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Commit 7fe7e431 authored by Patrick Crews's avatar Patrick Crews
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parents ae408f63 7b62ee3e
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mysql-test/r/func_misc.result
View file @ 7fe7e431
......@@ -104,76 +104,99 @@ t1 CREATE TABLE `t1` (
`length(uuid())` int(10) NOT NULL DEFAULT '0'
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 (id int,
a timestamp default '2005-05-05 01:01:01',
b timestamp default '2005-05-05 01:01:01');
insert into t1 set id = 1,a = now();
select sleep(3);
sleep(3)
0
update t1 set b = now() where id = 1;
insert into t1 set id = 2,a = now();
select sleep(3);
sleep(3)
0
update t1 set b = now() where id = 2;
select count(*) >= 1 from t1
where timediff(b, a) between '00:00:03' and '00:00:07';
count(*) >= 1
1
drop table t1;
#------------------------------------------------------------------------
# Tests for Bug#6760 and Bug#12689
SET @row_count = 4;
SET @sleep_time_per_result_row = 1;
SET @max_acceptable_delay = 2;
SET @@global.query_cache_size = 1024 * 64;
SELECT 1 as some_value, sleep(1);
some_value sleep(1)
1 0
SELECT <Qcache_queries_in_cache_before> = <Qcache_queries_in_cache_before>
AS "Was the query not cached (= expectation)?";
Was the query not cached (= expectation)?
1
DROP TEMPORARY TABLE IF EXISTS proclist_history;
DROP TABLE IF EXISTS t1;
CREATE TEMPORARY TABLE proclist_history AS
SELECT 'Bug 1' AS test, 0 AS attempt, NOW() AS observation_time, state, time
FROM information_schema.processlist WHERE 1 = 0;
DROP TEMPORARY TABLE IF EXISTS t_history;
DROP TABLE IF EXISTS t1;
CREATE TEMPORARY TABLE t_history (attempt SMALLINT,
start_ts DATETIME, end_ts DATETIME,
start_cached INTEGER, end_cached INTEGER);
CREATE TABLE t1 (f1 BIGINT);
INSERT INTO t1 VALUES (1);
INSERT INTO t1 VALUES (1);
INSERT INTO t1 VALUES (1);
INSERT INTO t1 VALUES (1);
SET @sleep_time_per_result_row = 1;
----- establish connection con1 (user = root) -----
SET @sleep_time_per_result_row = 1;
Qcache_queries_in_cache: 0
# Send query with send, pull server responses later
SELECT sleep(@sleep_time_per_result_row) FROM t1;
----- switch to connection default (user = root) -----
----- switch to connection con1 (user = root) -----
# Pull server responses of last query
sleep(@sleep_time_per_result_row)
0
0
0
0
----- switch to connection con1 (user = root) -----
# Send query with send, pull server responses later
SELECT sleep(@sleep_time_per_result_row) FROM t1;
----- switch to connection default (user = root) -----
SELECT COUNT(*) FROM information_schema.processlist
WHERE info = 'SELECT sleep(@sleep_time_per_result_row) FROM t1'
AND state = 'User sleep';
COUNT(*)
INSERT INTO t_history
SET attempt = 4 - 4 + 1, start_ts = NOW(),
start_cached = 0;
SELECT *, SLEEP(@sleep_time_per_result_row) FROM t1;
f1 SLEEP(@sleep_time_per_result_row)
1 0
1 0
1 0
1 0
UPDATE t_history SET end_ts = NOW()
WHERE attempt = 4 - 4 + 1;
UPDATE t_history SET end_cached = 0
WHERE attempt = 4 - 4 + 1;
INSERT INTO t_history
SET attempt = 4 - 3 + 1, start_ts = NOW(),
start_cached = 0;
SELECT *, SLEEP(@sleep_time_per_result_row) FROM t1;
f1 SLEEP(@sleep_time_per_result_row)
1 0
1 0
1 0
1 0
UPDATE t_history SET end_ts = NOW()
WHERE attempt = 4 - 3 + 1;
UPDATE t_history SET end_cached = 0
WHERE attempt = 4 - 3 + 1;
INSERT INTO t_history
SET attempt = 4 - 2 + 1, start_ts = NOW(),
start_cached = 0;
SELECT *, SLEEP(@sleep_time_per_result_row) FROM t1;
f1 SLEEP(@sleep_time_per_result_row)
1 0
1 0
1 0
1 0
UPDATE t_history SET end_ts = NOW()
WHERE attempt = 4 - 2 + 1;
UPDATE t_history SET end_cached = 0
WHERE attempt = 4 - 2 + 1;
INSERT INTO t_history
SET attempt = 4 - 1 + 1, start_ts = NOW(),
start_cached = 0;
SELECT *, SLEEP(@sleep_time_per_result_row) FROM t1;
f1 SLEEP(@sleep_time_per_result_row)
1 0
1 0
1 0
1 0
UPDATE t_history SET end_ts = NOW()
WHERE attempt = 4 - 1 + 1;
UPDATE t_history SET end_cached = 0
WHERE attempt = 4 - 1 + 1;
# Test 1: Does the query with SLEEP need a reasonable time?
SELECT COUNT(*) > 4 - 1 INTO @aux1 FROM t_history
WHERE TIMEDIFF(end_ts,start_ts) - @sleep_time_per_result_row * @row_count
BETWEEN 0 AND @max_acceptable_delay;
SELECT @aux1 AS "Expect 1";
Expect 1
1
# Test 2: Does the query with SLEEP need a reasonable time even in case
# of the non first execution?
SELECT COUNT(*) > 4 - 1 - 1 INTO @aux2 FROM t_history
WHERE TIMEDIFF(end_ts,start_ts) - @sleep_time_per_result_row * @row_count
BETWEEN 0 AND @max_acceptable_delay
AND attempt > 1;
SELECT @aux2 AS "Expect 1";
Expect 1
1
# Test 3: The query with SLEEP must be not cached.
SELECT COUNT(*) = 4 INTO @aux3 FROM t_history
WHERE end_cached = start_cached;
SELECT @aux3 AS "Expect 1";
Expect 1
1
----- switch to connection con1 (user = root) -----
# Pull server responses of last query
sleep(@sleep_time_per_result_row)
0
0
0
0
----- switch to connection default and close connection con1 -----
SET @@global.query_cache_size = default;
DROP TABLE t1;
DROP TEMPORARY TABLE proclist_history;
DROP TEMPORARY TABLE t_history;
SET @@global.query_cache_size = default;
create table t1 select INET_ATON('255.255.0.1') as `a`;
show create table t1;
Table Create Table
......
mysql-test/t/func_misc.test
View file @ 7fe7e431
......@@ -103,295 +103,192 @@ show create table t1;
drop table t1;
#
# Bug #6760: Add SLEEP() function
# Bug#6760: Add SLEEP() function (feature request)
#
# Note (mleich):
# --------------
# The experiments around
# Logics of original test:
# Reveal that a query with SLEEP does not need less time than estimated.
#
# Bug#12689: SLEEP() gets incorrectly cached/optimized-away
#
# Description from bug report (slightly modified)
#
# Bug 1 (happened all time):
# SELECT * FROM t1 WHERE SLEEP(1) will only result in a sleep of 1
# second, regardless of the number of rows in t1.
# Bug 2 (happened all time):
# Such a query will also get cached by the query cache, but should not.
#
# Notes (mleich, 2008-05)
# =======================
#
# Experiments around
# Bug#36345 Test 'func_misc' fails on RHAS3 x86_64
# showed that the original test for Bug#6760 produced false alarms in case
# of parallel system time decreases. It was therefore modified.
# Solution:
# We run the test two times and assume a pass if at least one attempt
# is successful. The disadvantage is that a parallel "unnatural" increase of
# system time (set time via ntpd etc.) is able to hide a wrong working SLEEP
# function. This is no problem because
# - such changes of the system are rare
# - there is an extreme high probability that either the following test
# or the frequent runs of the current test on the current testing box or
# other boxes catch a wrong working SLEEP function.
create table t1 (id int,
a timestamp default '2005-05-05 01:01:01',
b timestamp default '2005-05-05 01:01:01');
insert into t1 set id = 1,a = now();
select sleep(3);
update t1 set b = now() where id = 1;
insert into t1 set id = 2,a = now();
select sleep(3);
update t1 set b = now() where id = 2;
# Check that the timediff caused by the length of the sleep is not plain wrong.
# We can have delays in statement processing of 1 - 2 seconds on
# an overloaded testing box.
# Minimum (= ideal) real timediff = '00:00:03'
# Maximum acceptable real timediff = '00:00:07'
select count(*) >= 1 from t1
where timediff(b, a) between '00:00:03' and '00:00:07';
drop table t1;
################################################################################
# Bug #12689: SLEEP() gets incorrectly cached/optimized-away
#
# Description from bug report (slightly modified)
# ===============================================
# Bug 1 (happened all time):
# SELECT * FROM t1 WHERE SLEEP(1) will only result in a sleep of 1
# second, regardless of the number of rows in t1.
# Bug 2 (happened all time):
# Such a query will also get cached by the query cache, but should not.
#
# Notes (mleich, May 2008)
# ========================
# 1. The testcase for this bug had to be reimplemented because of
# Bug#36345 Test 'func_misc' fails on RHAS3 x86_64
# - Bad effect: We did not reach the expected time differences.
# - Experiments showed that for example a parallel change of the system
# time (decrease of time value) like via ntpd provokes this effect.
#
# It is a clear error within the setup of the testing environment if
# tests relying on derivates of the system time can meet parallel
# manipulations of this time. Covering these weaknesses by workarounds
# within the tests is often not perfect doable at all and costs
# significant development and/or runtime per test.
#
# Results of experiments with/without manipulation of system time:
# ----------------------------------------------------------------
# Definition: Predicted_cumulative_sleep_time =
# #_of_result_rows * sleep_time_per_result_row
# processlist.time refers to the session in state 'User sleep'
#
# 1. Total (real sleep time) ~= predicted_cumulative_sleep_time !!
# 2. processlist.time behaves "synchronous" to system time and NOW() and
# shows also the "jumps" caused by system time manipulations
# 3. processlist.time is unsigned, the next value below 0 is ~ 4G
# 4. Current processlist.time ~= current real sleep time
# if the system time was not manipulated
#
# 2. How to reveal the absence of Bug 1:
#
# The state of a session within the PROCESSLIST changes to 'User sleep'
# showed that the tests for both bugs could produce in case of parallel
# artificial system time (like via ntpd)
# - decreases false alarm
# - increases false success
#
# We try here to circumvent these issues by reimplementation of the tests
# and sophisticated scripting, although the cause of the problems is a massive
# error within the setup of the testing environment.
# Tests relying on or checking derivates of the system time must never meet
# parallel manipulations of system time.
#
# Results of experiments with/without manipulation of system time,
# information_schema.processlist content, high load on testing box
# ----------------------------------------------------------------
# Definition: Predicted_cumulative_sleep_time =
# #_of_result_rows * sleep_time_per_result_row
#
# 1. Total (real sleep time) ~= predicted_cumulative_sleep_time !!
# 2. The state of a session within the PROCESSLIST changes to 'User sleep'
# if the sessions runs a statement containing the sleep function and the
# processing of the statement is just within the phase where the sleep
# is done.
#
# As soon as the "Real" time where the session is in state 'User sleep'
# exceeds the sleep_time_per_result_row we can be sure that the execution
# of the query slept more time than needed for just one row.
#
# "Real" time in state 'User sleep' > sleep_time_per_result_row
#
# Estimation 1:
# -------------
# n = how often we observed the session is in state 'User sleep'
#
# "Real" time in state 'User sleep'
# = (n - 1) * sleep_time_in_loop
# + time needed for the execution of the statements within the loop
# (includes the time waiting for getting resources like CPU etc.
# which si significant in case of high load on testing box)
#
# (n - 1) * sleep_time_in_loop >= sleep_time_per_result_row
#
# n >= sleep_time_per_result_row / sleep_time_in_loop + 1
#
# Simplification taking truncation of values etc. into account:
# n >= sleep_time_per_result_row / sleep_time_in_loop + 2
#
# We cannot have met Bug 1 if
# n >= sleep_time_per_result_row / sleep_time_in_loop + 2
# is fulfilled.
# But there is a significant risk that a run on an overloaded box
# does not reach the estimated limit.
#
# Estimation 2:
# -------------
# processlist.time should show how long a session is within the current
# state. I verified by experimenting that this value is not reset per
# row of the the result set.
#
# "Real" time in state 'User sleep'
# >= highest observed value of processlist.time
#
# We cannot have met Bug 1 if
# highest observed value of processlist.time > sleep_time_per_result_row
# is fulfilled.
# Unfortunately processlist.time is no more reliable in case of parallel
# changes of the system time.
#
# Final solution:
# ---------------
# Run a subtest with "judging" based on estimation 1. If the limit is not
# reached, assume that we suffered from high load and try estimation 2.
# If estimation 2 gets cheated by parallel increase of system time
# assume that later runs on the same box or other boxes will show if
# Bug#12689 occured again.
#
# 3. How to reveal the absence of Bug 2:
# - By checking the behaviour during second execution:
# We run the same statement again and meet the session at least once in
# state 'User sleep'.
# - By checking secondary information (query cache statistics)
# The first execution of the statment must not cause that
# Qcache_queries_in_cache is incremented.
#
# 4. We do not run
# --source include/have_query_cache.inc
# at the beginning of this script because we want that this script is not
# skipped if the query cache is disabled. This means the detection of wrongly
# cached queries is in such cases without real effect.
#
# 5. Thanks to Davi for excellent hints and ideas.
#
################################################################################
# 1. For Bug 2: Qcache_queries_in_cache must be not incremented if a query with
# sleep was first time executed.
# is done. (*)
# 3. NOW() and processlist.time behave "synchronous" to system time and
# show also the "jumps" caused by system time manipulations. (*)
# 4. processlist.time is unsigned, the "next" value below 0 is ~ 4G (*)
# 5. Current processlist.time ~= current real sleep time if the system time
# was not manipulated. (*)
# 6. High system load can cause delays of <= 2 seconds.
# 7. Thanks to Davi for excellent hints and ideas.
#
# (*)
# - information_schema.processlist is not available before MySQL 5.1.
# - Observation of processlist content requires a
# - "worker" session sending the query with "send" and pulling results
# with "reap"
# - session observing the processlist parallel to the worker session
# "send" and "reap" do not work in case of an embedded server.
# Conclusion: Tests based on processlist have too many restrictions.
#
# Solutions for subtests based on TIMEDIFF of values filled via NOW()
# -------------------------------------------------------------------
# Run the following sequence three times
# 1. SELECT <start_time>
# 2. Query with SLEEP
# 3. SELECT <end_time>
# If TIMEDIFF(<end_time>,<start_time>) is at least two times within a
# reasonable range assume that we did not met errors we were looking for.
#
# It is extreme unlikely that we have two system time changes within the
# < 30 seconds runtime. Even if the unlikely happens, there are so
# frequent runs of this test on this or another testing box which will
# catch the problem.
#
--echo #------------------------------------------------------------------------
--echo # Tests for Bug#6760 and Bug#12689
# Number of rows within the intended result set.
SET @row_count = 4;
# Parameter within SLEEP function
SET @sleep_time_per_result_row = 1;
# Maximum acceptable delay caused by high load on testing box
SET @max_acceptable_delay = 2;
# TIMEDIFF = time for query with sleep (mostly the time caused by SLEEP)
# + time for delays caused by high load on testing box
# Ensure that at least a reasonable fraction of TIMEDIFF is belongs to the SLEEP
# by appropriate setting of variables.
# Ensure that any "judging" has a base of minimum three attempts.
# (Test 2 uses all attempts except the first one.)
if (!` SELECT (@sleep_time_per_result_row * @row_count - @max_acceptable_delay >
@sleep_time_per_result_row) AND (@row_count - 1 >= 3)`)
{
--echo # Have to abort because of error in plausibility check
--echo ######################################################
--vertical_results
SELECT @sleep_time_per_result_row * @row_count - @max_acceptable_delay >
@sleep_time_per_result_row AS must_be_1,
@row_count - 1 >= 3 AS must_be_also_1,
@sleep_time_per_result_row, @row_count, @max_acceptable_delay;
exit;
}
SET @@global.query_cache_size = 1024 * 64;
let $Qcache_queries_in_cache_before =
query_get_value(SHOW STATUS LIKE 'Qcache_queries_in_cache', Value, 1);
SELECT 1 as some_value, sleep(1);
let $Qcache_queries_in_cache_after =
query_get_value(SHOW STATUS LIKE 'Qcache_queries_in_cache', Value, 1);
# Show that the query with sleep was not cached via query cache statistics.
--replace_result $Qcache_queries_in_cache_before <Qcache_queries_in_cache_before> $Qcache_queries_in_cache_after <Qcache_queries_in_cache_after>
eval SELECT $Qcache_queries_in_cache_before = $Qcache_queries_in_cache_after
AS "Was the query not cached (= expectation)?";
#
# 2. For Bug 1: Estimation 1
# Real sleep time must exceed the sleep time for just one row.
#
let $sleep_time_per_result_row = 1;
let $row_count = 4;
--disable_warnings
DROP TEMPORARY TABLE IF EXISTS proclist_history;
DROP TABLE IF EXISTS t1;
DROP TEMPORARY TABLE IF EXISTS t_history;
DROP TABLE IF EXISTS t1;
--enable_warnings
CREATE TEMPORARY TABLE proclist_history AS
SELECT 'Bug 1' AS test, 0 AS attempt, NOW() AS observation_time, state, time
FROM information_schema.processlist WHERE 1 = 0;
CREATE TEMPORARY TABLE t_history (attempt SMALLINT,
start_ts DATETIME, end_ts DATETIME,
start_cached INTEGER, end_cached INTEGER);
CREATE TABLE t1 (f1 BIGINT);
let $num = $row_count;
let $num = `SELECT @row_count`;
while ($num)
{
INSERT INTO t1 VALUES (1);
dec $num;
}
eval SET @sleep_time_per_result_row = $sleep_time_per_result_row;
let $sleep_command = SELECT sleep(@sleep_time_per_result_row) FROM t1;
# Set wait_timeout to a useful small value.
let $wait_timeout= `SELECT $row_count * $sleep_time_per_result_row + 5`;
let $wait_condition =
SELECT COUNT(*) >= @sleep_time_per_result_row / 0.1 + 2
FROM proclist_history WHERE test = 'Bug 1';
--echo ----- establish connection con1 (user = root) -----
connect (con1,localhost,root,,);
eval SET @sleep_time_per_result_row = $sleep_time_per_result_row;
let $Qcache_queries_in_cache_before =
query_get_value(SHOW STATUS LIKE 'Qcache_queries_in_cache', Value, 1);
--echo Qcache_queries_in_cache: $Qcache_queries_in_cache_before
--echo # Send query with send, pull server responses later
send;
eval $sleep_command;
#
--echo ----- switch to connection default (user = root) -----
connection default;
#
--disable_query_log
let $wait_counter= `SELECT $wait_timeout * 10`;
let $wait_condition_reps= 0;
while ($wait_counter)
let $loops = 4;
let $num = $loops;
while ($num)
{
let $success= `$wait_condition`;
inc $wait_condition_reps;
let $Qcache_queries_in_cache =
query_get_value(SHOW STATUS LIKE 'Qcache_queries_in_cache', Value, 1);
eval
INSERT INTO t_history
SET attempt = $loops - $num + 1, start_ts = NOW(),
start_cached = $Qcache_queries_in_cache;
SELECT *, SLEEP(@sleep_time_per_result_row) FROM t1;
#
# Do not determine Qcache_queries_in_cache before updating end_ts. The SHOW
# might cost too much time on an overloaded box.
eval
INSERT INTO proclist_history
( test, attempt, observation_time, state, time)
SELECT 'Bug 1', $wait_condition_reps, NOW(), state, time
FROM information_schema.processlist
WHERE info = '$sleep_command';
if ($success)
{
let $wait_counter= 0;
}
if (!$success)
{
real_sleep 0.1;
dec $wait_counter;
}
UPDATE t_history SET end_ts = NOW()
WHERE attempt = $loops - $num + 1;
let $Qcache_queries_in_cache =
query_get_value(SHOW STATUS LIKE 'Qcache_queries_in_cache', Value, 1);
eval
UPDATE t_history SET end_cached = $Qcache_queries_in_cache
WHERE attempt = $loops - $num + 1;
# DEBUG eval SELECT * FROM t_history WHERE attempt = $loops - $num + 1;
dec $num;
}
--enable_query_log
if (!$success)
# 1. The majority of queries with SLEEP must need a reasonable time
# -> SLEEP has an impact on runtime
# = Replacement for original Bug#6760 test
# -> total runtime is clear more needed than for one result row needed
# = Replacement for one of the original Bug#12689 tests
--echo # Test 1: Does the query with SLEEP need a reasonable time?
eval SELECT COUNT(*) > $loops - 1 INTO @aux1 FROM t_history
WHERE TIMEDIFF(end_ts,start_ts) - @sleep_time_per_result_row * @row_count
BETWEEN 0 AND @max_acceptable_delay;
SELECT @aux1 AS "Expect 1";
#
# 2. The majority of queries (the first one must be ignored) with SLEEP must
# need a reasonable time
# -> If we assume that the result of a cached query will be sent back
# immediate, without any sleep, than the query with SLEEP cannot be cached
# (current and intended behaviour for queries with SLEEP).
# -> It could be also not excluded that the query was cached but the server
# honoured somehow the SLEEP. Such a behaviour would be also acceptable.
# = Replacement for one of the original Bug#12689 tests
--echo # Test 2: Does the query with SLEEP need a reasonable time even in case
--echo # of the non first execution?
eval SELECT COUNT(*) > $loops - 1 - 1 INTO @aux2 FROM t_history
WHERE TIMEDIFF(end_ts,start_ts) - @sleep_time_per_result_row * @row_count
BETWEEN 0 AND @max_acceptable_delay
AND attempt > 1;
SELECT @aux2 AS "Expect 1";
#
# 3. The query with SLEEP should be not cached.
# -> SHOW STATUS Qcache_queries_in_cache must be not incremented after
# the execution of the query with SLEEP
--echo # Test 3: The query with SLEEP must be not cached.
eval SELECT COUNT(*) = $loops INTO @aux3 FROM t_history
WHERE end_cached = start_cached;
SELECT @aux3 AS "Expect 1";
#
# Dump the content of t_history if one of the tests failed.
if (`SELECT @aux1 + @aux2 + @aux3 <> 3`)
{
# Estimation 1 had no success - We are most probably on a testing box
# running under high load.
# Try Estimation 2:
let $success = `SELECT MAX(time) > @sleep_time_per_result_row
FROM proclist_history WHERE test = 'Bug 1'`;
}
if (!$success)
{
--echo # ------------------------------------------------------------
--echo # The check for
--echo # Bug#12689: SLEEP() gets incorrectly cached/optimized-away
--echo # failed. None of both estimations are fulfilled.
--echo #
--echo # Dumping debug information
--echo #
--echo # Estimation 1:
eval $wait_condition;
--echo # ------------------------------------------------------------
--echo # Estimation 2:
SELECT MAX(time) > @sleep_time_per_result_row
FROM proclist_history WHERE test = 'Bug 1';
--echo # ------------------------------------------------------------
SELECT attempt, observation_time, state, time FROM proclist_history
WHERE test = 'Bug 1' ORDER BY attempt;
--echo # ------------------------------------------------------------
--echo # Some tests failed, dumping the content of t_history
SELECT * FROM t_history;
}
--echo ----- switch to connection con1 (user = root) -----
connection con1;
--echo # Pull server responses of last query
reap;
#
# 3. For Bug 2: A second execution of the same statement must again show
# the session in state 'User sleep'.
--echo ----- switch to connection con1 (user = root) -----
connection con1;
--echo # Send query with send, pull server responses later
send;
eval $sleep_command;
#
--echo ----- switch to connection default (user = root) -----
connection default;
let $wait_condition = SELECT COUNT(*) FROM information_schema.processlist
WHERE info = '$sleep_command'
AND state = 'User sleep';
--source include/wait_condition.inc
# Simply show that we reached the expected state.
eval $wait_condition;
--echo ----- switch to connection con1 (user = root) -----
connection con1;
--echo # Pull server responses of last query
reap;
--echo ----- switch to connection default and close connection con1 -----
connection default;
disconnect con1;
SET @@global.query_cache_size = default;
DROP TABLE t1;
DROP TEMPORARY TABLE proclist_history;
DROP TEMPORARY TABLE t_history;
SET @@global.query_cache_size = default;
#
# Bug #21466: INET_ATON() returns signed, not unsigned
......@@ -491,7 +388,7 @@ SELECT NAME_CONST('flag',-SQRT(4)) * MAX(a) FROM t1;
DROP TABLE t1;
#
# Bug #27545: erroneous usage of NAME_CONST with a name as the first parameter
# Bug #27545: erroneous usage of NAME_CONST with a name as the first parameter
# resolved against a column name of a derived table hangs the client
#
......
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