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

…book#626) (facebook#626)

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 (facebook@3b2cc9f)

Pulled By: yoshinorim

fbshipit-source-id: 9f0aee0da20

mysql-test/include/index_merge2.inc

@@ -148,22 +148,28 @@ analyze table t2;
 -- enable_result_log
 -- enable_query_log
 
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 if ($index_merge_random_rows_in_EXPLAIN)
 {
   --replace_column 10 #
 }
 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 (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 if ($index_merge_random_rows_in_EXPLAIN)
 {
   --replace_column 10 #
 }
 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;
@@ -378,12 +384,15 @@ analyze table t1;
 -- enable_result_log
 -- enable_query_log
 
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 if ($index_merge_random_rows_in_EXPLAIN)
 {
   --replace_column 10 #
 }
 # to test the bug, the following must use "sort_union":
 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_2sweeps.inc

@@ -51,7 +51,6 @@ select * from t1 where
   (pk < 5) or (pk > 10 and pk < 15) or (pk >= 50 and pk < 55 ) or (pk > @maxv-10)
   or key1=18 or key1=60;
 
---sorted_result
 select * from t1 where
   (pk < 5) or (pk > 10 and pk < 15) or (pk >= 50 and pk < 55 ) or (pk > @maxv-10)
   or key1 < 3 or key1 > @maxv-11;

mysql-test/include/index_merge_ror.inc

@@ -128,11 +128,16 @@ analyze table t1;
 --echo # One row results tests for cases where a single row matches all conditions
 explain select key1,key2 from t1 where key1=100 and key2=100;
 select key1,key2 from t1 where key1=100 and key2=100;
-explain select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
-# Mask cost values since it varies between runs how much of the indexes
-# are cached in InnoDB's buffer pool
---replace_regex /(_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;
+
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
+  explain select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
+  # Mask cost values since it varies between runs how much of the indexes
+  # are cached in InnoDB's buffer pool
+  --replace_regex /(_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
@@ -146,26 +151,44 @@ analyze table t1;
 -- enable_query_log
 
 --echo #  ROR-intersection, not covering
-explain select key1,key2,filler1 from t1 where key1=100 and key2=100;
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
+  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
-explain select key1,key2 from t1 where key1=100 and key2=100;
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
+  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 (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 explain select key1,key2,key3,key4 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
+}
 select key1,key2,key3,key4 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
-explain select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
+  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
-explain select key1,key2,key3 from t1 where key1=100 and key2=100 and key3=100;
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
+  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');
-explain select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=101;
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
+  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
@@ -182,7 +205,10 @@ 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
-explain select key1,key2,key3,key4,filler1 from t1 where key1=100 and key2=100 or key3=100 and key4=100;
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
+  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;
@@ -196,12 +222,18 @@ 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
---replace_result key2,key1 key1,key2 key4,key3 key3,key4
-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;
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
+  --replace_result key2,key1 key1,key2 key4,key3 key3,key4
+  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
-explain select key1,key2 from t1 where key1=100 and key2=100;
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
+  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.
@@ -216,7 +248,10 @@ analyze table t1;
 -- enable_result_log
 -- enable_query_log
 
-explain select key1,key2,key3,key4,filler1 from t1 where key3=200 or (key1=100 and key2=100) or key4=200;
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
+  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');
@@ -227,7 +262,10 @@ analyze table t1;
 -- enable_result_log
 -- enable_query_log
 
-explain select key1,key2,key3,key4,filler1 from t1 where key3=200 or (key1=100 and key2=100) or key4=200;
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
+  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');
@@ -238,7 +276,10 @@ analyze table t1;
 -- enable_result_log
 -- enable_query_log
 
-explain select key1,key2,key3,key4,filler1 from t1 where key3=200 or (key1=100 and key2=100) or key4=200;
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
+  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 ##
@@ -257,11 +298,20 @@ if (!$index_merge_random_rows_in_EXPLAIN)
 --echo # Do many tests
 --echo # Check that keys that don't improve selectivity are skipped.
 #
-
+if (!$skip_ror_EXPLAIN_for_MyRocks)
+{
 # Different value on 32 and 64 bit
+if ($random_rows_in_EXPLAIN)
+{
+  --replace_column 9 #
+}
 --replace_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 #
+}
 explain select * from t1 where st_b=1 and swt1b=1 and swt2b=1;
 
 if ($index_merge_random_rows_in_EXPLAIN)
@@ -318,6 +368,7 @@ if ($index_merge_random_rows_in_EXPLAIN)
 }
 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;
 

mysql-test/suite/rocksdb/r/index_merge_rocksdb.result

@@ -23,3 +23,26 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index_merge	key1,key2	key1,key2	5,5	NULL	#	Using intersect(key1,key2); Using where
 UPDATE t1 SET filler1='to be deleted' WHERE key1=100 and key2=100;
 DROP TABLE t0, t1;
+create table t1 (key1 int, key2 int, key3 int, key (key1), key (key2), key(key3)) engine=rocksdb;
+insert into t1 values (1, 100, 100), (1, 200, 200), (1, 300, 300);
+analyze table t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	OK
+set global rocksdb_force_flush_memtable_now=1;
+explain select * from t1 where key1 = 1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ref	key1	key1	5	const	#	NULL
+explain select key1,key2 from t1 where key1 = 1 or key2 = 1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index_merge	key1,key2	key1,key2	5,5	NULL	#	Using union(key1,key2); Using where
+select * from t1 where key1 = 1;
+key1	key2	key3
+1	100	100
+1	200	200
+1	300	300
+select key1,key2 from t1 where key1 = 1 or key2 = 1;
+key1	key2
+1	100
+1	200
+1	300
+drop table t1;