From a6a906d76697d5487418d51b251a3070ac6e8c80 Mon Sep 17 00:00:00 2001 From: Oleksandr Byelkin Date: Fri, 25 Nov 2022 12:54:24 +0100 Subject: [PATCH] MDEV-26831 fallout: fix problems of name resolution cache - Avoid passing real field cache as a parameter when we check for duplicates. - Correct cache cleanup (cached field number also have to be reset). - Name resolution cache simple test added. --- .../main/name_resolution_cache_debug.result | 25 +++++++++++++ .../main/name_resolution_cache_debug.test | 36 +++++++++++++++++++ sql/sql_base.cc | 30 +++++++++++++--- 3 files changed, 87 insertions(+), 4 deletions(-) create mode 100644 mysql-test/main/name_resolution_cache_debug.result create mode 100644 mysql-test/main/name_resolution_cache_debug.test diff --git a/mysql-test/main/name_resolution_cache_debug.result b/mysql-test/main/name_resolution_cache_debug.result new file mode 100644 index 00000000000..7030176c5fe --- /dev/null +++ b/mysql-test/main/name_resolution_cache_debug.result @@ -0,0 +1,25 @@ +connect con1,localhost,root; +create table t1 (a int, b int); +create table t2 (c int, d int); +create view v1 as select c+1 as e, d+1 as f from t2; +SET DEBUG_SYNC= 'table_field_cached SIGNAL in_sync WAIT_FOR go'; +prepare stmt1 from "select a from t1"; +execute stmt1; +connection default; +SET DEBUG_SYNC= 'now WAIT_FOR in_sync'; +SET DEBUG_SYNC= 'now SIGNAL go'; +connection con1; +a +SET DEBUG_SYNC= 'table_field_cached SIGNAL in_sync WAIT_FOR go'; +prepare stmt1 from "select e from v1"; +execute stmt1; +connection default; +SET DEBUG_SYNC= 'now WAIT_FOR in_sync'; +SET DEBUG_SYNC= 'now SIGNAL go'; +connection con1; +e +connection default; +disconnect con1; +SET DEBUG_SYNC = 'RESET'; +drop view v1; +drop table t1,t2; diff --git a/mysql-test/main/name_resolution_cache_debug.test b/mysql-test/main/name_resolution_cache_debug.test new file mode 100644 index 00000000000..362d883cbd1 --- /dev/null +++ b/mysql-test/main/name_resolution_cache_debug.test @@ -0,0 +1,36 @@ + +source include/have_debug_sync.inc; + +connect con1,localhost,root; +create table t1 (a int, b int); +create table t2 (c int, d int); +create view v1 as select c+1 as e, d+1 as f from t2; + +SET DEBUG_SYNC= 'table_field_cached SIGNAL in_sync WAIT_FOR go'; +prepare stmt1 from "select a from t1"; +--send execute stmt1 + +connection default; +SET DEBUG_SYNC= 'now WAIT_FOR in_sync'; +SET DEBUG_SYNC= 'now SIGNAL go'; + +connection con1; +--reap + +SET DEBUG_SYNC= 'table_field_cached SIGNAL in_sync WAIT_FOR go'; +prepare stmt1 from "select e from v1"; +--send execute stmt1 + +connection default; +SET DEBUG_SYNC= 'now WAIT_FOR in_sync'; +SET DEBUG_SYNC= 'now SIGNAL go'; + +connection con1; +--reap + +connection default; +disconnect con1; + +SET DEBUG_SYNC = 'RESET'; +drop view v1; +drop table t1,t2; diff --git a/sql/sql_base.cc b/sql/sql_base.cc index d1ee15fb085..dd633f0bb92 100644 --- a/sql/sql_base.cc +++ b/sql/sql_base.cc @@ -6037,7 +6037,10 @@ find_field_in_table(THD *thd, TABLE *table, const char *name, size_t length, if (cached_field_index < table->s->fields && !my_strcasecmp(system_charset_info, table->field[cached_field_index]->field_name.str, name)) + { field= table->field[cached_field_index]; + DEBUG_SYNC(thd, "table_field_cached"); + } else { LEX_CSTRING fname= {name, length}; @@ -6485,6 +6488,13 @@ find_field_in_tables(THD *thd, Item_ident *item, if (last_table) last_table= last_table->next_name_resolution_table; + uint fake_index_for_duplicate_search= NO_CACHED_FIELD_INDEX; + /* + For the field search it will point to field cache, but for duplicate + search it will point to fake_index_for_duplicate_search (no cache + present). + */ + uint *current_cache= &(item->cached_field_index); for (; cur_table != last_table ; cur_table= cur_table->next_name_resolution_table) { @@ -6494,7 +6504,7 @@ find_field_in_tables(THD *thd, Item_ident *item, SQLCOM_SHOW_FIELDS) ? false : check_privileges, allow_rowid, - &(item->cached_field_index), + current_cache, register_tree_change, &actual_table); if (cur_field) @@ -6509,7 +6519,7 @@ find_field_in_tables(THD *thd, Item_ident *item, item->name.str, db, table_name, ref, false, allow_rowid, - &(item->cached_field_index), + current_cache, register_tree_change, &actual_table); if (cur_field) @@ -6526,8 +6536,19 @@ find_field_in_tables(THD *thd, Item_ident *item, Store the original table of the field, which may be different from cur_table in the case of NATURAL/USING join. */ - item->cached_table= (!actual_table->cacheable_table || found) ? - 0 : actual_table; + if (actual_table->cacheable_table /*(1)*/ && !found /*(2)*/) + { + /* + We have just found a field allowed to cache (1) and + it is not dublicate search (2). + */ + item->cached_table= actual_table; + } + else + { + item->cached_table= NULL; + item->cached_field_index= NO_CACHED_FIELD_INDEX; + } DBUG_ASSERT(thd->where); /* @@ -6546,6 +6567,7 @@ find_field_in_tables(THD *thd, Item_ident *item, return (Field*) 0; } found= cur_field; + current_cache= &fake_index_for_duplicate_search; } }