From c5ed7a87f42259ddf853d9a9c16e0596f7aa9983 Mon Sep 17 00:00:00 2001 From: "gkodinov@mysql.com" <> Date: Mon, 19 Jun 2006 13:22:42 +0300 Subject: [PATCH 1/2] * Bug #9676: INSERT INTO x SELECT .. FROM x LIMIT 1; slows down with big tables Currently in INSERT ... SELECT ... LIMIT ... the compiler uses a temporary table to store the results of SELECT ... LIMIT .. and then uses that table as a source for INSERT. The problem is that in some cases it actually skips the LIMIT clause in doing that and materializes the whole SELECT result set regardless of the LIMIT. This fix is limiting the process of filling up the temp table with only that much rows that will be actually used by propagating the LIMIT value. --- mysql-test/r/insert_select.result | 4 ++++ mysql-test/t/insert_select.test | 13 +++++++++++++ sql/sql_select.cc | 12 ++++++++---- 3 files changed, 25 insertions(+), 4 deletions(-) diff --git a/mysql-test/r/insert_select.result b/mysql-test/r/insert_select.result index 028b40ac3b6..1d7aef256e1 100644 --- a/mysql-test/r/insert_select.result +++ b/mysql-test/r/insert_select.result @@ -686,3 +686,7 @@ ERROR 42S22: Unknown column 'z' in 'field list' insert into t1(x,y) select x,z from t2 on duplicate key update x=values(t2.x); ERROR 42S02: Unknown table 't2' in field list drop table t1,t2; +CREATE TABLE t1 (a int PRIMARY KEY); +INSERT INTO t1 values (1), (2); +INSERT INTO t1 SELECT a + 2 FROM t1 LIMIT 1; +DROP TABLE t1; diff --git a/mysql-test/t/insert_select.test b/mysql-test/t/insert_select.test index 48acdf1cbc5..fcea489fcff 100644 --- a/mysql-test/t/insert_select.test +++ b/mysql-test/t/insert_select.test @@ -226,4 +226,17 @@ insert into t1(x,y) select x,z from t2 on duplicate key update x=values(z); insert into t1(x,y) select x,z from t2 on duplicate key update x=values(t2.x); drop table t1,t2; +# +# Bug #9676: INSERT INTO x SELECT .. FROM x LIMIT 1; slows down with big +# tables +# + +#Note: not an exsaustive test : just a check of the code path. +CREATE TABLE t1 (a int PRIMARY KEY); +INSERT INTO t1 values (1), (2); + +INSERT INTO t1 SELECT a + 2 FROM t1 LIMIT 1; + +DROP TABLE t1; + # End of 4.1 tests diff --git a/sql/sql_select.cc b/sql/sql_select.cc index 5a7e9e52aed..709ff9726bb 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -888,8 +888,9 @@ JOIN::optimize() group_list ? 0 : select_distinct, group_list && simple_group, select_options, - (order == 0 || skip_sort_order) ? select_limit : - HA_POS_ERROR, + (order == 0 || skip_sort_order || + test(select_options & OPTION_BUFFER_RESULT)) ? + select_limit : HA_POS_ERROR, (char *) ""))) DBUG_RETURN(1); @@ -5530,6 +5531,11 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List &fields, keyinfo->key_length+= key_part_info->length; } } + else + { + set_if_smaller(table->max_rows, rows_limit); + param->end_write_records= rows_limit; + } if (distinct && field_count != param->hidden_field_count) { @@ -5544,8 +5550,6 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List &fields, null_pack_length-=hidden_null_pack_length; keyinfo->key_parts= ((field_count-param->hidden_field_count)+ test(null_pack_length)); - set_if_smaller(table->max_rows, rows_limit); - param->end_write_records= rows_limit; table->distinct=1; table->keys=1; if (blob_count) From ae6970e6bc4cf01a2c91ddaabf8ec31b4377e04c Mon Sep 17 00:00:00 2001 From: "evgen@moonbone.local" <> Date: Tue, 20 Jun 2006 23:05:55 +0400 Subject: [PATCH 2/2] select.result: Added test case for bug#18759 Incorrect string to numeric conversion. select.test: Added test case for bug#18759 Incorrect string to numeric conversion. item_cmpfunc.cc: Cleanup after fix for bug#18360 removal --- mysql-test/r/select.result | 6 ++++++ mysql-test/t/select.test | 19 +++++++++++++++++++ sql/item_cmpfunc.cc | 3 ++- 3 files changed, 27 insertions(+), 1 deletion(-) diff --git a/mysql-test/r/select.result b/mysql-test/r/select.result index 7808e787e39..c7df11ab018 100644 --- a/mysql-test/r/select.result +++ b/mysql-test/r/select.result @@ -2738,3 +2738,9 @@ ERROR HY000: Key 'a' doesn't exist in table 't1' EXPLAIN SELECT * FROM t1 FORCE INDEX (a); ERROR HY000: Key 'a' doesn't exist in table 't1' DROP TABLE t1; +CREATE TABLE t1 (i BIGINT UNSIGNED NOT NULL); +INSERT INTO t1 VALUES (10); +SELECT i='1e+01',i=1e+01, i in (1e+01), i in ('1e+01') FROM t1; +i='1e+01' i=1e+01 i in (1e+01) i in ('1e+01') +0 1 1 1 +DROP TABLE t1; diff --git a/mysql-test/t/select.test b/mysql-test/t/select.test index f7b5a2fbcb6..4cdfc220350 100644 --- a/mysql-test/t/select.test +++ b/mysql-test/t/select.test @@ -2278,4 +2278,23 @@ EXPLAIN SELECT * FROM t1 FORCE INDEX (a); DROP TABLE t1; +# +# Bug #18759 "Incorrect string to numeric conversion" +# +# This test is here so that the behavior will not be changed to 4.1 +# and not to 5.0 either. In 4.1 and 5.0 sending an integer as a string +# will be converted internally to real (double) value and it is not +# as accurate as bigint (longlong) for integers. Thus the results may +# vary. In 5.1 internally it is decimal, which is a string type and +# will be more accurate. Due to rather big changes needed to fix this +# in 4.1 or 5.0 it is not desired to do it in the stable versions. +# +# This test is here only to make sure that behavior is not changed in +# 4.1 and 5.0 +# +CREATE TABLE t1 (i BIGINT UNSIGNED NOT NULL); +INSERT INTO t1 VALUES (10); +SELECT i='1e+01',i=1e+01, i in (1e+01), i in ('1e+01') FROM t1; +DROP TABLE t1; + # End of 4.1 tests diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc index 5055b5f4197..f14efc7187b 100644 --- a/sql/item_cmpfunc.cc +++ b/sql/item_cmpfunc.cc @@ -136,7 +136,8 @@ static void agg_cmp_type(THD *thd, Item_result *type, Item **items, uint nitems) } continue; } - if ((res= items[i]->real_item()->type()) == Item::FIELD_ITEM) + if ((res= items[i]->real_item()->type()) == Item::FIELD_ITEM && + items[i]->result_type() != INT_RESULT) { field= ((Item_field *)items[i]->real_item())->field; break;