mariadb/mysql-test/t/query_cache_sql_prepare.test

# This is to see how statements prepared via the PREPARE SQL command
# go into the query cache: if using parameters they cannot; if not
# using parameters they can.
# Query cache is abbreviated as "QC"

-- source include/have_query_cache.inc
# embedded can't make more than one connection, which this test needs
-- source include/not_embedded.inc

connect (con1,localhost,root,,test,$MASTER_MYPORT,);
connection default;

set global query_cache_size=100000;
flush status;
create table t1(c1 int);
insert into t1 values(1),(10),(100);

# Prepared statements has no parameters, query caching should happen
prepare stmt1 from "select * from t1 where c1=10";
show status like 'Qcache_hits';
execute stmt1;
show status like 'Qcache_hits';
execute stmt1;
show status like 'Qcache_hits';
execute stmt1;
show status like 'Qcache_hits';
# Another prepared statement (same text, same connection), should hit the QC
prepare stmt2 from "select * from t1 where c1=10";
execute stmt2;
show status like 'Qcache_hits';
execute stmt2;
show status like 'Qcache_hits';
execute stmt2;
show status like 'Qcache_hits';
# Another prepared statement (same text, other connection), should hit the QC
connection con1;
prepare stmt3 from "select * from t1 where c1=10";
execute stmt3;
show status like 'Qcache_hits';
execute stmt3;
show status like 'Qcache_hits';
execute stmt3;
show status like 'Qcache_hits';
connection default;
# A non-prepared statement (same text, same connection), should hit
# the QC (as it uses the text protocol like SQL EXECUTE).
# But if it uses the binary protocol, it will not hit. So we make sure
# that it uses the text protocol:
-- disable_ps_protocol
select * from t1 where c1=10;
show status like 'Qcache_hits';
 # A non-prepared statement (same text, other connection), should hit
# the QC. To test that it hits the result of SQL EXECUTE, we need to
# empty/repopulate the QC (to remove the result from the non-prepared
# SELECT just above).
flush tables;
execute stmt1;
show status like 'Qcache_hits';
connection con1;
select * from t1 where c1=10;
show status like 'Qcache_hits';
-- enable_ps_protocol
connection default;

# Prepared statement has parameters, query caching should not happen
prepare stmt1 from "select * from t1 where c1=?";
show status like 'Qcache_hits';
set @a=1;
execute stmt1 using @a;
show status like 'Qcache_hits';
set @a=100;
execute stmt1 using @a;
show status like 'Qcache_hits';
set @a=10;
execute stmt1 using @a;
show status like 'Qcache_hits';

# See if enabling/disabling the query cache between PREPARE and
# EXECUTE is an issue; the expected result is that the query cache
# will not be used.
# Indeed, decision to read/write the query cache is taken at PREPARE
# time, so if the query cache was disabled at PREPARE time then no
# execution of the statement will read/write the query cache.
# If the query cache was enabled at PREPARE time, but disabled at
# EXECUTE time, at EXECUTE time the query cache internal functions do
# nothing so again the query cache is not read/written. But if the
# query cache is re-enabled before another execution then that
# execution will read/write the query cache.

# QC is enabled at PREPARE
prepare stmt1 from "select * from t1 where c1=10";
# then QC is disabled at EXECUTE
set global query_cache_size=0;
show status like 'Qcache_hits';
execute stmt1;
show status like 'Qcache_hits';
execute stmt1;
show status like 'Qcache_hits';
execute stmt1;
show status like 'Qcache_hits';
# then QC is re-enabled for more EXECUTE.
set global query_cache_size=100000;
# Note that this execution will not hit results from the
# beginning of the test (because QC has been emptied meanwhile by
# setting its size to 0).
execute stmt1;
show status like 'Qcache_hits';
execute stmt1;
show status like 'Qcache_hits';
execute stmt1;
show status like 'Qcache_hits';

# QC is disabled at PREPARE
set global query_cache_size=0;
prepare stmt1 from "select * from t1 where c1=10";
# then QC is enabled at EXECUTE
set global query_cache_size=100000;
show status like 'Qcache_hits';
execute stmt1;
show status like 'Qcache_hits';
execute stmt1;
show status like 'Qcache_hits';
execute stmt1;
show status like 'Qcache_hits';

# QC is disabled at PREPARE
set global query_cache_size=0;
prepare stmt1 from "select * from t1 where c1=?";
# then QC is enabled at EXECUTE
set global query_cache_size=100000;
show status like 'Qcache_hits';
set @a=1;
execute stmt1 using @a;
show status like 'Qcache_hits';
set @a=100;
execute stmt1 using @a;
show status like 'Qcache_hits';
set @a=10;
execute stmt1 using @a;
show status like 'Qcache_hits';


drop table t1;

set global query_cache_size=0;
flush status; # reset Qcache status variables for next tests