Fixing index_merge query returning wrong results (facebook#624) (face…

…book#626) [non-RocksDB part]

Summary:
This diff fixed MyRocks returning missing rows if index
merge query plan was used. When index merge is selected,
table->read_map is cleared at
QUICK_RANGE_SELECT::init_ror_merged_scan(). Then
ha_rocksdb::setup_read_decoders() wrongly decided not to decode
all fields, which made MySQL layer decide that keys did not match.
This diff changes ha_rocksdb::setup_read_decoders() to
always decode if read_map is cleared. A side effect is decoding
all fetched fields on index merge. There is a slight performance
penalty but much better than returning wrong results.

This diff reuses index_merge_ror.inc and index_merge_2sweeps.inc
test cases for MyRocks. Since MyRocks query plan is less stable than
InnoDB, it skips using explain and just verifies data correctness.
Closes facebook#626

Differential Revision: D5088547

Pulled By: yoshinorim

mysql-test/include/index_merge2.inc

@@ -154,16 +154,22 @@ analyze table t2;
 -- enable_result_log
 -- enable_query_log
 
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 --replace_regex $elide_costs
 explain select count(*) from t1 where
   key1a = 2 and key1b is null and  key2a = 2 and key2b is null;
+}
 
 select count(*) from t1 where
   key1a = 2 and key1b is null and key2a = 2 and key2b is null;
 
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 --replace_regex $elide_costs
 explain select count(*) from t1 where
   key1a = 2 and key1b is null and key3a = 2 and key3b is null;
+}
 
 select count(*) from t1 where
   key1a = 2 and key1b is null and key3a = 2 and key3b is null;
@@ -378,9 +384,12 @@ analyze table t1;
 -- enable_result_log
 -- enable_query_log
 
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 # to test the bug, the following must use "sort_union":
 --replace_regex $elide_costs
 explain select * from t1 where (key3 > 30 and key3<35) or (key2 >32 and key2 < 40);
+}
 select * from t1 where (key3 > 30 and key3<35) or (key2 >32 and key2 < 40);
 drop table t1;
 

mysql-test/include/index_merge_ror.inc

@@ -133,6 +133,8 @@ analyze table t1;
 --replace_regex $elide_costs_and_rows
 explain select key1,key2 from t1 where key1=100 and key2=100;
 select key1,key2 from t1 where key1=100 and key2=100;
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 --replace_result key2 key1 key4 key3
 --replace_regex $elide_costs_and_rows
 explain select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
@@ -141,6 +143,8 @@ explain select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 o
 --replace_result key2 key1 key4 key3
 --replace_regex /(_rows": )[0-9.]+/\1"#"/ /(_cost": )[\"]*[0-9.]+[\"]*/\1"#"/
 explain format=json select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
+}
+
 select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
 
 --echo # Several-rows results
@@ -154,38 +158,57 @@ analyze table t1;
 -- enable_query_log
 
 --echo #  ROR-intersection, not covering
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
+
 --replace_result key2 key1
 --replace_regex $elide_costs_and_rows
 explain select key1,key2,filler1 from t1 where key1=100 and key2=100;
+}
 select key1,key2,filler1 from t1 where key1=100 and key2=100;
 
 --echo #  ROR-intersection, covering
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 --replace_result key2 key1
 --replace_regex $elide_costs_and_rows
 explain select key1,key2 from t1 where key1=100 and key2=100;
+}
 select key1,key2 from t1 where key1=100 and key2=100;
 
 --echo #  ROR-union of ROR-intersections
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 --replace_result key2 key1 key4 key3
 --replace_regex $elide_costs_and_rows
 explain select key1,key2,key3,key4 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
+}
 select key1,key2,key3,key4 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 --replace_result key2 key1 key4 key3
 --replace_regex $elide_costs_and_rows
 explain select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
+}
 select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
 
 --echo #  3-way ROR-intersection
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 --replace_result key2 key1 key3 key1
 --replace_regex $elide_costs_and_rows
 explain select key1,key2,key3 from t1 where key1=100 and key2=100 and key3=100;
+}
 select key1,key2,key3 from t1 where key1=100 and key2=100 and key3=100;
 
 --echo #  ROR-union(ROR-intersection, ROR-range)
 insert into t1 (key1,key2,key3,key4,filler1) values (101,101,101,101, 'key1234-101');
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 --replace_result key2 key1
 --replace_regex $elide_costs_and_rows
 explain select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=101;
+}
 select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=101;
 
 --echo # Run some ROR updates/deletes
@@ -202,9 +225,12 @@ select key1,key2,filler1 from t1 where key2=100 and key2=200;
 
 --echo # ROR-union(ROR-intersection) with one of ROR-intersection giving empty
 --echo # results
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 --replace_result key2 key1 key4 key3
 --replace_regex $elide_costs_and_rows
 explain select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
+}
 select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
 
 delete from t1 where key3=100 and key4=100;
@@ -218,15 +244,21 @@ analyze table t1;
 --echo # ROR-union with all ROR-intersections giving empty results
 # The relative order of keys inside 
 # "Using union(intersect(keyx,keyx),...)" doesn't matter
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 --replace_result key2 key1 key4 key3
 --replace_regex $elide_costs_and_rows
 explain select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
 select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
+}
 
 --echo # ROR-intersection with empty result
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 --replace_result key2 key1 key4 key3
 --replace_regex $elide_costs_and_rows
 explain select key1,key2 from t1 where key1=100 and key2=100;
+}
 select key1,key2 from t1 where key1=100 and key2=100;
 
 --echo # ROR-union tests with various cases.
@@ -241,9 +273,12 @@ analyze table t1;
 -- enable_result_log
 -- enable_query_log
 
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 --replace_result key2 key1 key4 key3
 --replace_regex $elide_costs_and_rows
 explain select key1,key2,key3,key4,filler1 from t1 where key3=200 or (key1=100 and key2=100) or key4=200;
+}
 select key1,key2,key3,key4,filler1 from t1 where key3=200 or (key1=100 and key2=100) or key4=200;
 
 insert into t1 (key1, key2, key3, key4, filler1) values (-1, -1, -1, 200,'key4');
@@ -254,9 +289,12 @@ analyze table t1;
 -- enable_result_log
 -- enable_query_log
 
---replace_result key2 key1 key4 key3
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
+ --replace_result key2 key1 key4 key3
 --replace_regex $elide_costs_and_rows
 explain select key1,key2,key3,key4,filler1 from t1 where key3=200 or (key1=100 and key2=100) or key4=200;
+}
 select key1,key2,key3,key4,filler1 from t1 where key3=200 or (key1=100 and key2=100) or key4=200;
 
 insert into t1 (key1, key2, key3, key4, filler1) values (-1, -1, 200, -1,'key3');
@@ -267,9 +305,12 @@ analyze table t1;
 -- enable_result_log
 -- enable_query_log
 
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 --replace_result key2 key1 key4 key3
 --replace_regex $elide_costs_and_rows
 explain select key1,key2,key3,key4,filler1 from t1 where key3=200 or (key1=100 and key2=100) or key4=200;
+}
 select key1,key2,key3,key4,filler1 from t1 where key3=200 or (key1=100 and key2=100) or key4=200;
 
 --echo ##
@@ -288,12 +329,21 @@ if ($engine_type != "InnoDB" )
 --echo # Do many tests
 --echo # Check that keys that don't improve selectivity are skipped.
 #
-
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 # Different value on 32 and 64 bit
+if ($random_rows_in_EXPLAIN)
+{
+  --replace_column 9 #
+}
 --replace_regex $elide_costs_and_rows
 --replace_result sta_swt12a sta_swt21a sta_swt12a, sta_swt12a,
 explain select * from t1 where st_a=1 and swt1a=1 and swt2a=1;
 
+if ($random_rows_in_EXPLAIN)
+{
+  --replace_column 9 #
+}
 --replace_regex $elide_costs_and_rows
 explain select * from t1 where st_b=1 and swt1b=1 and swt2b=1;
 
@@ -327,6 +377,7 @@ explain select st_a from t1
 --replace_regex $elide_costs_and_rows
 explain select st_a from t1
   where st_a=1 and swt1a=1 and st_b=1 and swt1b=1 and swt1b=1;
+}
 
 drop table t0,t1;