Commit e508ad16 authored by monty@tik.mysql.fi's avatar monty@tik.mysql.fi

Fix for LOCK TABLES and BDB tables

parent 5b4d5d50
No related merge requests found
...@@ -5467,9 +5467,10 @@ something that is of course not true. We could make things even worse ...@@ -5467,9 +5467,10 @@ something that is of course not true. We could make things even worse
by just taking the test where PostgreSQL performs worst and claim that by just taking the test where PostgreSQL performs worst and claim that
MySQL is more than 2000 times faster than PostgreSQL. MySQL is more than 2000 times faster than PostgreSQL.
The case is that MySQL does a lot of optimizations that PostgreSQL doesn't The case is that MySQL does a lot of optimizations that PostgreSQL
do and the other way around. An SQL optimizer is a very complex thing, and doesn't do. This is of course also true the other way around. An SQL
a company could spend years on just making the optimizer faster and faster. optimizer is a very complex thing, and a company could spend years on
just making the optimizer faster and faster.
When looking at the benchmark results you should look for things that When looking at the benchmark results you should look for things that
you do in your application and just use these results to decide which you do in your application and just use these results to decide which
...@@ -5604,12 +5605,14 @@ MySQL with 2000 simultaneous connections doing 400 queries per second. ...@@ -5604,12 +5605,14 @@ MySQL with 2000 simultaneous connections doing 400 queries per second.
It sounded like he was using a Linux kernel that either had some It sounded like he was using a Linux kernel that either had some
problems with many threads, such as kernels before 2.4, which had a problem problems with many threads, such as kernels before 2.4, which had a problem
with this but we have documented how to fix this and Tim should be aware of with many threads on multi-CPU machines. We have documented in this manual
this problem. The other possible problem could have been an old glibc how to fix this and Tim should be aware of this problem.
library and that Tim didn't use a MySQL binary from our site, which is
linked with a corrected glibc library, but had compiled a version of his The other possible problem could have been an old glibc library and
own with. In any of the above cases, the symptom would have been exactly that Tim didn't use a MySQL binary from our site, which is linked with
what Tim had measured. a corrected glibc library, but had compiled a version of his own with.
In any of the above cases, the symptom would have been exactly what Tim
had measured.
We asked Tim if we could get access to his data so that we could repeat We asked Tim if we could get access to his data so that we could repeat
the benchmark and if he could check the MySQL version on the machine to the benchmark and if he could check the MySQL version on the machine to
...@@ -5618,6 +5621,16 @@ He has not done that yet. ...@@ -5618,6 +5621,16 @@ He has not done that yet.
Because of this we can't put any trust in this benchmark either :( Because of this we can't put any trust in this benchmark either :(
Over time things also changes and the above benchmarks are not that
relevant anymore. MySQL now have a couple of different table handlers
with different speed/concurrency tradeoffs. @xref{Table types}. It
would be interesting to see how the above tests would run with the
different transactional table types in MySQL. PostgreSQL has of course
also got new features since the test was made. As the above test are
not publicly available there is no way for us to know how the
database would preform in the same tests today.
Conclusion: Conclusion:
The only benchmarks that exist today that anyone can download and run The only benchmarks that exist today that anyone can download and run
...@@ -5632,15 +5645,15 @@ The thing we find strange is that every test we have seen about ...@@ -5632,15 +5645,15 @@ The thing we find strange is that every test we have seen about
PostgreSQL, that is impossible to reproduce, claims that PostgreSQL is PostgreSQL, that is impossible to reproduce, claims that PostgreSQL is
better in most cases while our tests, which anyone can reproduce, better in most cases while our tests, which anyone can reproduce,
clearly shows otherwise. With this we don't want to say that PostgreSQL clearly shows otherwise. With this we don't want to say that PostgreSQL
isn't good at many things (it is!). We would just like to see a fair test isn't good at many things (it is!) or that it isn't faster than MySQL
where they are very good so that we could get some friendly competition under certain conditions. We would just like to see a fair test where
going! they are very good so that we could get some friendly competition going!
For more information about our benchmarks suite @xref{MySQL Benchmarks}. For more information about our benchmarks suite @xref{MySQL Benchmarks}.
We are working on an even better benchmark suite, including much better We are working on an even better benchmark suite, including multi user
documentation of what the individual tests really do, and how to add more tests, and a better documentation of what the individual tests really
tests to the suite. do and how to add more tests to the suite.
@node TODO, , Comparisons, Introduction @node TODO, , Comparisons, Introduction
...@@ -46771,7 +46784,7 @@ not yet 100% confident in this code. ...@@ -46771,7 +46784,7 @@ not yet 100% confident in this code.
@appendixsubsec Changes in release 3.23.42 @appendixsubsec Changes in release 3.23.42
@itemize @bullet @itemize @bullet
@item @item
Fixed a problem when using @code{LOCK TABLES} and @code{BDB} tables. Fixed problem when using @code{LOCK TABLES} and @code{BDB} tables.
@item @item
Fixed problem with @code{REPAIR TABLE} on MyISAM tables with row lengths Fixed problem with @code{REPAIR TABLE} on MyISAM tables with row lengths
between 65517 - 65520 bytes between 65517 - 65520 bytes
...@@ -1658,12 +1658,15 @@ int ha_berkeley::external_lock(THD *thd, int lock_type) ...@@ -1658,12 +1658,15 @@ int ha_berkeley::external_lock(THD *thd, int lock_type)
{ {
if (!thd->transaction.bdb_lock_count++) if (!thd->transaction.bdb_lock_count++)
{ {
changed_rows=0;
/* First table lock, start transaction */ /* First table lock, start transaction */
if ((thd->options & (OPTION_NOT_AUTO_COMMIT | OPTION_BEGIN)) && if ((thd->options & (OPTION_NOT_AUTO_COMMIT | OPTION_BEGIN |
OPTION_TABLE_LOCK)) &&
!thd->transaction.all.bdb_tid) !thd->transaction.all.bdb_tid)
{ {
DBUG_ASSERT(thd->transaction.stmt.bdb_tid != 0);
/* We have to start a master transaction */ /* We have to start a master transaction */
DBUG_PRINT("trans",("starting transaction")); DBUG_PRINT("trans",("starting transaction all"));
if ((error=txn_begin(db_env, 0, if ((error=txn_begin(db_env, 0,
(DB_TXN**) &thd->transaction.all.bdb_tid, (DB_TXN**) &thd->transaction.all.bdb_tid,
0))) 0)))
...@@ -1671,8 +1674,10 @@ int ha_berkeley::external_lock(THD *thd, int lock_type) ...@@ -1671,8 +1674,10 @@ int ha_berkeley::external_lock(THD *thd, int lock_type)
thd->transaction.bdb_lock_count--; // We didn't get the lock /* purecov: inspected */ thd->transaction.bdb_lock_count--; // We didn't get the lock /* purecov: inspected */
DBUG_RETURN(error); /* purecov: inspected */ DBUG_RETURN(error); /* purecov: inspected */
} }
if (thd->in_lock_tables)
DBUG_RETURN(0); // Don't create stmt trans
} }
DBUG_PRINT("trans",("starting transaction for statement")); DBUG_PRINT("trans",("starting transaction stmt"));
if ((error=txn_begin(db_env, if ((error=txn_begin(db_env,
(DB_TXN*) thd->transaction.all.bdb_tid, (DB_TXN*) thd->transaction.all.bdb_tid,
(DB_TXN**) &thd->transaction.stmt.bdb_tid, (DB_TXN**) &thd->transaction.stmt.bdb_tid,
...@@ -1684,7 +1689,6 @@ int ha_berkeley::external_lock(THD *thd, int lock_type) ...@@ -1684,7 +1689,6 @@ int ha_berkeley::external_lock(THD *thd, int lock_type)
} }
} }
transaction= (DB_TXN*) thd->transaction.stmt.bdb_tid; transaction= (DB_TXN*) thd->transaction.stmt.bdb_tid;
changed_rows=0;
} }
else else
{ {
...@@ -1722,6 +1726,7 @@ int ha_berkeley::start_stmt(THD *thd) ...@@ -1722,6 +1726,7 @@ int ha_berkeley::start_stmt(THD *thd)
DBUG_ENTER("ha_berkeley::start_stmt"); DBUG_ENTER("ha_berkeley::start_stmt");
if (!thd->transaction.stmt.bdb_tid) if (!thd->transaction.stmt.bdb_tid)
{ {
DBUG_PRINT("trans",("starting transaction stmt"));
error=txn_begin(db_env, (DB_TXN*) thd->transaction.all.bdb_tid, error=txn_begin(db_env, (DB_TXN*) thd->transaction.all.bdb_tid,
(DB_TXN**) &thd->transaction.stmt.bdb_tid, (DB_TXN**) &thd->transaction.stmt.bdb_tid,
0); 0);
......
...@@ -163,7 +163,8 @@ void kill_one_thread(THD *thd, ulong id); ...@@ -163,7 +163,8 @@ void kill_one_thread(THD *thd, ulong id);
#define OPTION_BIN_LOG OPTION_BUFFER_RESULT*2 #define OPTION_BIN_LOG OPTION_BUFFER_RESULT*2
#define OPTION_NOT_AUTO_COMMIT OPTION_BIN_LOG*2 #define OPTION_NOT_AUTO_COMMIT OPTION_BIN_LOG*2
#define OPTION_BEGIN OPTION_NOT_AUTO_COMMIT*2 #define OPTION_BEGIN OPTION_NOT_AUTO_COMMIT*2
#define OPTION_QUICK OPTION_BEGIN*2 #define OPTION_TABLE_LOCK OPTION_BEGIN*2
#define OPTION_QUICK OPTION_TABLE_LOCK*2
#define OPTION_QUOTE_SHOW_CREATE OPTION_QUICK*2 #define OPTION_QUOTE_SHOW_CREATE OPTION_QUICK*2
#define OPTION_INTERNAL_SUBTRANSACTIONS OPTION_QUOTE_SHOW_CREATE*2 #define OPTION_INTERNAL_SUBTRANSACTIONS OPTION_QUOTE_SHOW_CREATE*2
......
...@@ -81,7 +81,8 @@ static void init_signals(void) ...@@ -81,7 +81,8 @@ static void init_signals(void)
inline bool end_active_trans(THD *thd) inline bool end_active_trans(THD *thd)
{ {
int error=0; int error=0;
if (thd->options & (OPTION_NOT_AUTO_COMMIT | OPTION_BEGIN)) if (thd->options & (OPTION_NOT_AUTO_COMMIT | OPTION_BEGIN |
OPTION_TABLE_LOCK))
{ {
thd->options&= ~(ulong) (OPTION_BEGIN | OPTION_STATUS_NO_TRANS_UPDATE); thd->options&= ~(ulong) (OPTION_BEGIN | OPTION_STATUS_NO_TRANS_UPDATE);
thd->server_status&= ~SERVER_STATUS_IN_TRANS; thd->server_status&= ~SERVER_STATUS_IN_TRANS;
...@@ -1825,7 +1826,11 @@ mysql_execute_command(void) ...@@ -1825,7 +1826,11 @@ mysql_execute_command(void)
{ {
thd->lock=thd->locked_tables; thd->lock=thd->locked_tables;
thd->locked_tables=0; // Will be automaticly closed thd->locked_tables=0; // Will be automaticly closed
}
if (thd->options & OPTION_TABLE_LOCK)
{
end_active_trans(thd); end_active_trans(thd);
thd->options&= ~(ulong) (OPTION_TABLE_LOCK);
} }
if (thd->global_read_lock) if (thd->global_read_lock)
{ {
...@@ -1847,12 +1852,15 @@ mysql_execute_command(void) ...@@ -1847,12 +1852,15 @@ mysql_execute_command(void)
if (check_db_used(thd,tables) || end_active_trans(thd)) if (check_db_used(thd,tables) || end_active_trans(thd))
goto error; goto error;
thd->in_lock_tables=1; thd->in_lock_tables=1;
thd->options|= OPTION_TABLE_LOCK;
if (!(res=open_and_lock_tables(thd,tables))) if (!(res=open_and_lock_tables(thd,tables)))
{ {
thd->locked_tables=thd->lock; thd->locked_tables=thd->lock;
thd->lock=0; thd->lock=0;
send_ok(&thd->net); send_ok(&thd->net);
} }
else
thd->options&= ~(ulong) (OPTION_TABLE_LOCK);
thd->in_lock_tables=0; thd->in_lock_tables=0;
break; break;
case SQLCOM_CREATE_DB: case SQLCOM_CREATE_DB:
......
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