diff options
| -rw-r--r-- | mysql-test/main/merge.result | 11 | ||||
| -rw-r--r-- | mysql-test/main/merge.test | 8 | ||||
| -rw-r--r-- | sql/opt_range.cc | 11 |
3 files changed, 30 insertions, 0 deletions
diff --git a/mysql-test/main/merge.result b/mysql-test/main/merge.result index 820372efe85..1eecb3e34ca 100644 --- a/mysql-test/main/merge.result +++ b/mysql-test/main/merge.result @@ -3944,6 +3944,17 @@ CREATE TABLE tm (a INT, KEY(a)) ENGINE=MRG_MyISAM UNION=(t1,t2); SELECT DISTINCT a FROM tm WHERE a > 50; a DROP TABLE tm, t1, t2; +# Testcase 2: +CREATE TABLE t1 (a INT, KEY(a)) ENGINE=MyISAM; +CREATE TABLE t2 (a INT, KEY(a)) ENGINE=MyISAM; +CREATE TABLE tm (a INT, KEY(a)) ENGINE=MERGE UNION = (t1, t2) INSERT_METHOD=FIRST; +ANALYZE TABLE tm PERSISTENT FOR ALL; +Table Op Msg_type Msg_text +test.tm analyze status Engine-independent statistics collected +test.tm analyze note The storage engine for the table doesn't support analyze +SELECT DISTINCT a FROM (SELECT * FROM tm WHERE a iS NOT NULL) AS sq; +a +DROP TABLE tm, t1, t2; # # MDEV-30568 Assertion `cond_selectivity <= 1.000000001' failed in get_range_limit_read_cost # diff --git a/mysql-test/main/merge.test b/mysql-test/main/merge.test index 8da9e7b3a1c..6b88d427fb4 100644 --- a/mysql-test/main/merge.test +++ b/mysql-test/main/merge.test @@ -2905,6 +2905,14 @@ CREATE TABLE tm (a INT, KEY(a)) ENGINE=MRG_MyISAM UNION=(t1,t2); SELECT DISTINCT a FROM tm WHERE a > 50; DROP TABLE tm, t1, t2; +--echo # Testcase 2: +CREATE TABLE t1 (a INT, KEY(a)) ENGINE=MyISAM; +CREATE TABLE t2 (a INT, KEY(a)) ENGINE=MyISAM; +CREATE TABLE tm (a INT, KEY(a)) ENGINE=MERGE UNION = (t1, t2) INSERT_METHOD=FIRST; +ANALYZE TABLE tm PERSISTENT FOR ALL; +SELECT DISTINCT a FROM (SELECT * FROM tm WHERE a iS NOT NULL) AS sq; +DROP TABLE tm, t1, t2; + --echo # --echo # MDEV-30568 Assertion `cond_selectivity <= 1.000000001' failed in get_range_limit_read_cost --echo # diff --git a/sql/opt_range.cc b/sql/opt_range.cc index 0fad2d6e201..611917ab1a6 100644 --- a/sql/opt_range.cc +++ b/sql/opt_range.cc @@ -14527,6 +14527,17 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree, double read_time) if ((cur_index_tree= tree->keys[cur_param_idx])) { cur_quick_prefix_records= param->quick_rows[cur_index]; + if (!cur_quick_prefix_records) + { + /* + Non-constant table has a range with rows=0. Can happen e.g. for + Merge tables. Regular range access will be just as good as loose + scan. + */ + if (unlikely(trace_idx.trace_started())) + trace_idx.add("aborting_search", "range with rows=0"); + DBUG_RETURN(NULL); + } if (unlikely(cur_index_tree && thd->trace_started())) { Json_writer_array trace_range(thd, "ranges"); |