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mariadb/mysql-test/suite/funcs_1/datadict/processlist_val.inc
Dmitry Lenev eba5d30e67 Implement new type-of-operation-aware metadata locks.
Add a wait-for graph based deadlock detector to the
MDL subsystem.

Fixes bug #46272 "MySQL 5.4.4, new MDL: unnecessary deadlock" and
bug #37346 "innodb does not detect deadlock between update and
alter table".

The first bug manifested itself as an unwarranted abort of a
transaction with ER_LOCK_DEADLOCK error by a concurrent ALTER
statement, when this transaction tried to repeat use of a
table, which it has already used in a similar fashion before
ALTER started.

The second bug showed up as a deadlock between table-level
locks and InnoDB row locks, which was "detected" only after
innodb_lock_wait_timeout timeout.

A transaction would start using the table and modify a few
rows.
Then ALTER TABLE would come in, and start copying rows
into a temporary table. Eventually it would stumble on
the modified records and get blocked on a row lock.
The first transaction would try to do more updates, and get
blocked on thr_lock.c lock.
This situation of circular wait would only get resolved
by a timeout.

Both these bugs stemmed from inadequate solutions to the
problem of deadlocks occurring between different
locking subsystems.

In the first case we tried to avoid deadlocks between metadata
locking and table-level locking subsystems, when upgrading shared
metadata lock to exclusive one.
Transactions holding the shared lock on the table and waiting for
some table-level lock used to be aborted too aggressively.

We also allowed ALTER TABLE to start in presence of transactions
that modify the subject table. ALTER TABLE acquires
TL_WRITE_ALLOW_READ lock at start, and that block all writes
against the table (naturally, we don't want any writes to be lost
when switching the old and the new table). TL_WRITE_ALLOW_READ
lock, in turn, would block the started transaction on thr_lock.c
lock, should they do more updates. This, again, lead to the need
to abort such transactions.

The second bug occurred simply because we didn't have any
mechanism to detect deadlocks between the table-level locks
in thr_lock.c and row-level locks in InnoDB, other than
innodb_lock_wait_timeout.

This patch solves both these problems by moving lock conflicts
which are causing these deadlocks into the metadata locking
subsystem, thus making it possible to avoid or detect such
deadlocks inside MDL.

To do this we introduce new type-of-operation-aware metadata
locks, which allow MDL subsystem to know not only the fact that
transaction has used or is going to use some object but also what
kind of operation it has carried out or going to carry out on the
object.

This, along with the addition of a special kind of upgradable
metadata lock, allows ALTER TABLE to wait until all
transactions which has updated the table to go away.
This solves the second issue.
Another special type of upgradable metadata lock is acquired
by LOCK TABLE WRITE. This second lock type allows to solve the
first issue, since abortion of table-level locks in event of
DDL under LOCK TABLES becomes also unnecessary.

Below follows the list of incompatible changes introduced by
this patch:

- From now on, ALTER TABLE and CREATE/DROP TRIGGER SQL (i.e. those
  statements that acquire TL_WRITE_ALLOW_READ lock)
  wait for all transactions which has *updated* the table to
  complete.

- From now on, LOCK TABLES ... WRITE, REPAIR/OPTIMIZE TABLE
  (i.e. all statements which acquire TL_WRITE table-level lock) wait
  for all transaction which *updated or read* from the table
  to complete.
  As a consequence, innodb_table_locks=0 option no longer applies
  to LOCK TABLES ... WRITE.

- DROP DATABASE, DROP TABLE, RENAME TABLE no longer abort
  statements or transactions which use tables being dropped or
  renamed, and instead wait for these transactions to complete.

- Since LOCK TABLES WRITE now takes a special metadata lock,
  not compatible with with reads or writes against the subject table
  and transaction-wide, thr_lock.c deadlock avoidance algorithm
  that used to ensure absence of deadlocks between LOCK TABLES
  WRITE and other statements is no longer sufficient, even for
  MyISAM. The wait-for graph based deadlock detector of MDL
  subsystem may sometimes be necessary and is involved. This may
  lead to ER_LOCK_DEADLOCK error produced for multi-statement
  transactions even if these only use MyISAM:

  session 1:         session 2:
  begin;

  update t1 ...      lock table t2 write, t1 write;
                     -- gets a lock on t2, blocks on t1

  update t2 ...
  (ER_LOCK_DEADLOCK)

- Finally,  support of LOW_PRIORITY option for LOCK TABLES ... WRITE
  was abandoned.
  LOCK TABLE ... LOW_PRIORITY WRITE from now on has the same
  priority as the usual LOCK TABLE ... WRITE.
  SELECT HIGH PRIORITY no longer trumps LOCK TABLE ... WRITE  in
  the wait queue.

- We do not take upgradable metadata locks on implicitly
  locked tables. So if one has, say, a view v1 that uses
  table t1, and issues:
  LOCK TABLE v1 WRITE;
  FLUSH TABLE t1; -- (or just 'FLUSH TABLES'),
  an error is produced.
  In order to be able to perform DDL on a table under LOCK TABLES,
  the table must be locked explicitly in the LOCK TABLES list.

mysql-test/include/handler.inc:
  Adjusted test case to trigger an execution path on which bug 41110
  "crash with handler command when used concurrently with alter
  table" and bug 41112 "crash in mysql_ha_close_table/get_lock_data
  with alter table" were originally discovered. Left old test case
  which no longer triggers this execution path for the sake of
  coverage.
  Added test coverage for HANDLER SQL statements and type-aware
  metadata locks.
  Added a test for the global shared lock and HANDLER SQL.
  Updated tests to take into account that the old simple deadlock
  detection heuristics was replaced with a graph-based deadlock
  detector.
mysql-test/r/debug_sync.result:
  Updated results (see debug_sync.test).
mysql-test/r/handler_innodb.result:
  Updated results (see handler.inc test).
mysql-test/r/handler_myisam.result:
  Updated results (see handler.inc test).
mysql-test/r/innodb-lock.result:
  Updated results (see innodb-lock.test).
mysql-test/r/innodb_mysql_lock.result:
  Updated results (see innodb_mysql_lock.test).
mysql-test/r/lock.result:
  Updated results (see lock.test).
mysql-test/r/lock_multi.result:
  Updated results (see lock_multi.test).
mysql-test/r/lock_sync.result:
  Updated results (see lock_sync.test).
mysql-test/r/mdl_sync.result:
  Updated results (see mdl_sync.test).
mysql-test/r/sp-threads.result:
  SHOW PROCESSLIST output has changed due to the fact that waiting
  for LOCK TABLES WRITE now happens within metadata locking
  subsystem.
mysql-test/r/truncate_coverage.result:
  Updated results (see truncate_coverage.test).
mysql-test/suite/funcs_1/datadict/processlist_val.inc:
  SELECT FROM I_S.PROCESSLIST output has changed due to fact that
  waiting for LOCK TABLES WRITE now happens within metadata locking
  subsystem.
mysql-test/suite/funcs_1/r/processlist_val_no_prot.result:
  SELECT FROM I_S.PROCESSLIST output has changed due to fact that
  waiting for LOCK TABLES WRITE now happens within metadata locking
  subsystem.
mysql-test/suite/rpl/t/rpl_sp.test:
  Updated to a new SHOW PROCESSLIST state name.
mysql-test/t/debug_sync.test:
  Use LOCK TABLES READ instead of LOCK TABLES WRITE as the latter
  no longer allows to trigger execution path involving waiting on
  thr_lock.c lock and therefore reaching debug sync-point covered
  by this test.
mysql-test/t/innodb-lock.test:
  Adjusted test case to the fact that innodb_table_locks=0 option is
  no longer supported, since LOCK TABLES WRITE handles all its
  conflicts within MDL subsystem.
mysql-test/t/innodb_mysql_lock.test:
  Added test for bug #37346 "innodb does not detect deadlock between
  update and alter table".
mysql-test/t/lock.test:
  Added test coverage which checks the fact that we no longer support
  DDL under LOCK TABLES on tables which were locked implicitly.
  Adjusted existing test cases accordingly.
mysql-test/t/lock_multi.test:
  Added test for bug #46272 "MySQL 5.4.4, new MDL: unnecessary
  deadlock".  Adjusted other test cases to take into account the
  fact that waiting for LOCK TABLES ... WRITE now happens within MDL
  subsystem.
mysql-test/t/lock_sync.test:
  Since LOCK TABLES ... WRITE now takes SNRW metadata lock for
  tables locked explicitly we have to implicitly lock InnoDB tables
  (through view) to trigger the table-level lock conflict between
  TL_WRITE and TL_WRITE_ALLOW_WRITE.
mysql-test/t/mdl_sync.test:
  Added basic test coverage for type-of-operation-aware metadata
  locks. Also covered with tests some use cases involving HANDLER
  statements in which a deadlock could arise.
  Adjusted existing tests to take type-of-operation-aware MDL into
  account.
mysql-test/t/multi_update.test:
  Update to a new SHOW PROCESSLIST state name.
mysql-test/t/truncate_coverage.test:
  Adjusted test case after making LOCK TABLES WRITE to wait until
  transactions that use the table to be locked are completed.
  Updated to the changed name of DEBUG_SYNC point.
sql/handler.cc:
  Global read lock functionality has been
  moved into a class.
sql/lock.cc:
  Global read lock functionality has been
  moved into a class.
  Updated code to use the new MDL API.
sql/mdl.cc:
  Introduced new type-of-operation aware metadata locks.
  To do this:
  - Changed MDL_lock to use one list for waiting requests and one
    list for granted requests. For each list, added a bitmap
    that holds information what lock types a list contains.
    Added a helper class MDL_lock::List to manipulate with granted
    and waited lists while keeping the bitmaps in sync
    with list contents.
  - Changed lock-compatibility functions to use bitmaps that
    define compatibility.
  - Introduced a graph based deadlock detector inspired by
    waiting_threads.c from Maria implementation.
  - Now that we have a deadlock detector, and no longer have
    a global lock to protect individual lock objects, but rather
    use an rw lock per object, removed redundant code for upgrade,
    and the global read lock. Changed the MDL API to
    no longer require the caller to acquire the global
    intention exclusive lock by means of a separate method.
    Removed a few more methods that became redundant.
  - Removed deadlock detection heuristic, it has been made
    obsolete by the deadlock detector.
  - With operation-type-aware metadata locks, MDL subsystem has
    become aware of potential conflicts between DDL and open
    transactions. This made it possible to remove calls to
    mysql_abort_transactions_with_shared_lock() from acquisition
    paths for exclusive lock and lock upgrade. Now we can simply
    wait for these transactions to complete without fear of
    deadlock. Function mysql_lock_abort() has also become
    unnecessary for all conflicting cases except when a DDL
    conflicts with a connection that has an open HANDLER.
sql/mdl.h:
  Introduced new type-of-operation aware metadata locks.
  Introduced a graph based deadlock detector and supporting
  methods.
  Added comments.
  God rid of redundant API calls.
  Renamed m_lt_or_ha_sentinel to m_trans_sentinel,
  since now it guards the global read lock as well as
  LOCK TABLES and HANDLER locks.
sql/mysql_priv.h:
  Moved the global read lock functionality into a
  class.
  Added MYSQL_OPEN_FORCE_SHARED_MDL flag which forces
  open_tables() to take MDL_SHARED on tables instead of
  metadata locks specified in the parser. We use this to
  allow PREPARE run concurrently in presence of
  LOCK TABLES ... WRITE.
  Added signature for find_table_for_mdl_ugprade().
sql/set_var.cc:
  Global read lock functionality has been
  moved into a class.
sql/sp_head.cc:
  When creating TABLE_LIST elements for prelocking or
  system tables set the type of request for metadata
  lock according to the operation that will be performed
  on the table.
sql/sql_base.cc:
  - Updated code to use the new MDL API.
  - In order to avoid locks starvation we take upgradable
    locks all at once. As result implicitly locked tables no
    longer get an upgradable lock. Consequently DDL and FLUSH
    TABLES for such tables is prohibited.
    find_write_locked_table() was replaced by
    find_table_for_mdl_upgrade() function.
    open_table() was adjusted to return TABLE instance with
    upgradable ticket when necessary.
  - We no longer wait for all locks on OT_WAIT back off
    action -- only on the lock that caused the wait
    conflict. Moreover, now we distinguish cases when we
    have to wait due to conflict in MDL and old version
    of table in TDC.
  - Upate mysql_notify_threads_having_share_locks()
    to only abort thr_lock.c waits of threads that
    have open HANDLERs, since lock conflicts with only
    these threads now can lead to deadlocks not detectable
    by the MDL deadlock detector.
  - Remove mysql_abort_transactions_with_shared_locks()
    which is no longer needed.
sql/sql_class.cc:
  Global read lock functionality has been moved into a class.
  Re-arranged code in THD::cleanup() to simplify assert.
sql/sql_class.h:
  Introduced class to incapsulate global read lock
  functionality.
  Now sentinel in MDL subsystem guards the global read lock
  as well as LOCK TABLES and HANDLER locks. Adjusted code
  accordingly.
sql/sql_db.cc:
  Global read lock functionality has been moved into a class.
sql/sql_delete.cc:
  We no longer acquire upgradable metadata locks on tables
  which are locked by LOCK TABLES implicitly. As result
  TRUNCATE TABLE is no longer allowed for such tables.
  Updated code to use the new MDL API.
sql/sql_handler.cc:
  Inform MDL_context about presence of open HANDLERs.
  Since HANLDERs break MDL protocol by acquiring table-level
  lock while holding only S metadata lock on a table MDL
  subsystem should take special care about such contexts (Now
  this is the only case when mysql_lock_abort() is used).
sql/sql_parse.cc:
  Global read lock functionality has been moved into a class.
  Do not take upgradable metadata locks when opening tables
  for CREATE TABLE SELECT as it is not necessary and limits
  concurrency.
  When initializing TABLE_LIST objects before adding them
  to the table list set the type of request for metadata lock
  according to the operation that will be performed on the
  table.
  We no longer acquire upgradable metadata locks on tables
  which are locked by LOCK TABLES implicitly. As result FLUSH
  TABLES is no longer allowed for such tables.
sql/sql_prepare.cc:
  Use MYSQL_OPEN_FORCE_SHARED_MDL flag when opening
  tables during PREPARE. This allows PREPARE to run
  concurrently in presence of LOCK TABLES ... WRITE.
sql/sql_rename.cc:
  Global read lock functionality has been moved into a class.
sql/sql_show.cc:
  Updated code to use the new MDL API.
sql/sql_table.cc:
  Global read lock functionality has been moved into a class.
  We no longer acquire upgradable metadata locks on tables
  which are locked by LOCK TABLES implicitly. As result DROP
  TABLE is no longer allowed for such tables.
  Updated code to use the new MDL API.
sql/sql_trigger.cc:
  Global read lock functionality has been moved into a class.
  We no longer acquire upgradable metadata locks on tables
  which are locked by LOCK TABLES implicitly. As result
  CREATE/DROP TRIGGER is no longer allowed for such tables.
  Updated code to use the new MDL API.
sql/sql_view.cc:
  Global read lock functionality has been moved into a class.
  Fixed results of wrong merge that led to misuse of GLR API.
  CREATE VIEW statement is not a commit statement.
sql/table.cc:
  When resetting TABLE_LIST objects for PS or SP re-execution
  set the type of request for metadata lock according to the
  operation that will be performed on the table. Do the same
  in auxiliary function initializing metadata lock requests
  in a table list.
sql/table.h:
  When initializing TABLE_LIST objects set the type of request
  for metadata lock according to the operation that will be
  performed on the table.
sql/transaction.cc:
  Global read lock functionality has been moved into a class.
2010-02-01 14:43:06 +03:00

466 lines
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PHP

########### suite/funcs_1/datadict/processlist_val.inc #########################
# #
# Testing of values within INFORMATION_SCHEMA.PROCESSLIST #
# #
# Ensure that the values fit to the current state of the connection and #
# especially that they change if a connection does nothing or runs some SQL. #
# runs some SQL. #
# Examples: #
# - change the default database #
# - send some period of time no SQL command to the server #
# - send a long running query #
# #
# Note(mleich): #
# 1. Please inform me if this test fails because of timing problems. #
# 2. Storage engine variants of this test do not make sense. #
# - I_S tables use the MEMORY storage engine whenever possible. #
# - There are some I_S tables which need column data types which are not #
# supported by MEMORY. Example: LONGTEXT/BLOB #
# MyISAM will be used for such tables. #
# The column PROCESSLIST.INFO is of data type LONGTEXT ----> MyISAM #
# - There is no impact of the GLOBAL(server) or SESSION default storage #
# engine setting on the engine used for I_S tables. #
# That means we cannot get NDB or InnoDB instead. #
# 3. The SHOW (FULL) PROCESSLIST command are for comparison. #
# The main test target is INFORMATION_SCHEMA.PROCESSLIST ! #
# 4. Attention: #
# The values of the PROCESSLIST columns HOST and TIME tend to cause #
# problems and therefore their printing has to be suppressed. #
# Examples of the exact values: #
# HOST: 'localhost' (UNIX derivates) #
# 'localhost:<varying_port>' (WINDOWS) #
# TIME: In many cases within this test 0 seconds but if the testing box is #
# overloaded we might get up to 2 seconds. #
# Solution: #
# --replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME> #
# 5. How to debug the script? #
# <graphical diff tool> \ #
# suite/funcs_1/datadict/processlist_val.inc \ #
# <Result|Reject|Log file> #
# I tweaked a lot of the script lines around "echo" so that you will get a #
# lot of useful synchronisation. #
# #
# Creation: #
# 2007-08-09 mleich Implement this test as part of #
# WL#3982 Test information_schema.processlist #
# #
# Last Modification: #
# 2008-07-04 mleich Fix for #
# Bug#37853 Test "funcs_1.processlist_val_ps" fails in #
# various ways #
# - issues with printing of port (Win only) #
# - too optimistic assumptions about timing #
# + corrections of logic in poll routines #
# + minor improvements #
################################################################################
# Basic preparations
--error 0, ER_CANNOT_USER
DROP USER test_user@'localhost';
CREATE USER test_user@'localhost';
GRANT ALL ON *.* TO test_user@'localhost';
REVOKE PROCESS ON *.* FROM test_user@'localhost';
SET PASSWORD FOR test_user@'localhost' = PASSWORD('ddictpass');
--disable_warnings
DROP TABLE IF EXISTS test.t1;
--enable_warnings
CREATE TABLE test.t1 (f1 BIGINT);
USE test;
echo
# Show the definition of the PROCESSLIST table
#--------------------------------------------------------------------------
;
SHOW CREATE TABLE INFORMATION_SCHEMA.PROCESSLIST;
echo
# Ensure that the information about the own connection is correct.
#--------------------------------------------------------------------------
;
# Expected values
# - USER = 'root'
# - HOST (printed value is unified), the exact values are often like
# UNIX: 'localhost'
# WIN: 'localhost:<some port>'
# - DB = 'test'
# - Command IN (no protocol -> 'Query', ps-protocol -> 'Execute')
# - TIME (printed value will be unified), the exact values are like
# "normal" load: 0 (seconds)
# "heavy" load: 1 or more (seconds)
# - State 'executing'
# - INFO must contain the corresponding SHOW/SELECT PROCESSLIST
#
# 1. Just dump what we get
--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME>
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME>
SHOW FULL PROCESSLIST;
#
# Determine the connection id of the current connection (default)
SET @default_id = CONNECTION_ID();
#
# 2. There must be exact one connection with @default_id;
SELECT COUNT(*) = 1 AS "Expect exact one connection with this id"
FROM INFORMATION_SCHEMA.PROCESSLIST WHERE ID = @default_id;
#
# 3. Check the remaining stuff
SELECT COUNT(*) = 1 AS "Expect 1"
FROM INFORMATION_SCHEMA.PROCESSLIST WHERE ID = @default_id
AND USER = 'root' AND DB = 'test' AND Command IN('Query','Execute')
AND State = 'executing';
#
# 4. Change the DB
USE information_schema;
SELECT COUNT(*) = 1 AS "Is the DB correct?"
FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE ID = @default_id AND DB = 'information_schema';
#
# 5. Change the statement
let $my_statement =
SELECT @my_info := INFO FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE ID = @default_id;
eval $my_statement;
eval
SELECT @my_info = '$my_statement'
AS 'Is the content of PROCESSLIST.INFO correct?';
#
# 6. TIME must have a reasonable value
SELECT COUNT(*) = 1 AS "Has TIME a reasonable value?"
FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE ID = @default_id AND 0 <= TIME < 10;
echo
# Ensure that the information about an inactive connection is correct.
#--------------------------------------------------------------------------
;
echo
# ----- establish connection con1 (user = test_user) -----
;
connect (con1,localhost,test_user,ddictpass,information_schema);
#
echo
# ----- switch to connection default (user = root) -----
;
connection default;
# We have now a second connection.
# First working phase for the new connection is with Command = 'Connect'.
# This is a very short phase and the likelihood to meet it is
# - nearly zero on average boxes with low parallel load
# - around some percent on weak or overloaded boxes
# (Bug#32153 Status output differs - scheduling ?)
# Therefore we do not try to catch this state.
# We poll till we reach the long lasting phase with Command = 'Sleep'.
# - USER = 'test_user'
# - DB = 'information_schema'
# - Command = 'Sleep'
# - State is empty
# - INFO IS NULL
echo
# Poll till the connection con1 is in state COMMAND = 'Sleep'.
;
let $wait_timeout= 10;
let $wait_condition= SELECT COUNT(*) = 1 FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE COMMAND = 'Sleep' AND USER = 'test_user';
--source include/wait_condition.inc
# 1. Just dump what we get
--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME>
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME>
SHOW FULL PROCESSLIST;
#
# Pull ID and TIME of the second connection
SELECT ID,TIME INTO @test_user_con1_id,@time FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE COMMAND = 'Sleep' AND USER = 'test_user';
#
# 2. The second connection must (behaviour at least since 2007) have an
# ID = ID_of_previous_connection + 1
SELECT @test_user_con1_id = @default_id + 1
AS "Did we got the next higher PROCESSLIST ID?";
#
# 3. TIME must have a reasonable value
SELECT 0 <= @time < 10 AS "Has TIME a reasonable value?";
#
# 4. HOST must be for both connections similar (varying port on Win)
SELECT COUNT(*) = 2 AS "Is HOST LIKE 'localhost%'?"
FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE HOST LIKE 'localhost%';
#
# 5. Check the remaining stuff
SELECT COUNT(*) = 1 AS "Expect 1"
FROM INFORMATION_SCHEMA.PROCESSLIST WHERE ID = @test_user_con1_id
AND USER = 'test_user' AND DB = 'information_schema'
AND Command = 'Sleep' AND State = '' AND INFO IS NULL;
#
# 6. Check that TIME increases
let $wait_timeout= 10;
let $wait_condition= SELECT COUNT(*) = 1 FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE COMMAND = 'Sleep' AND USER = 'test_user'
AND TIME > @time;
--source include/wait_condition.inc
echo
# Ensure that the user test_user sees only connections with his username
# because he has not the PROCESS privilege.
#----------------------------------------------------------------------------
;
echo
# ----- switch to connection con1 (user = test_user) -----
;
connection con1;
--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME>
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME>
SHOW FULL PROCESSLIST;
echo
# Ensure that the user test_user sees all connections with his username.
#----------------------------------------------------------------------------
;
echo
----- establish connection con2 (user = test_user) ------
;
connect (con2,localhost,test_user,ddictpass,information_schema);
echo
# ----- switch to connection default (user = root) -----
;
connection default;
# If the testing box is under heavy load we might see within some of the
# next queries connection
# con2 with Command = 'Connect'
# con1 with INFO = 'SHOW FULL PROCESSLIST' and STATE = 'Writing to net'
# Both phases are too short to be checked.
echo
# Poll till all connections of 'test_user' are in a state with COMMAND = 'Sleep'
;
let $wait_condition= SELECT COUNT(*) = 2 FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE USER = 'test_user' AND COMMAND = 'Sleep';
--source include/wait_condition.inc
echo
# ----- switch to connection con2 (user = test_user) -----
;
connection con2;
# Just dump what we get
--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME>
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME>
SHOW FULL PROCESSLIST;
#
echo
# ----- switch to connection default (user = root) -----
;
connection default;
# Pull the ID of con2, we will need it later
SELECT ID INTO @test_user_con2_id FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE ID <> @test_user_con1_id
AND USER = 'test_user' AND DB = 'information_schema';
echo
# Ensure we get correct information about a connection during work
#----------------------------------------------------------------------------
;
echo
# ----- switch to connection con2 (user = test_user) -----
;
connection con2;
# "Organise" a long running command to be observed by the root user.
echo
# Send a long enough running statement to the server, but do not
# wait till the result comes back.
;
# Worst case scenario (=high I/O load on testing box):
# - My experience:
# Up to 2 seconds runtime per SELECT ... FROM INFORMATION_SCHEMA.PROCESSLIST
# in rare cases.
# - The following sequence contains ~ 4 of such SELECTs
# Therefore we sleep 10 seconds.
let $sleep_command =
SELECT sleep(10), 17;
send;
eval $sleep_command;
#
echo
# ----- switch to connection default (user = root) -----
;
connection default;
echo
# Poll till connection con2 is in state 'User sleep'.
;
# Expect to see within the processlist the other connection just during
# statement execution.
# - USER = 'test_user'
# - DB = 'information_schema'
# - Command = 'Query'(run without --ps-protocol)/'Execute' (run --ps-protocol)
# - TIME >= 0
# - State = 'User sleep'
# - INFO = $sleep_command
let $wait_condition=
SELECT COUNT(*) FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE ID = @test_user_con2_id AND Command IN('Query','Execute')
AND State = 'User sleep' AND INFO IS NOT NULL ;
--source include/wait_condition.inc
# 1. Just dump what we get
--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME>
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME>
SHOW FULL PROCESSLIST;
#
# Pull some information about the connection con2
SELECT STATE, TIME, INFO INTO @state, @time, @info
FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE ID = @test_user_con2_id;
# 2. TIME must have a reasonable value
SELECT 0 <= @time < 10 AS "Has TIME a reasonable value?";
# 3. STATE must be 'User sleep'
SELECT @state = 'User sleep' AS "Has STATE the expected value?";
# 4. INFO must fit
eval SELECT @info = '$sleep_command' AS "Has INFO the expected value?";
# 5. Check that TIME increases
let $wait_timeout= 10;
let $wait_condition= SELECT COUNT(*) = 1 FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE ID = @test_user_con2_id AND INFO IS NOT NULL AND TIME > @time;
--source include/wait_condition.inc
echo
# ----- switch to connection con2 (user = testuser) -----
;
connection con2;
echo
# Pull("reap") the result set from the statement executed with "send".
;
reap;
echo
# ----- switch to connection default (user = root) -----
;
connection default;
echo
# Poll till all connections of 'test_user' are in a state with COMMAND = 'Sleep'
;
let $wait_timeout= 10;
let $wait_condition= SELECT COUNT(*) = 2 FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE COMMAND = 'Sleep' AND USER = 'test_user';
--source include/wait_condition.inc
echo
# Ensure that we see that a connection "hangs" when colliding with a
# WRITE TABLE LOCK
#----------------------------------------------------------------------------
;
LOCK TABLE test.t1 WRITE;
#
echo
# ----- switch to connection con2 (user = test_user) -----
;
connection con2;
echo
# Send a statement to the server, but do not wait till the result
# comes back. We will pull this later.
;
send
SELECT COUNT(*) FROM test.t1;
echo
# ----- switch to connection default (user = root) -----
;
connection default;
echo
# Poll till INFO is no more NULL and State = 'Table Lock'.
;
let $wait_condition= SELECT COUNT(*) FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE INFO IS NOT NULL AND STATE = 'Table Lock';
--source include/wait_condition.inc
#
# Expect to see the state 'Table Lock' for the third connection because the SELECT
# collides with the WRITE TABLE LOCK.
--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME>
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
UNLOCK TABLES;
#
echo
# ----- switch to connection con2 (user = test_user) -----
;
connection con2;
echo
# Pull("reap") the result set from the statement executed with "send".
;
reap;
echo
# Ensure that SHOW/SELECT processlist can handle extreme long commands
#----------------------------------------------------------------------------
;
# We do not want to waste runtime, therefore we run the following test based
# on "Lock collision" and not with some "sleep(10)".
echo
# ----- switch to connection default (user = root) -----
;
connection default;
LOCK TABLE test.t1 WRITE;
#
echo
# ----- switch to connection con2 (user = test_user) -----
;
connection con2;
echo
# Send a long (~20 KB code) statement to the server, but do not wait
# till the result comes back. We will pull this later.
;
let $string=
`SELECT CONCAT('BEGIN-',
REPEAT('This is the representative of a very long statement.',400),
'-END')`;
let $my_statement =
SELECT count(*),'$string' AS "Long string" FROM test.t1;
send;
eval $my_statement;
echo
# ----- switch to connection default (user = root) -----
;
connection default;
echo
# Poll till INFO is no more NULL and State = 'Table Lock'.
;
let $wait_condition= SELECT COUNT(*) FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE INFO IS NOT NULL AND STATE = 'Waiting for table';
--source include/wait_condition.inc
echo
# Expect result:
# Statement Content of INFO
# SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST Complete statement
# SHOW FULL PROCESSLIST Complete statement
# SHOW PROCESSLIST statement truncated after 100 char
;
--replace_column 1 <ID> 3 <HOST_NAME> 5 <COMMAND> 6 <TIME> 7 <STATE>
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
--replace_column 1 <ID> 3 <HOST_NAME> 5 <COMMAND> 6 <TIME> 7 <STATE>
SHOW FULL PROCESSLIST;
--replace_column 1 <ID> 3 <HOST_NAME> 5 <COMMAND> 6 <TIME> 7 <STATE>
SHOW PROCESSLIST;
UNLOCK TABLES;
echo
# ----- switch to connection con2 (user = test_user) -----
;
connection con2;
echo
# Pull("reap") the result set from the monster statement executed with "send".
;
reap;
# Cleanup
echo
# ----- switch to connection default (user = root) -----
;
connection default;
echo
----- disconnect con1 and con2 -----
;
disconnect con1;
disconnect con2;
DROP USER test_user@'localhost';
DROP TABLE test.t1;