Commit 76eaa259 authored by unknown's avatar unknown

fixed mysterious offset confusion bug

added a test case for it - took some creative work to figure out
how to make it happen at will
updated the manual


Docs/manual.texi:
  fixed wrong info on SLAVE_SKIP_COUNTER
  fixed wrong info in BitKeeper tree build instructions
  updated change history about bug fix
mysql-test/t/rpl_sporadic_master.test:
  tried hard to get slave confused, but failed. nevertheless, a more
  exhaustive test case does not hurt
sql/slave.cc:
  fixed mysterious offset confusion bug
parent 2cbf3b9b
......@@ -6543,8 +6543,8 @@ shell> make
A collection of our standard configure scripts is located in the
@file{BUILD/} subdirectory. If you are lazy, you can use
@file{BUILD/compile-pentium-debug}. It will actually work on a lot of
non-x86 machines despite its name.
@file{BUILD/compile-pentium-debug}. To compile on a different architecture,
modify the script removing flags that are Pentium-specific.
@item
When the build is done, run @code{make install}. Be careful with this
......@@ -29828,8 +29828,11 @@ query from the master.
@item
If you have decided you can skip the next query, do
@code{SET SQL_SLAVE_SKIP_COUNTER=1; SLAVE START;} to skip a query that
does not use auto_increment, last_insert_id or timestamp, or
@code{SET SQL_SLAVE_SKIP_COUNTER=2; SLAVE START;} otherwise
does not use auto_increment, or last_insert_id or
@code{SET SQL_SLAVE_SKIP_COUNTER=2; SLAVE START;} otherwise. The reason
auto_increment/last_insert_id queries are different is that they take
two events in the binary log of the master.
@item
If you are sure the slave started out perfectly in sync with the master,
and no one has updated the tables involved outside of slave thread,
......@@ -45728,6 +45731,9 @@ not yet 100% confident in this code.
@appendixsubsec Changes in release 3.23.40
@itemize @bullet
@item
Fixed bug in slave thread when under some rare circumstances it could
get 22 bytes ahead on the offset in the master
@item
Added @code{slave_wait_timeout} for replication.
@item
Fixed problem with @code{UPDATE} and BDB tables.
n
1
2
3
# test case to make slave thread get ahead by 22 bytes
source include/master-slave.inc;
connection master;
# first, cause a duplicate key problem on the slave
create table t1(n int auto_increment primary key);
save_master_pos;
connection slave;
sync_with_master;
insert into t1 values (2);
connection master;
insert into t1 values(NULL);
insert into t1 values(NULL);
save_master_pos;
connection slave;
sleep 1; # there is no way around this sleep - we have to wait until
# the slave tries to run the query, fails and aborts slave thread
delete from t1 where n = 2;
slave start;
sync_with_master;
#now the buggy slave would be confused on the offset but it can replicate
#in order to make it break, we need to stop/start the slave one more time
slave stop;
connection master;
# to be able to really confuse the slave, we need some non-auto-increment
# events in the log
create table t2(n int);
drop table t2;
insert into t1 values(NULL);
save_master_pos;
connection slave;
slave start;
#now the truth comes out - if the slave is buggy, it will never sync because
#the slave thread is not able to read events
sync_with_master;
select * from t1;
#clean up
connection master;
drop table t1;
save_master_pos;
connection slave;
sync_with_master;
......@@ -3,12 +3,19 @@
source include/master-slave.inc;
connection master;
drop table if exists t1;
drop table if exists t1,t2;
create table t2(n int);
create table t1(n int not null auto_increment primary key);
insert into t1 values (NULL),(NULL);
delete from t1;
# We have to use 4 in the following to make this test work with all table types
insert into t1 values (4),(NULL);
save_master_pos;
connection slave;
sync_with_master;
slave stop;
slave start;
connection master;
insert into t1 values (NULL),(NULL);
flush logs;
delete from t1;
......@@ -20,7 +27,7 @@ connection slave;
sync_with_master;
select * from t1;
connection master;
drop table t1;
drop table t1,t2;
save_master_pos;
connection slave;
sync_with_master;
......@@ -1222,6 +1222,8 @@ pthread_handler_decl(handle_slave,arg __attribute__((unused)))
thd->thread_stack = (char*)&thd; // remember where our stack is
thd->temporary_tables = save_temporary_tables; // restore temp tables
threads.append(thd);
glob_mi.pending = 0; //this should always be set to 0 when the slave thread
// is started
DBUG_PRINT("info",("master info: log_file_name=%s, position=%s",
glob_mi.log_file_name, llstr(glob_mi.pos,llbuff)));
......
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