; String str(item_buf, sizeof(item_buf), &my_charset_bin); str.length(0); List_iterator_fast it(sort_items); List_iterator_fast it_dir(sort_directions); Item* item; ORDER::enum_order *direction; bool first= true; while ((item= it++)) { direction= it_dir++; if (first) first= false; else { str.append(", "); } append_item_to_str(&str, item); if (*direction == ORDER::ORDER_DESC) str.append(" desc"); } writer->add_member("sort_key").add_str(str.c_ptr_safe()); if (is_analyze) tracker.print_json_members(writer); } void Explain_aggr_window_funcs::print_json_members(Json_writer *writer, bool is_analyze) { Explain_aggr_filesort *srt; List_iterator it(sorts); writer->add_member("sorts").start_object(); while ((srt= it++)) { writer->add_member("filesort").start_object(); srt->print_json_members(writer, is_analyze); writer->end_object(); // filesort } writer->end_object(); // sorts } void Explain_basic_join::print_explain_json(Explain_query *query, Json_writer *writer, bool is_analyze) { writer->add_member("query_block").start_object(); writer->add_member("select_id").add_ll(select_id); print_explain_json_interns(query, writer, is_analyze); writer->end_object(); } void Explain_basic_join:: print_explain_json_interns(Explain_query *query, Json_writer *writer, bool is_analyze) { Json_writer_nesting_guard guard(writer); 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); } void Explain_table_access::push_extra(enum explain_extra_tag extra_tag) { extra_tags.append(extra_tag); } /* Put the contents of 'key' field of EXPLAIN otuput into key_str. It is surprisingly complex: - hash join shows #hash#used_key - quick selects that use single index will print index name */ void Explain_table_access::fill_key_str(String *key_str, bool is_json) const { CHARSET_INFO *cs= system_charset_info; bool is_hj= (type == JT_HASH || type == JT_HASH_NEXT || type == JT_HASH_RANGE || type == JT_HASH_INDEX_MERGE); const char *hash_key_prefix= "#hash#"; if (key.get_key_name()) { if (is_hj) key_str->append(hash_key_prefix, strlen(hash_key_prefix), cs); key_str->append(key.get_key_name()); if (is_hj && type != JT_HASH) key_str->append(':'); } if (quick_info) { StringBuffer<64> buf2; if (is_json) quick_info->print_extra_recursive(&buf2); else quick_info->print_key(&buf2); key_str->append(buf2); } if (type == JT_HASH_NEXT) key_str->append(hash_next_key.get_key_name()); } /* Fill "key_length". - this is just used key length for ref/range - for index_merge, it is a comma-separated list of lengths. - for hash join, it is key_len:pseudo_key_len - [tabular form only] rowid filter length is added after "|". In JSON, we consider this column to be legacy, it is superceded by used_key_parts. */ void Explain_table_access::fill_key_len_str(String *key_len_str, bool is_json) const { bool is_hj= (type == JT_HASH || type == JT_HASH_NEXT || type == JT_HASH_RANGE || type == JT_HASH_INDEX_MERGE); if (key.get_key_len() != (uint)-1) { char buf[64]; size_t length; length= longlong10_to_str(key.get_key_len(), buf, 10) - buf; key_len_str->append(buf, length); if (is_hj && type != JT_HASH) key_len_str->append(':'); } if (quick_info) { StringBuffer<64> buf2; quick_info->print_key_len(&buf2); key_len_str->append(buf2); } if (type == JT_HASH_NEXT) { char buf[64]; size_t length; length= longlong10_to_str(hash_next_key.get_key_len(), buf, 10) - buf; key_len_str->append(buf, length); } if (!is_json && rowid_filter) { key_len_str->append('|'); StringBuffer<64> filter_key_len; rowid_filter->quick->print_key_len(&filter_key_len); key_len_str->append(filter_key_len); } } bool Explain_index_use::set(MEM_ROOT *mem_root, KEY *key, uint key_len_arg) { if (set_pseudo_key(mem_root, key->name.str)) return 1; key_len= key_len_arg; uint len= 0; for (uint i= 0; i < key->usable_key_parts; i++) { if (!key_parts_list.append_str(mem_root, key->key_part[i].field->field_name.str)) return 1; len += key->key_part[i].store_length; if (len >= key_len_arg) break; } return 0; } bool Explain_index_use::set_pseudo_key(MEM_ROOT *root, const char* key_name_arg) { if (key_name_arg) { if (!(key_name= strdup_root(root, key_name_arg))) return 1; } else key_name= NULL; key_len= ~(uint) 0; return 0; } /* Given r_filtered% from join buffer condition and join condition, produce a combined r_filtered% number. This is needed for tabular EXPLAIN output which has only one cell for r_filtered value. */ double Explain_table_access::get_r_filtered() { double r_filtered= tracker.get_filtered_after_where(); if (bka_type.is_using_jbuf()) r_filtered *= jbuf_tracker.get_filtered_after_where(); return r_filtered; } int Explain_table_access::print_explain(select_result_sink *output, uint8 explain_flags, bool is_analyze, uint select_id, const char *select_type, bool using_temporary, bool using_filesort) { THD *thd= output->thd; MEM_ROOT *mem_root= thd->mem_root; List item_list; Item *item_null= new (mem_root) Item_null(thd); /* `id` column */ item_list.push_back(new (mem_root) Item_int(thd, (int32) select_id), mem_root); /* `select_type` column */ push_str(thd, &item_list, select_type); /* `table` column */ push_string(thd, &item_list, &table_name); /* `partitions` column */ if (explain_flags & DESCRIBE_PARTITIONS) { if (used_partitions_set) { push_string(thd, &item_list, &used_partitions); } else item_list.push_back(item_null, mem_root); } /* `type` column */ StringBuffer<64> join_type_buf; if (rowid_filter == NULL) push_str(thd, &item_list, join_type_str[type]); else { join_type_buf.append(join_type_str[type]); join_type_buf.append("|filter"); item_list.push_back(new (mem_root) Item_string_sys(thd, join_type_buf.ptr(), join_type_buf.length()), mem_root); } /* `possible_keys` column */ StringBuffer<64> possible_keys_buf; if (possible_keys.is_empty()) item_list.push_back(item_null, mem_root); else push_string_list(thd, &item_list, possible_keys, &possible_keys_buf); /* `key` */ StringBuffer<64> key_str; fill_key_str(&key_str, false); if (rowid_filter) { key_str.append("|"); StringBuffer<64> rowid_key_str; rowid_filter->quick->print_key(&rowid_key_str); key_str.append(rowid_key_str); } if (key_str.length() > 0) push_string(thd, &item_list, &key_str); else item_list.push_back(item_null, mem_root); /* `key_len` */ StringBuffer<64> key_len_str; fill_key_len_str(&key_len_str, false); if (key_len_str.length() > 0) push_string(thd, &item_list, &key_len_str); else item_list.push_back(item_null, mem_root); /* `ref` */ StringBuffer<64> ref_list_buf; if (ref_list.is_empty()) { if (type == JT_FT) { /* Traditionally, EXPLAIN lines with type=fulltext have ref='' */ push_str(thd, &item_list, ""); } else item_list.push_back(item_null, mem_root); } else push_string_list(thd, &item_list, ref_list, &ref_list_buf); /* `rows` */ StringBuffer<64> rows_str; if (rows_set) { rows_str.append_ulonglong((ulonglong)rows); if (rowid_filter) { rows_str.append(" ("); rows_str.append_ulonglong((ulonglong) (round(rowid_filter->selectivity * 100.0))); rows_str.append("%)"); } item_list.push_back(new (mem_root) Item_string_sys(thd, rows_str.ptr(), rows_str.length()), mem_root); } else item_list.push_back(item_null, mem_root); /* `r_rows` */ StringBuffer<64> r_rows_str; if (is_analyze) { if (!tracker.has_scans()) { item_list.push_back(item_null, mem_root); } else { double avg_rows= tracker.get_avg_rows(); Item_float *fl= new (mem_root) Item_float(thd, avg_rows, 2); String tmp; String *res= fl->val_str(&tmp); r_rows_str.append(res->ptr()); if (rowid_filter) { r_rows_str.append(" ("); r_rows_str.append_ulonglong( (ulonglong) (rowid_filter->tracker->get_r_selectivity_pct() * 100.0)); r_rows_str.append("%)"); } item_list.push_back(new (mem_root) Item_string_sys(thd, r_rows_str.ptr(), r_rows_str.length()), mem_root); } } /* `filtered` */ if (explain_flags & DESCRIBE_EXTENDED || is_analyze) { if (filtered_set) { item_list.push_back(new (mem_root) Item_float(thd, filtered, 2), mem_root); } else item_list.push_back(item_null, mem_root); } /* `r_filtered` */ if (is_analyze) { if (!tracker.has_scans()) { item_list.push_back(item_null, mem_root); } else { double r_filtered= tracker.get_filtered_after_where(); if (bka_type.is_using_jbuf()) r_filtered *= jbuf_tracker.get_filtered_after_where(); item_list.push_back(new (mem_root) Item_float(thd, r_filtered * 100.0, 2), mem_root); } } /* `Extra` */ StringBuffer<256> extra_buf; bool first= true; for (int i=0; i < (int)extra_tags.elements(); i++) { if (first) first= false; else extra_buf.append(STRING_WITH_LEN("; ")); append_tag_name(&extra_buf, extra_tags.at(i)); } if (using_temporary) { if (first) first= false; else extra_buf.append(STRING_WITH_LEN("; ")); extra_buf.append(STRING_WITH_LEN("Using temporary")); } if (using_filesort || this->pre_join_sort) { if (first) first= false; else extra_buf.append(STRING_WITH_LEN("; ")); extra_buf.append(STRING_WITH_LEN("Using filesort")); } if (rowid_filter) { if (first) first= false; else extra_buf.append(STRING_WITH_LEN("; ")); extra_buf.append(STRING_WITH_LEN("Using rowid filter")); } item_list.push_back(new (mem_root) Item_string_sys(thd, extra_buf.ptr(), extra_buf.length()), mem_root); if (output->send_data(item_list)) return 1; return 0; } /** Adds copy of the string to the list @param mem_root where to allocate string @param str string to copy and add @return NULL - out of memory error poiner on allocated copy of the string */ const char *String_list::append_str(MEM_ROOT *mem_root, const char *str) { size_t len= strlen(str); char *cp; if (!(cp = (char*)alloc_root(mem_root, len+1))) return NULL; memcpy(cp, str, len+1); push_back(cp, mem_root); return cp; } static void write_item(Json_writer *writer, Item *item) { THD *thd= current_thd; char item_buf[256]; String str(item_buf, sizeof(item_buf), &my_charset_bin); str.length(0); ulonglong save_option_bits= thd->variables.option_bits; thd->variables.option_bits &= ~OPTION_QUOTE_SHOW_CREATE; item->print(&str, QT_EXPLAIN); thd->variables.option_bits= save_option_bits; writer->add_str(str.c_ptr_safe()); } static void append_item_to_str(String *out, Item *item) { THD *thd= current_thd; ulonglong save_option_bits= thd->variables.option_bits; thd->variables.option_bits &= ~OPTION_QUOTE_SHOW_CREATE; item->print(out, QT_EXPLAIN); thd->variables.option_bits= save_option_bits; } void Explain_table_access::tag_to_json(Json_writer *writer, enum explain_extra_tag tag) { switch (tag) { case ET_OPEN_FULL_TABLE: writer->add_member("open_full_table").add_bool(true); break; case ET_SCANNED_0_DATABASES: writer->add_member("scanned_databases").add_ll(0); break; case ET_SCANNED_1_DATABASE: writer->add_member("scanned_databases").add_ll(1); break; case ET_SCANNED_ALL_DATABASES: writer->add_member("scanned_databases").add_str("all"); break; case ET_SKIP_OPEN_TABLE: writer->add_member("skip_open_table").add_bool(true); break; case ET_OPEN_FRM_ONLY: writer->add_member("open_frm_only").add_bool(true); break; case ET_USING_INDEX_CONDITION: writer->add_member("index_condition"); write_item(writer, pushed_index_cond); break; case ET_USING_INDEX_CONDITION_BKA: writer->add_member("index_condition_bka"); write_item(writer, pushed_index_cond); break; case ET_USING_WHERE: { /* We are printing the condition that is checked when scanning this table. - when join buffer is used, it is cache_cond. - in other cases, it is where_cond. */ Item *item= bka_type.is_using_jbuf()? cache_cond: where_cond; if (item) { writer->add_member("attached_condition"); write_item(writer, item); } } break; case ET_USING_INDEX: writer->add_member("using_index").add_bool(true); break; case ET_USING: // index merge: case ET_USING break; case ET_RANGE_CHECKED_FOR_EACH_RECORD: /* Handled as range_checked_fer */ case ET_USING_JOIN_BUFFER: /* Do nothing. Join buffer is handled differently */ case ET_START_TEMPORARY: case ET_END_TEMPORARY: /* Handled as "duplicates_removal: { ... } */ case ET_FULL_SCAN_ON_NULL_KEY: /* Handled in full_scan_on_null_key */ 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; case ET_USING_MRR: writer->add_member("mrr_type").add_str(mrr_type.c_ptr()); break; case ET_USING_INDEX_FOR_GROUP_BY: writer->add_member("using_index_for_group_by"); if (loose_scan_is_scanning) writer->add_str("scanning"); else writer->add_bool(true); break; /*new:*/ case ET_CONST_ROW_NOT_FOUND: writer->add_member("const_row_not_found").add_bool(true); break; case ET_UNIQUE_ROW_NOT_FOUND: /* Currently, we never get here. All SELECTs that have ET_UNIQUE_ROW_NOT_FOUND for a table are converted into degenerate SELECTs with message="Impossible WHERE ...". MySQL 5.6 has the same property. I'm leaving the handling in just for the sake of covering all enum members and safety. */ writer->add_member("unique_row_not_found").add_bool(true); break; case ET_IMPOSSIBLE_ON_CONDITION: writer->add_member("impossible_on_condition").add_bool(true); break; case ET_USING_WHERE_WITH_PUSHED_CONDITION: /* It would be nice to print the pushed condition, but current Storage Engine API doesn't provide any way to do that */ writer->add_member("pushed_condition").add_bool(true); break; case ET_NOT_EXISTS: writer->add_member("not_exists").add_bool(true); break; case ET_DISTINCT: writer->add_member("distinct").add_bool(true); break; default: DBUG_ASSERT(0); } } static void add_json_keyset(Json_writer *writer, const char *elem_name, String_list *keyset) { if (!keyset->is_empty()) print_json_array(writer, elem_name, *keyset); } void Explain_rowid_filter::print_explain_json(Explain_query *query, Json_writer *writer, bool is_analyze) { Json_writer_nesting_guard guard(writer); writer->add_member("rowid_filter").start_object(); quick->print_json(writer); writer->add_member("rows").add_ll(rows); writer->add_member("selectivity_pct").add_double(selectivity * 100.0); if (is_analyze) { writer->add_member("r_rows").add_double(tracker->get_container_elements()); writer->add_member("r_selectivity_pct"). add_double(tracker->get_r_selectivity_pct() * 100.0); writer->add_member("r_buffer_size"). add_double((double) (tracker->get_container_buff_size())); writer->add_member("r_filling_time_ms"). add_double(tracker->get_time_fill_container_ms()); } writer->end_object(); // rowid_filter } void Explain_table_access::print_explain_json(Explain_query *query, Json_writer *writer, bool is_analyze) { Json_writer_nesting_guard guard(writer); if (pre_join_sort) { /* filesort was invoked on this join tab before doing the join with the rest */ writer->add_member("read_sorted_file").start_object(); if (is_analyze) { writer->add_member("r_rows"); /* r_rows when reading filesort result. This can be less than the number of rows produced by filesort due to NL-join having LIMIT. */ if (tracker.has_scans()) writer->add_double(tracker.get_avg_rows()); else writer->add_null(); /* r_filtered when reading filesort result. We should have checked the WHERE while doing filesort but lets check just in case. */ if (tracker.has_scans() && tracker.get_filtered_after_where() < 1.0) { writer->add_member("r_filtered"); writer->add_double(tracker.get_filtered_after_where()*100.0); } } writer->add_member("filesort").start_object(); pre_join_sort->print_json_members(writer, is_analyze); } if (bka_type.is_using_jbuf()) { writer->add_member("block-nl-join").start_object(); } if (range_checked_fer) { range_checked_fer->print_json(writer, is_analyze); } if (full_scan_on_null_key) writer->add_member("full-scan-on-null_key").start_object(); writer->add_member("table").start_object(); writer->add_member("table_name").add_str(table_name); if (used_partitions_set) print_json_array(writer, "partitions", used_partitions_list); writer->add_member("access_type").add_str(join_type_str[type]); add_json_keyset(writer, "possible_keys", &possible_keys); /* `key` */ /* For non-basic quick select, 'key' will not be present */ if (!quick_info || quick_info->is_basic()) { StringBuffer<64> key_str; fill_key_str(&key_str, true); if (key_str.length()) writer->add_member("key").add_str(key_str); } /* `key_length` */ StringBuffer<64> key_len_str; fill_key_len_str(&key_len_str, true); if (key_len_str.length()) writer->add_member("key_length").add_str(key_len_str); /* `used_key_parts` */ String_list *parts_list= NULL; if (quick_info && quick_info->is_basic()) parts_list= &quick_info->range.key_parts_list; else parts_list= &key.key_parts_list; if (parts_list && !parts_list->is_empty()) print_json_array(writer, "used_key_parts", *parts_list); if (quick_info && !quick_info->is_basic()) { writer->add_member("index_merge").start_object(); quick_info->print_json(writer); writer->end_object(); } /* `ref` */ if (!ref_list.is_empty()) print_json_array(writer, "ref", ref_list); if (rowid_filter) { rowid_filter->print_explain_json(query, writer, is_analyze); } /* r_loops (not present in tabular output) */ if (is_analyze) { writer->add_member("r_loops").add_ll(tracker.get_loops()); } /* `rows` */ if (rows_set) writer->add_member("rows").add_ull(rows); /* `r_rows` */ if (is_analyze) { writer->add_member("r_rows"); if (pre_join_sort) { /* Get r_rows value from filesort */ if (pre_join_sort->tracker.get_r_loops()) writer->add_double(pre_join_sort->tracker.get_avg_examined_rows()); else writer->add_null(); } else { if (tracker.has_scans()) writer->add_double(tracker.get_avg_rows()); else writer->add_null(); } if (op_tracker.get_loops()) { double total_time= op_tracker.get_time_ms(); if (rowid_filter) total_time+= rowid_filter->tracker->get_time_fill_container_ms(); writer->add_member("r_table_time_ms").add_double(total_time); writer->add_member("r_other_time_ms").add_double(extra_time_tracker.get_time_ms()); } } /* `filtered` */ if (filtered_set) writer->add_member("filtered").add_double(filtered); /* `r_filtered` */ if (is_analyze) { writer->add_member("r_filtered"); if (pre_join_sort) { /* Get r_filtered value from filesort */ if (pre_join_sort->tracker.get_r_loops()) writer->add_double(pre_join_sort->tracker.get_r_filtered()*100); else writer->add_null(); } else { /* Get r_filtered from the NL-join runtime */ if (tracker.has_scans()) writer->add_double(tracker.get_filtered_after_where()*100.0); else writer->add_null(); } } for (int i=0; i < (int)extra_tags.elements(); i++) { tag_to_json(writer, extra_tags.at(i)); } if (full_scan_on_null_key) writer->end_object(); //"full-scan-on-null_key" if (range_checked_fer) writer->end_object(); // "range-checked-for-each-record" if (bka_type.is_using_jbuf()) { writer->end_object(); // "block-nl-join" writer->add_member("buffer_type").add_str(bka_type.incremental? "incremental":"flat"); writer->add_member("buffer_size").add_size(bka_type.join_buffer_size); writer->add_member("join_type").add_str(bka_type.join_alg); if (bka_type.mrr_type.length()) writer->add_member("mrr_type").add_str(bka_type.mrr_type); if (where_cond) { writer->add_member("attached_condition"); write_item(writer, where_cond); } if (is_analyze) { //writer->add_member("r_loops").add_ll(jbuf_tracker.get_loops()); writer->add_member("r_filtered"); if (jbuf_tracker.has_scans()) writer->add_double(jbuf_tracker.get_filtered_after_where()*100.0); else writer->add_null(); } } if (derived_select_number) { /* This is a derived table. Print its contents here */ writer->add_member("materialized").start_object(); Explain_node *node= query->get_node(derived_select_number); if (node->get_type() == Explain_node::EXPLAIN_SELECT && ((Explain_select*)node)->is_lateral) { writer->add_member("lateral").add_ll(1); } node->print_explain_json(query, writer, is_analyze); writer->end_object(); } if (non_merged_sjm_number) { /* 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); Explain_node *node= query->get_node(non_merged_sjm_number); node->connection_type= Explain_node::EXPLAIN_NODE_NON_MERGED_SJ; 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(); } if (pre_join_sort) { writer->end_object(); // filesort writer->end_object(); // read_sorted_file } writer->end_object(); } /* Elements in this array match members of enum explain_extra_tag, defined in sql_explain.h */ const char * extra_tag_text[]= { "ET_none", "Using index condition", "Using index condition(BKA)", "Using ", // special handling "Range checked for each record (index map: 0x", // special handling "Using where with pushed condition", "Using where", "Not exists", "Using index", "Full scan on NULL key", "Skip_open_table", "Open_frm_only", "Open_full_table", "Scanned 0 databases", "Scanned 1 database", "Scanned all databases", "Using index for group-by", // special handling "USING MRR: DONT PRINT ME", // special handling "Distinct", "LooseScan", "Start temporary", "End temporary", "FirstMatch", // special handling "Using join buffer", // special handling "Const row not found", "Unique row not found", "Impossible ON condition", }; void Explain_table_access::append_tag_name(String *str, enum explain_extra_tag tag) { switch (tag) { case ET_USING: { // quick select str->append(STRING_WITH_LEN("Using ")); quick_info->print_extra(str); break; } case ET_RANGE_CHECKED_FOR_EACH_RECORD: { /* 4 bits per 1 hex digit + terminating '\0' */ char buf[MAX_KEY / 4 + 1]; str->append(STRING_WITH_LEN("Range checked for each " "record (index map: 0x")); str->append(range_checked_fer->keys_map.print(buf)); str->append(')'); break; } case ET_USING_MRR: { str->append(mrr_type); break; } case ET_USING_JOIN_BUFFER: { str->append(extra_tag_text[tag]); str->append(STRING_WITH_LEN(" (")); const char *buffer_type= bka_type.incremental ? "incremental" : "flat"; str->append(buffer_type); str->append(STRING_WITH_LEN(", ")); str->append(bka_type.join_alg); str->append(STRING_WITH_LEN(" join")); str->append(STRING_WITH_LEN(")")); if (bka_type.mrr_type.length()) { str->append(STRING_WITH_LEN("; ")); str->append(bka_type.mrr_type); } break; } case ET_FIRST_MATCH: { if (firstmatch_table_name.length()) { str->append("FirstMatch("); str->append(firstmatch_table_name); str->append(")"); } else str->append(extra_tag_text[tag]); break; } case ET_USING_INDEX_FOR_GROUP_BY: { str->append(extra_tag_text[tag]); if (loose_scan_is_scanning) str->append(" (scanning)"); break; } default: str->append(extra_tag_text[tag]); } } /* This is called for top-level Explain_quick_select only. The point of this function is: - index_merge should print $index_merge_type (child, ...) - 'range' should not print anything. */ void Explain_quick_select::print_extra(String *str) { if (quick_type == QUICK_SELECT_I::QS_TYPE_RANGE || quick_type == QUICK_SELECT_I::QS_TYPE_RANGE_DESC || quick_type == QUICK_SELECT_I::QS_TYPE_GROUP_MIN_MAX) { /* print nothing */ } else print_extra_recursive(str); } void Explain_quick_select::print_json(Json_writer *writer) { if (is_basic()) { writer->add_member("range").start_object(); writer->add_member("key").add_str(range.get_key_name()); print_json_array(writer, "used_key_parts", range.key_parts_list); writer->end_object(); } else { writer->add_member(get_name_by_type()).start_object(); List_iterator_fast it (children); Explain_quick_select* child; while ((child = it++)) child->print_json(writer); writer->end_object(); } } void Explain_quick_select::print_extra_recursive(String *str) { if (is_basic()) { str->append(range.get_key_name()); } else { str->append(get_name_by_type()); str->append('('); List_iterator_fast it (children); Explain_quick_select* child; bool first= true; while ((child = it++)) { if (first) first= false; else str->append(','); child->print_extra_recursive(str); } str->append(')'); } } const char * Explain_quick_select::get_name_by_type() { switch (quick_type) { case QUICK_SELECT_I::QS_TYPE_INDEX_MERGE: return "sort_union"; case QUICK_SELECT_I::QS_TYPE_ROR_UNION: return "union"; case QUICK_SELECT_I::QS_TYPE_ROR_INTERSECT: return "intersect"; case QUICK_SELECT_I::QS_TYPE_INDEX_INTERSECT: return "sort_intersect"; default: DBUG_ASSERT(0); return "unknown quick select type"; } } /* This prints a comma-separated list of used indexes, ignoring nesting */ void Explain_quick_select::print_key(String *str) { if (quick_type == QUICK_SELECT_I::QS_TYPE_RANGE || quick_type == QUICK_SELECT_I::QS_TYPE_RANGE_DESC || quick_type == QUICK_SELECT_I::QS_TYPE_GROUP_MIN_MAX) { if (str->length() > 0) str->append(','); str->append(range.get_key_name()); } else { List_iterator_fast it (children); Explain_quick_select* child; while ((child = it++)) { child->print_key(str); } } } /* This prints a comma-separated list of used key_lengths, ignoring nesting */ void Explain_quick_select::print_key_len(String *str) { if (quick_type == QUICK_SELECT_I::QS_TYPE_RANGE || quick_type == QUICK_SELECT_I::QS_TYPE_RANGE_DESC || quick_type == QUICK_SELECT_I::QS_TYPE_GROUP_MIN_MAX) { char buf[64]; size_t length; length= longlong10_to_str(range.get_key_len(), buf, 10) - buf; if (str->length() > 0) str->append(','); str->append(buf, length); } else { List_iterator_fast it (children); Explain_quick_select* child; while ((child = it++)) { child->print_key_len(str); } } } int Explain_delete::print_explain(Explain_query *query, select_result_sink *output, uint8 explain_flags, bool is_analyze) { if (deleting_all_rows) { const char *msg= STR_DELETING_ALL_ROWS; int res= print_explain_message_line(output, explain_flags, is_analyze, 1 /*select number*/, select_type, &rows, msg); return res; } else { return Explain_update::print_explain(query, output, explain_flags, is_analyze); } } void Explain_delete::print_explain_json(Explain_query *query, Json_writer *writer, bool is_analyze) { Json_writer_nesting_guard guard(writer); if (deleting_all_rows) { writer->add_member("query_block").start_object(); writer->add_member("select_id").add_ll(1); writer->add_member("table").start_object(); // just like mysql-5.6, we don't print table name. Is this ok? writer->add_member("message").add_str(STR_DELETING_ALL_ROWS); writer->end_object(); // table writer->end_object(); // query_block return; } Explain_update::print_explain_json(query, writer, is_analyze); } int Explain_update::print_explain(Explain_query *query, select_result_sink *output, uint8 explain_flags, bool is_analyze) { StringBuffer<64> key_buf; StringBuffer<64> key_len_buf; StringBuffer<64> extra_str; if (impossible_where || no_partitions) { const char *msg= impossible_where ? STR_IMPOSSIBLE_WHERE : STR_NO_ROWS_AFTER_PRUNING; int res= print_explain_message_line(output, explain_flags, is_analyze, 1 /*select number*/, select_type, NULL, /* rows */ msg); return res; } if (quick_info) { quick_info->print_key(&key_buf); quick_info->print_key_len(&key_len_buf); StringBuffer<64> quick_buf; quick_info->print_extra(&quick_buf); if (quick_buf.length()) { extra_str.append(STRING_WITH_LEN("Using ")); extra_str.append(quick_buf); } } else if (key.get_key_name()) { const char *name= key.get_key_name(); key_buf.set(name, strlen(name), &my_charset_bin); char buf[64]; size_t length= longlong10_to_str(key.get_key_len(), buf, 10) - buf; key_len_buf.copy(buf, length, &my_charset_bin); } if (using_where) { if (extra_str.length() !=0) extra_str.append(STRING_WITH_LEN("; ")); extra_str.append(STRING_WITH_LEN("Using where")); } if (mrr_type.length() != 0) { if (extra_str.length() !=0) extra_str.append(STRING_WITH_LEN("; ")); extra_str.append(mrr_type); } if (is_using_filesort()) { if (extra_str.length() !=0) extra_str.append(STRING_WITH_LEN("; ")); extra_str.append(STRING_WITH_LEN("Using filesort")); } if (using_io_buffer) { if (extra_str.length() !=0) extra_str.append(STRING_WITH_LEN("; ")); extra_str.append(STRING_WITH_LEN("Using buffer")); } /* Single-table DELETE commands do not do "Using temporary". "Using index condition" is also not possible (which is an unjustified limitation) */ double r_filtered= 100 * tracker.get_filtered_after_where(); double r_rows= tracker.get_avg_rows(); print_explain_row(output, explain_flags, is_analyze, 1, /* id */ select_type, table_name.c_ptr(), used_partitions_set? used_partitions.c_ptr() : NULL, jtype, &possible_keys, key_buf.length()? key_buf.c_ptr() : NULL, key_len_buf.length() ? key_len_buf.c_ptr() : NULL, NULL, /* 'ref' is always NULL in single-table EXPLAIN DELETE */ &rows, tracker.has_scans()? &r_rows : NULL, r_filtered, extra_str.c_ptr_safe()); return print_explain_for_children(query, output, explain_flags, is_analyze); } void Explain_update::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(1); /* This is the total time it took to do the UPDATE/DELETE */ if (is_analyze && command_tracker.get_loops()) { writer->add_member("r_total_time_ms"). add_double(command_tracker.get_time_ms()); } if (impossible_where || no_partitions) { const char *msg= impossible_where ? STR_IMPOSSIBLE_WHERE : STR_NO_ROWS_AFTER_PRUNING; writer->add_member("table").start_object(); writer->add_member("message").add_str(msg); writer->end_object(); // table writer->end_object(); // query_block return; } DBUG_ASSERT(!(is_using_filesort() && using_io_buffer)); bool doing_buffering= false; if (is_using_filesort()) { writer->add_member("filesort").start_object(); if (is_analyze) filesort_tracker->print_json_members(writer); doing_buffering= true; } if (using_io_buffer) { writer->add_member("buffer").start_object(); doing_buffering= true; } /* Produce elements that are common for buffered and un-buffered cases */ writer->add_member("table").start_object(); if (get_type() == EXPLAIN_UPDATE) writer->add_member("update").add_ll(1); else writer->add_member("delete").add_ll(1); writer->add_member("table_name").add_str(table_name); if (used_partitions_set) print_json_array(writer, "partitions", used_partitions_list); writer->add_member("access_type").add_str(join_type_str[jtype]); if (!possible_keys.is_empty()) { List_iterator_fast it(possible_keys); const char *name; writer->add_member("possible_keys").start_array(); while ((name= it++)) writer->add_str(name); writer->end_array(); } /* `key`, `key_length` */ if (quick_info && quick_info->is_basic()) { StringBuffer<64> key_buf; StringBuffer<64> key_len_buf; quick_info->print_extra_recursive(&key_buf); quick_info->print_key_len(&key_len_buf); writer->add_member("key").add_str(key_buf); writer->add_member("key_length").add_str(key_len_buf); } else if (key.get_key_name()) { writer->add_member("key").add_str(key.get_key_name()); writer->add_member("key_length").add_str(key.get_key_len()); } /* `used_key_parts` */ String_list *parts_list= NULL; if (quick_info && quick_info->is_basic()) parts_list= &quick_info->range.key_parts_list; else parts_list= &key.key_parts_list; if (parts_list && !parts_list->is_empty()) { List_iterator_fast it(*parts_list); const char *name; writer->add_member("used_key_parts").start_array(); while ((name= it++)) writer->add_str(name); writer->end_array(); } if (quick_info && !quick_info->is_basic()) { writer->add_member("index_merge").start_object(); quick_info->print_json(writer); writer->end_object(); } /* `rows` */ writer->add_member("rows").add_ull(rows); if (mrr_type.length() != 0) writer->add_member("mrr_type").add_str(mrr_type.ptr()); if (is_analyze) { if (doing_buffering) { ha_rows r_rows; double r_filtered; if (is_using_filesort()) { if (filesort_tracker->get_r_loops()) r_rows= (ha_rows) filesort_tracker->get_avg_examined_rows(); else r_rows= 0; r_filtered= filesort_tracker->get_r_filtered() * 100.0; } else { if (buf_tracker.has_scans()) r_rows= (ha_rows) buf_tracker.get_avg_rows(); else r_rows= 0; r_filtered= buf_tracker.get_filtered_after_where() * 100.0; } writer->add_member("r_rows").add_ull(r_rows); writer->add_member("r_filtered").add_double(r_filtered); } else /* Not doing buffering */ { writer->add_member("r_rows"); if (tracker.has_scans()) writer->add_double(tracker.get_avg_rows()); else writer->add_null(); /* There is no 'filtered' estimate in UPDATE/DELETE atm */ double r_filtered= tracker.get_filtered_after_where() * 100.0; writer->add_member("r_filtered").add_double(r_filtered); } if (table_tracker.get_loops()) { writer->add_member("r_total_time_ms"). add_double(table_tracker.get_time_ms()); } } if (where_cond) { writer->add_member("attached_condition"); write_item(writer, where_cond); } /*** The part of plan that is before the buffering/sorting ends here ***/ if (is_using_filesort()) writer->end_object(); if (using_io_buffer) writer->end_object(); writer->end_object(); // table print_explain_json_for_children(query, writer, is_analyze); writer->end_object(); // query_block } int Explain_insert::print_explain(Explain_query *query, select_result_sink *output, uint8 explain_flags, bool is_analyze) { const char *select_type="INSERT"; print_explain_row(output, explain_flags, is_analyze, 1, /* id */ select_type, table_name.c_ptr(), NULL, // partitions JT_ALL, NULL, // possible_keys NULL, // key NULL, // key_len NULL, // ref NULL, // rows NULL, // r_rows 100.0, // r_filtered NULL); return print_explain_for_children(query, output, explain_flags, is_analyze); } void Explain_insert::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(1); writer->add_member("table").start_object(); writer->add_member("table_name").add_str(table_name.c_ptr()); writer->end_object(); // table print_explain_json_for_children(query, writer, is_analyze); writer->end_object(); // query_block } void delete_explain_query(LEX *lex) { DBUG_ENTER("delete_explain_query"); delete lex->explain; lex->explain= NULL; DBUG_VOID_RETURN; } void create_explain_query(LEX *lex, MEM_ROOT *mem_root) { DBUG_ASSERT(!lex->explain); DBUG_ENTER("create_explain_query"); lex->explain= new (mem_root) Explain_query(lex->thd, mem_root); DBUG_ASSERT(mem_root == current_thd->mem_root); DBUG_VOID_RETURN; } void create_explain_query_if_not_exists(LEX *lex, MEM_ROOT *mem_root) { if (!lex->explain) create_explain_query(lex, mem_root); } /** Build arrays for collectiong keys statistics, sdd possible key names to the list and name array @param alloc MEM_ROOT to put data in @param list list of possible key names to fill @param table table of the keys @patam possible_keys possible keys map @retval 0 - OK @retval 1 - Error */ int Explain_range_checked_fer::append_possible_keys_stat(MEM_ROOT *alloc, TABLE *table, key_map possible_keys) { uint j; multi_alloc_root(alloc, &keys_stat, sizeof(ha_rows) * table->s->keys, &keys_stat_names, sizeof(char *) * table->s->keys, NULL); if ((!keys_stat) || (!keys_stat_names)) { keys_stat= NULL; keys_stat_names= NULL; return 1; } keys_map= possible_keys; keys= table->s->keys; bzero(keys_stat, sizeof(ha_rows) * table->s->keys); for (j= 0; j < table->s->keys; j++) { if (possible_keys.is_set(j)) { if (!(keys_stat_names[j]= key_set.append_str(alloc, table->key_info[j].name.str))) return 1; } else keys_stat_names[j]= NULL; } return 0; } void Explain_range_checked_fer::collect_data(QUICK_SELECT_I *quick) { if (quick) { if (quick->index == MAX_KEY) index_merge++; else { DBUG_ASSERT(quick->index < keys); DBUG_ASSERT(keys_stat); DBUG_ASSERT(keys_stat_names); DBUG_ASSERT(keys_stat_names[ quick->index]); keys_stat[quick->index]++; } } else full_scan++; } void Explain_range_checked_fer::print_json(Json_writer *writer, bool is_analyze) { writer->add_member("range-checked-for-each-record").start_object(); add_json_keyset(writer, "keys", &key_set); if (is_analyze) { writer->add_member("r_keys").start_object(); writer->add_member("full_scan").add_ll(full_scan); writer->add_member("index_merge").add_ll(index_merge); if (keys_stat) { writer->add_member("range").start_object(); for (uint i= 0; i < keys; i++) { if (keys_stat_names[i]) { writer->add_member(keys_stat_names[i]).add_ll(keys_stat[i]); } } writer->end_object(); } writer->end_object(); } }