------------------------------------------------------------
revno: 3258
committer: Jon Olav Hauglid <jon.hauglid@oracle.com>
branch nick: mysql-trunk-bug12663165
timestamp: Thu 2011-07-14 10:05:12 +0200
message:
  Bug#12663165 SP DEAD CODE REMOVAL DOESN'T UNDERSTAND CONTINUE HANDLERS
  
  When stored routines are loaded, a simple optimizer tries to locate
  and remove dead code. The problem was that this dead code removal
  did not work correctly with CONTINUE handlers.
  
  If a statement triggers a CONTINUE handler, the following statement
  will be executed after the handler statement has completed. This
  means that the following statement is not dead code even if the
  previous statement unconditionally alters control flow. This fact
  was lost on the dead code removal routine, which ended up with
  removing instructions that could have been executed. This could
  then lead to assertions, crashes and generally bad behavior when
  the stored routine was executed.
  
  This patch fixes the problem by marking as live code all stored
  routine instructions that are in the same scope as a CONTINUE handler.
  
  Test case added to sp.test.

CREATE TABLE bug13510739 (c INTEGER NOT NULL, PRIMARY KEY (c)) ENGINE=INNODB;
INSERT INTO bug13510739 VALUES (1), (2), (3), (4);
DELETE FROM bug13510739 WHERE c=2;
HANDLER bug13510739 OPEN;
HANDLER bug13510739 READ `primary` = (2);
HANDLER bug13510739 READ `primary` NEXT;  <-- crash

The bug is that in the particular testcase row_search_for_mysql() picked up
a delete-marked record and quit, leaving the cursor non-positioned state and
on the subsequent 'get next' call the code crashed because of the
non-positioned cursor.

In row0sel.cc (line numbers from mysql-trunk):

4653         if (rec_get_deleted_flag(rec, comp)) {
...
4679                 if (index == clust_index && unique_search) {
4680 
4681                         err = DB_RECORD_NOT_FOUND;
4682                         
4683                         goto normal_return;
4684                 }       

it quit from here, not storing the cursor position.

In contrast, if the record=2 is not found at all (e.g. sleep(1) after DELETE
to let the purge wipe it away completely) then 'get = 2' does find record=3
and quits from here:

4366                 if (0 != cmp_dtuple_rec(search_tuple, rec, offsets)) {
...
4394                         btr_pcur_store_position(pcur, &mtr);
4395 
4396                         err = DB_RECORD_NOT_FOUND;
4397 #if 0
4398                         ut_print_name(stderr, trx, FALSE, index->name);
4399                         fputs(" record not found 3\n", stderr);
4400 #endif
4401 
4402                         goto normal_return;

Another fix could be to extend the condition on line 4366 to hold only if
seach_tuple matches rec AND if rec is not delete marked.

Notice that in the above test case if we wait about 1 second somewhere after
DELETE and before 'get = 2', then the testcase does not crash and returns 4
instead. Not sure if this is the correct behavior, but this bugfix removes
the crash and makes the code return what it also returns in the non-crashing
case (if rec=2 is not found during 'get = 2', e.g. we have sleep(1) there).

Approved by:	Marko (http://bur03.no.oracle.com/rb/r/863/)

The counter handler_read_key (SSV::ha_read_key_count) is incremented 
incorrectly.

The mysql server maintains a per thread system_status_var (SSV)
object.  This object contains among other things the counter
SSV::ha_read_key_count. The purpose of this counter is to measure the
number of requests to read a row based on a key (or the number of
index lookups).

This counter was wrongly incremented in the
ha_innobase::innobase_get_index(). The fix removes
this increment statement (for both innodb and innodb_plugin).

The various callers of the innobase_get_index() was checked to
determine if anybody must increment this counter (if they first call
innobase_get_index() and then perform an index lookup).  It was found
that no caller of innobase_get_index() needs to worry about the
SSV::ha_read_key_count counter.

SMALL KEY CACHE

The server crashed on division by zero because the key cache was not
initialized and the block length was 0 which was used in a division.

The fix was to not allow CACHE INDEX if the key cache was not initiallized.
Thus never try LOAD INDEX INTO CACHE for an uninitialized key cache.

Also added some windows files/directories to .bzrignore.

When printing information about a ROW_FORMAT=REDUNDANT record, pass
the correct flag to rec_get_next_offs().

rb:821 approved by Jimmy Yang

Post-push fix: build break on windows/optimized

handle_segfault is the signal handler code of mysqld.  however, it makes
calls to potentially unsafe functions localtime_r, fprintf, fflush.



include/my_stacktrace.h:
  Add safe versions of itoa() write() and snprintf().
libmysqld/CMakeLists.txt:
  Move signal handler to separate file.
mysys/stacktrace.c:
  Remove unsafe function calls.
sql/CMakeLists.txt:
  Move signal handler to separate file.
sql/Makefile.am:
  Move signal handler to separate file.
sql/mysqld.cc:
  Move signal handler to separate file.
sql/signal_handler.cc:
  Remove unsafe function calls.

readline.cc: In function char* batch_readline(LINE_BUFFER*):
readline.cc:60:9: error: out_length may be used uninitialized in this function
log.cc: In function int find_uniq_filename(char*):
log.cc:1857:8: error: number may be used uninitialized in this function

                    WITH MYISAM_USE_MMAP ENABLED

MySQL server can crash due to segmentation fault when
started with myisam_use_mmap.

The reason behind this being, while making a request to
unmap (munmap) the previously mapped memory (mmap), the
size passed was 7 bytes larger than the size requested at
the time of mapping. This can eventually unmap the adjacent
memory mapped block, belonging to some other memory-map pool.
Hence the subsequent call to mmap can map a region which was
still a valid memory mapped area.

Fixed by removing the extra 7-byte margin which was erroneously
added to the size, used for unmappping.


storage/myisam/mi_close.c:
  Bug#11756764 48726: MYSQLD KEEPS CRASHING WITH SIGSEGV
                      WITH MYISAM_USE_MMAP ENABLED
  
  Added a condition to call _mi_unmap_file() in case
  of compressed records. mi_munmap_file() is called
  otherwise.
storage/myisam/mi_packrec.c:
  Bug#11756764 48726: MYSQLD KEEPS CRASHING WITH SIGSEGV
                      WITH MYISAM_USE_MMAP ENABLED
  
  mi_dynmap_file() function, after successfully executing
  mmap, stores the total size in info->s->mapped_length
  variable. Now, if mi_dynmap_file() is invoked with a size
  with an extra 7-byte margin (MEMMAP_EXTRA_MARGIN),
  the margin will eventually also get stored in mapped_length.
  So, un-mapping function can simply use the value stored in
  mapped_length in order to unmap the previously mapped
  region.

                      AND HANG IN SHOW TABLE STATUS.

ISSUE: Table corruption due to concurrent queries.
       Different threads running insert and check
       query leads to table corruption. Not properly locked,
       rows are inserted in between check query.

SOLUTION: In check query mutex lock is acquired
          for a longer time to handle concurrent
          insert and check query.

NOTE: Additionally we backported the fix for CHECKSUM
      issue(bug#11758979).

sporadically on 5.1. See Bug#12584161.

Test runs successfully on 5.5/trunk, so this changeset will
be null-merged.

  
rb://816
approved by: Marko Makela
  
The title is misleading. This bug was actually introduced by
bug 12635227 and was unearthed by a later optimization.
We need to free buf_page_t structs that we are allocating using
malloc() at shutdown.

The bug was accidentally fixed by fixing
Bug#11759688 52020: InnoDB can still deadlock on just INSERT...ON DUPLICATE KEY
a.k.a. the reintroduction of
Bug#7975 deadlock without any locking, simple select and update

a.k.a. Bug#7975 deadlock without any locking, simple select and update

Bug#7975 was reintroduced when the storage engine API was made
pluggable in MySQL 5.1. Instead of looking at thd->lex directly, we
rely on handler::extra(). But, we were looking at the wrong extra()
flag, and we were ignoring the TRX_DUP_REPLACE flag in places where we
should obey it.

innodb_replace.test: Add tests for hopefully all affected statement
types, so that bug should never ever resurface. This kind of tests
should have been added when fixing Bug#7975 in MySQL 5.0.3 in the
first place.

rb:806 approved by Sunny Bains

btr_pcur_restore_position_func(): When the cursor was positioned at
the tree infimum or supremum, initialize pos_state and latch_mode. The
assertion failed, because pos_state was BTR_PCUR_WAS_POSITIONED.  In
the test failure of WL#5874, the purge thread attempted to restore the
cursor position on the infimum record (the clustered index was empty).

btr_pcur_detach(), btr_pcur_is_detached(): Unused functions, remove.

rb:804 approved by Inaam Rana

In all callers of row_sel_convert_mysql_key_to_innobase(), assert
that the converted key is empty or nonempty when it should be.

Also fixed possibly uninitialized use of need_copy_table_res.

row_rename_table_for_mysql(): Return DB_ERROR instead of DB_SUCCESS
when fil_rename_tablespace() returns an error. This bug was introduced
in the InnoDB Plugin.

Approved by Sunny Bains over IM.