1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
|
--source include/have_ndb.inc
--echo #
--echo # Showing the "ndb_fetch_table_stats" counter
--echo #
--echo # Since fetching table stats incurs one roundtrip to NDB it should not
--echo # be done more than strictly required, the "ndb_fetch_table_stats"
--echo # counter provides a means to check when table stats are fetched.
CREATE TABLE t1 (a int primary key) ENGINE = NDB;
let $count =
`SELECT VARIABLE_VALUE
FROM performance_schema.session_status
WHERE variable_name = 'NDB_FETCH_TABLE_STATS'`;
INSERT INTO t1 VALUES (1);
SELECT * FROM t1;
let $count =
`SELECT VARIABLE_VALUE-$count
FROM performance_schema.session_status
WHERE variable_name = 'NDB_FETCH_TABLE_STATS'`;
echo Table stats was fetched $count time (expected 1);
--echo # Another query using an open handler instance should not cause
--echo # table stats to be fetched again
SELECT * FROM t1;
let $count =
`SELECT VARIABLE_VALUE-$count
FROM performance_schema.session_status
WHERE variable_name = 'NDB_FETCH_TABLE_STATS'`;
echo Table stats was fetched $count times (expected 0);
--echo # Closing handler, should really not need to fetch
--echo # table stats again, but they seem to be
FLUSH TABLES t1;
let $count =
`SELECT VARIABLE_VALUE-$count
FROM performance_schema.session_status
WHERE variable_name = 'NDB_FETCH_TABLE_STATS'`;
echo Table stats was fetched $count times (oops! expected 0);
--echo # Running query again, should cause
--echo # table stats to be fetched once again
SELECT * FROM t1;
let $count =
`SELECT VARIABLE_VALUE-$count
FROM performance_schema.session_status
WHERE variable_name = 'NDB_FETCH_TABLE_STATS'`;
echo Table stats was fetched $count times (expected 1);
DROP TABLE t1;
|
