Quelle query_cache_sql_prepare.inc
Sprache: Delphi
############### include/query_cache_sql_prepare.inc ################
#
# This isto see how statements prepared via the PREPARE SQL command
# go into the query cache.
# Query cache is abbreviated as"QC"
#
# Last update:
# 2008-05-26 Kostja
# - Add test coverage for automatic statement reprepare
#
# 2007-05-03 ML - Move t/query_cache_sql_prepare.test
# to include/query_cache_sql_prepare.inc
# - Create two toplevel tests sourcing this routine
# - Add tests checking that
# - another connection gets the same amount of QC hits
# - statements running via ps-protocol donot hit QC results
# of preceding sql EXECUTEs
#
--source include/have_query_cache.inc
# embedded can't make more than one connection, which this test needs
-- source include/not_embedded.inc set GLOBAL query_cache_type=ON; set LOCAL query_cache_type=ON;
set @initial_query_cache_size = @@global.query_cache_size; set @@global.query_cache_size=102400;
flush global status;
--disable_warnings
drop table if exists t1;
--enable_warnings
create table t1(c1 int);
insert into t1 values(1),(10),(100);
# First, prepared statements with no parameters
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;
# Mixup tests, where statements without PREPARE.../EXECUTE.... meet statements
# with PREPARE.../EXECUTE.... (text protocol). Both statements have the
# same text. QC hits occur only when both statements use the same protocol.
# The outcome of the test depends on the mysqltest startup options
# - with"--ps-protocol"
# Statements without PREPARE.../EXECUTE.... run as prepared statements
# with binary protocol. Expect to get no QC hits.
# - without any "--<whatever>-protocol"
# Statements without PREPARE.../EXECUTE run as non prepared statements
# with text protocol. Expect to get QC hits.
############################################################################
#
# Statement with PREPARE.../EXECUTE.... first
let $my_stmt= SELECT * FROM t1 WHERE c1 = 100;
eval prepare stmt10 from "$my_stmt";
show status like 'Qcache_hits';
execute stmt10;
show status like 'Qcache_hits';
execute stmt10;
show status like 'Qcache_hits';
eval $my_stmt;
show status like 'Qcache_hits';
connection con1;
eval $my_stmt;
show status like 'Qcache_hits';
connection default;
#
# Statement without PREPARE.../EXECUTE.... first
let $my_stmt= SELECT * FROM t1 WHERE c1 = 1;
eval prepare stmt11 from "$my_stmt";
connection con1;
eval prepare stmt12 from "$my_stmt";
connection default;
eval $my_stmt;
show status like 'Qcache_hits';
eval $my_stmt;
show status like 'Qcache_hits';
execute stmt11;
show status like 'Qcache_hits';
connection con1;
execute stmt12;
show status like 'Qcache_hits';
connection default;
# Query caching also works when statement has parameters
# (BUG#29318 Statements prepared with PREPARE andwith one parameter don't use
# query cache)
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';
execute stmt1 using @a;
show status like 'Qcache_hits';
connection con1; set @a=1;
prepare stmt4 from "select * from t1 where c1=?";
execute stmt4 using @a;
show status like 'Qcache_hits';
# verify that presence of user variables forbids caching
prepare stmt4 from "select @a from t1 where c1=?";
execute stmt4 using @a;
show status like 'Qcache_hits';
execute stmt4 using @a;
show status like 'Qcache_hits';
connection default;
# 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 isnot 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
# Expect to see no additional Qcache_hits. 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';
# The QC is global = affects also other connections.
# Expect to see no additional Qcache_hits.
connection con1;
execute stmt3;
show status like 'Qcache_hits';
execute stmt3;
show status like 'Qcache_hits';
execute stmt3;
show status like 'Qcache_hits';
#
# then QC is re-enabled for more EXECUTE.
connection default; set global query_cache_size=102400;
# Expect to see additional Qcache_hits.
# The fact that the QC was temporary disabled should have no affect
# except that the first execute will not hit results from the
# beginning of the test (because QC has been emptied meanwhile by
# setting its size to0).
execute stmt1;
show status like 'Qcache_hits';
execute stmt1;
show status like 'Qcache_hits';
execute stmt1;
show status like 'Qcache_hits';
# The QC is global = affects also other connections.
connection con1;
execute stmt3;
show status like 'Qcache_hits';
execute stmt3;
show status like 'Qcache_hits';
execute stmt3;
show status like 'Qcache_hits';
connection default;
#
# then QC is re-disabled for more EXECUTE.
# Expect to see no additional Qcache_hits.
# The fact that the QC was temporary enabled should have no affect. 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';
# The QC is global = affects also other connections.
connection con1;
execute stmt3;
show status like 'Qcache_hits';
execute stmt3;
show status like 'Qcache_hits';
execute stmt3;
show status like 'Qcache_hits';
#
connection default;
# QC is disabled at PREPARE set global query_cache_size=0;
prepare stmt1 from "select * from t1 where c1=10";
connection con1;
prepare stmt3 from "select * from t1 where c1=10";
connection default;
# then QC is enabled at EXECUTE set global query_cache_size=102400;
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';
# The QC is global = affects also other connections.
connection con1;
show status like 'Qcache_hits';
execute stmt3;
show status like 'Qcache_hits';
execute stmt3;
show status like 'Qcache_hits';
execute stmt3;
show status like 'Qcache_hits';
connection default;
#
# 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=102400;
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';
--enable_ps2_protocol
drop table t1;
disconnect con1;
#
# Bug #25843 Changing default database between PREPARE and EXECUTE of statement
# breaks binlog.
#
# There were actually two problems discovered by this bug:
#
# 1. Default (current) database isnot fixed at the creation time.
# That leads to wrong output of DATABASE() function.
#
# 2. Database attributes (@@collation_database) are not fixed at the creation
# time. That leads to wrong resultset.
#
# Binlog breakage and Query Cache wrong output happened because of the first
# problem.
#
--echo ########################################################################
--echo #
--echo # BUG#25843: Changing default database between PREPARE and EXECUTE of
--echo # statement breaks binlog.
--echo #
--echo ########################################################################
--echo
PREPARE stmt_c_1 FROM 'SELECT DATABASE(), @@collation_database';
--echo
use mysqltest2;
--echo
PREPARE stmt_c_2 FROM 'SELECT DATABASE(), @@collation_database';
--echo
DROP DATABASE mysqltest2;
--echo
SELECT DATABASE(), @@collation_database;
# -- Here we have: current db: NULL; stmt db: mysqltest1;
--echo
EXECUTE stmt_c_1;
--echo
SELECT DATABASE(), @@collation_database;
# -- Here we have: current db: NULL; stmt db: mysqltest2 (non-existent);
--echo
EXECUTE stmt_c_2;
--echo
SELECT DATABASE(), @@collation_database;
# -- Create prepared statement, which has no current database.
--echo
PREPARE stmt_c_3 FROM 'SELECT DATABASE(), @@collation_database';
# -- Here we have: current db: NULL; stmt db: NULL;
--echo
EXECUTE stmt_c_3;
--echo
use mysqltest1;
# -- Here we have: current db: mysqltest1; stmt db: mysqltest2 (non-existent);
--echo
EXECUTE stmt_c_2;
--echo
SELECT DATABASE(), @@collation_database;
# -- Here we have: current db: mysqltest1; stmt db: NULL;
--echo
EXECUTE stmt_c_3;
--echo
SELECT DATABASE(), @@collation_database;
--echo
DROP DATABASE mysqltest1;
--echo
use test;
--echo
--echo ########################################################################
--echo #
--echo # Bug#27430 Crash in subquery code when in PS and table DDL changed
--echo # after PREPARE
--echo # Check the effect of automatic reprepare on query cache
--echo #
--echo ########################################################################
--disable_warnings
drop table if exists t1;
--enable_warnings
create table t1 (a varchar(255));
insert into t1 (a) values ("Pack my box with five dozen liquor jugs.");
flush global status;
prepare stmt from "select a from t1";
execute stmt; set @@global.query_cache_size=0;
alter table t1 add column b int;
execute stmt; set @@global.query_cache_size=102400;
execute stmt;
execute stmt;
--echo #
--echo # Sic: ALTER TABLE caused an automatic reprepare
--echo # of the prepared statement. Since the query cache was disabled
--echo # at the time of reprepare, the new prepared statement doesn't
--echo # work with it.
--echo #
show status like 'Qcache_hits';
show status like 'Qcache_queries_in_cache';
--echo # Cleanup
deallocate prepare stmt;
drop table t1;
set @@global.query_cache_size=@initial_query_cache_size;
flush status; # reset Qcache status variables for next tests set GLOBAL query_cache_type=default;
Messung V0.5 in Prozent
¤ Dauer der Verarbeitung: 0.12 Sekunden
(vorverarbeitet am 2026-10-08)
¤
Die Informationen auf dieser Webseite wurden
nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit,
noch Qualität der bereit gestellten Informationen zugesichert.
Bemerkung:
Die farbliche Syntaxdarstellung und die Messung sind noch experimentell.