This function was introduced in r2606, when merging r2603 from branches/5.1.

Merge 2537:2605 from branches/5.1:

  ------------------------------------------------------------------------
  r2545 | vasil | 2008-07-25 17:24:23 +0300 (Fri, 25 Jul 2008) | 37 lines
  Changed paths:
     M /branches/5.1/handler/ha_innodb.cc
  
  branches/5.1:
  
  Fix Bug#38185 ha_innobase::info can hold locks even when called with HA_STATUS_NO_LOCK
  
  The fix is to call fsp_get_available_space_in_free_extents() from
  ha_innobase::info() only if HA_STATUS_NO_LOCK is not present in the flag
  *AND*
  change get_schema_tables_record() in MySQL's sql/sql_show.cc to call
  ::info() *without* HA_STATUS_NO_LOCK whenever a user issues SELECT FROM
  information_schema.tables;
  
  Without the change to sql/sql_show.cc this patch would lead to Bug#32440
  resurfacing. I.e. delete_length would never be updated in ::info() and
  will remain 0 forever, resulting in the free space not being shown
  anywhere.
  
  This is the change to sql/sql_show.cc for reference, it needs to be
  committed to the MySQL repo before or at the same time with this change
  to ha_innodb.cc:
  
   --- patch begins here ---
   --- sql/sql_show.cc.orig	2008-07-23 09:32:14.000000000 +0300
   +++ sql/sql_show.cc	2008-07-23 09:32:19.000000000 +0300
   @@ -3549,8 +3549,7 @@ static int get_schema_tables_record(THD 
    
        if(file)
        {
   -      file->info(HA_STATUS_VARIABLE | HA_STATUS_TIME | HA_STATUS_AUTO |
   -                 HA_STATUS_NO_LOCK);
   +      file->info(HA_STATUS_VARIABLE | HA_STATUS_TIME | HA_STATUS_AUTO);
          enum row_type row_type = file->get_row_type();
          switch (row_type) {
          case ROW_TYPE_NOT_USED:
   --- patch ends here ---
  
  Approved by:	Heikki
  
  ------------------------------------------------------------------------
  r2603 | marko | 2008-08-21 16:25:05 +0300 (Thu, 21 Aug 2008) | 10 lines
  Changed paths:
     M /branches/5.1/handler/ha_innodb.cc
     M /branches/5.1/include/ha_prototypes.h
     M /branches/5.1/row/row0sel.c
  
  branches/5.1: Identify SELECT statements by thd_sql_command() == SQLCOM_SELECT
  instead of parsing the query string.  This fixes MySQL Bug #37885 without
  us having to implement lexical analysis of SQL comments in yet another place.
  
  thd_is_select(): A new predicate.
  
  row_search_for_mysql(): Use thd_is_select().
  
  Approved by Heikki.
  
  ------------------------------------------------------------------------

dict_table_get_referenced_constraint(), dict_table_get_foreign_constraint():
Simplify the iteration loop.

dict_table_find_equivalent_index(): Correct the function comment.

cache, especially buf_pool->LRU_old and bpage->old.

buf_LRU_old_adjust_len(), buf_LRU_remove_block(): Check that blocks in
buf_pool->LRU_old have the "old" flag set and the blocks preceding
buf_pool->LRU_old have the "old" flag clear.

buf_LRU_add_block_low(), buf_relocate(): Check that buf_pool->LRU_old
is the first block in the LRU list whose "old" flag is set.

buf_LRU_free_block(): When replacing a control block in the LRU list
with a control block for a compressed page, assert that the "old"
flags in the neighboring LRU list entries grow monotonically.

buf_page_set_old(): Assert that the "old" flags in the neighboring LRU
list entries grow monotonically.

Adjust the callers where necessary:
buf_LRU_add_block_to_end_low() and buf_LRU_add_block_low().

file list link is written or read below FIL_PAGE_DATA.  This has
helped diagnose issue#63.

buf_pool->LRU_old_len.  However, we forgot to check if buf_pool->LRU_old
happens to point to b's successor in the LRU list.  If it does, we must
assign buf_pool->LRU_old = b.  The following invariants hold:

In the LRU list, the "old" flag should grow monotonically, i.e., it is 0
for the first few items and 1 from thereafter.

If buf_pool->LRU_old != NULL, it must point to the first item with old=1
in the LRU list, and there must be buf_pool->LRU_old_len old items in the list.

This should fix Mantis issue#50 and issue#68.

The cardinality of every index (the number of different key values) is
calculated when the table is opened, at SHOW TABLE STATUS,
ANALYZE TABLE and on other circumstances (like when the table has
changed too much). Note that if the mysql client is running with the
auto-rehash setting turned on (default) this causes all tables to be
opened when it starts.

Previously InnoDB sampled 8 random pages from the index to get an
estimate of the cardinality. Now the number of sampled pages can be
changed via the global parameter innodb_stats_sample_pages which can
be tuned at runtime. The default value for this parameter is 8.

If the value of this parameter is changed, there may be serious problems:

- small values (say, 1) can cause an error in table stats;
- values much larger than 8 (say, 100), can cause a big slowdown in
  table opening time, SHOW TABLE status, etc.
- query plans may be different from the old ones.

Approved by:	Heikki

Fix Mantis issue#66.

Do not try to dereference the MySQL thread object if it is NULL.

Approved by:	Sunny (via IM)

replace rbmode and "rollback mode"
with rb_ctx and "rollback context".
Suggested by Sunny.

recovery, tolerate clustered index records whose externally stored
columns have not been written.  This should remove the assertion failures
that were reported as Mantis issue#58, issue#62, issue#64.

trx_is_recv(): New function: TRUE if this transaction is rolling back
an incomplete transaction in crash recovery.

enum trx_rbmode: Rollback modes: no rollback, normal rollback, crash recovery.

btr_cur_pessimistic_delete(), btr_free_externally_stored_field(),
btr_rec_free_externally_stored_fields():
Replace the ibool parameter with enum trx_rbmode.

btr_free_externally_stored_field(): If field_ref is zero, return
but assert ut_a(rbmode == RB_RECOVERY).  Unless InnoDB has crashed
while inserting a clustered index record, field_ref should not be zero.

btr_rec_free_updated_extern_fields(): Add the parameter enum trx_rbmode.

btr_cur_pessimistic_update(): Pass the rbmode parameter to
btr_rec_free_updated_extern_fields().

row_undo_ins(), row_undo_mod_upd_del_sec(): If row_build_index_entry()
fails, assert trx_is_recv() and skip this secondary index.

row_undo_mod_upd_del_sec(): Empty the heap at the end of each loop
iteration in order to conserve memory and to reduce the number of
low-level memory allocations.

buf_flush_init_for_writing(), buf_LRU_block_remove_hashed_page():
Dump the page frame featuring the incorrect FIL_PAGE_TYPE along with the
page_zip->data that might contain an earlier version of the page.

buf_block_align() on a non-file page frame that was created in
btr_cur_pessimistic_insert(), to see if a record fits on a compressed
page by itself.  These assertions caused an assertion failure in
buf_block_align() in innodb_bug36172.test.

page_zip_write_rec(), page_zip_write_header(): Remove the assertion
that calls buf_frame_get_page_zip().

mem_heap_create_block(): Compute len and call mem_area_alloc() only once.

mem_heap_block_free(): Call mem_area_free() only once.

Approved by Heikki.

an incorrect value.  This is to track down Mantis issue#63 and issue#65.

buf_LRU_block_remove_hashed_page(),
buf_flush_init_for_writing(): dump the compressed page before ut_error.

added in r2554.  When this function is called on an empty new_block, "ret"
will always point to the page infimum.

ut_a(ret_pos > 0) that was added to page_copy_rec_list_end() in r2552,
as suggested by Sunny in Mantis issue#52.

Fix typo in comment.

that was suggested by Sunny in Mantis issue#52.

Fix typo in comment.

Fixes a race in recovery where the recovery thread recovering a
PREPARED trx and the background rollback thread can both try
to free the trx after its status is set to COMMITTED_IN_MEMORY.

trx->is_recovered flag was introduced in r2040.

Reviewed by: Sunny

This fix makes two basic changes in blob handling:
(The bug was introduced in r2252)

1) The blob prefixes are no longer stored in the undo if
  a) We are modifying a delete marked record and
  b) The record was delete marked by an already committed trx.

2) When building old row version to check if one of these versions
can hold an implicit lock on the record we stop our probe if
  a) The version is delete marked and
  b) The delete marking is done by a trx which is different from
     the current active trx on the record.

Reviewed by: Heikki

explicit BEGIN.

Fixed a mistake in r2539 where I changed UNIV_INLINE to UNIV_INTERN
for the wrong function in btr0sea.h

  ------------------------------------------------------------------------
  r2537 | inaam | 2008-07-15 20:46:03 +0300 (Tue, 15 Jul 2008) | 12 lines
  
  branches/5.1   issue# 4
  
  Fixed a timing hole where a thread dropping an index can free the
  in-memory index struct while another thread is still using
  that structure to remove entries from adaptive hash index belonging
  to one of the pages that belongs to the index being dropped.
  
  The fix is to have a reference counter in the index struct and to
  wait for this counter to drop to zero beforing freeing the struct.
  
  Reviewed by: Heikki
  
  ------------------------------------------------------------------------

Fix the failing innodb-index test by adjusting the result to a new
MySQL behavior. The author of the behavioral change
Davi Arnaut <davi@mysql.com>, BZR-r2667:
http://bazaar.launchpad.net/~mysql/mysql-server/mysql-5.1/revision/davi%40mysql.com-20080617141221-8yre8ys9j4uw3xx5?start_revid=joerg%40mysql.com-20080630105418-7qoe5ehomgrcdb89
has been asked if this change is intended:
http://lists.mysql.com/internals/35805

Regardless of the answer we need to adjust to the new behavior to get
the test to succeed. If they switch back, then we will revert this commit.

Add a space in a warning message. No functional change to the code.
The original message is "invalid innodb_file_format_checkvalue;...".
The new one is "invalid innodb_file_format_check value;..."

Fixes issue# 51 - by removing the negative test cases that produce
warnings. The warnings cause mysql-test-run to fail.

Those negative test cases will be moved to separate test/result files.

Approved by:    Sunny

Disable part of innodb-index test because MySQL changed its behavior and
is not calling ::add_index() anymore in the following ALTER TABLE:

CREATE TABLE t (a INT) ENGINE=INNODB;
INSERT INTO t VALUES (NULL);
ALTER TABLE t ADD PRIMARY KEY (a);  -- adding primary index on non-NULL column

Previously, in ALTER TABLE, MySQL would call ::add_index() which would
fail with a "primary key cannot contain NULL" error.

The change occured in:

  mysql-5.1$ bzr log -v -r2667
  ------------------------------------------------------------
  revno: 2667
  committer: Davi Arnaut <davi@mysql.com>
  branch nick: 33873-5.1
  timestamp: Tue 2008-06-17 11:12:21 -0300
  message:
    Bug#33873: Fast ALTER TABLE doesn't work with multibyte character sets
    
    The problem was that when comparing tables for a possible
    fast alter table, the comparison was being performed using
    the parsed information and not the final definition.
          
    The solution is to use the possible final table layout to
    compare if a fast alter is possible or not.
  modified:
    mysql-test/include/mix1.inc
    mysql-test/r/alter_table.result
    mysql-test/r/innodb_mysql.result
    mysql-test/t/alter_table.test
    sql/sql_table.cc
  mysql-5.1$

  ------------------------------------------------------------------------
  r2519 | sunny | 2008-06-26 16:55:43 +0300 (Thu, 26 Jun 2008) | 5 lines
  
  branches/5.1: Add test cases and fix a bug where the last AUTOINC cached value
  was not reset to 0 when the table was truncated.
  
  Bug #37531 : After truncate, auto_increment behaves incorrectly for InnoDB
  
  ------------------------------------------------------------------------
  r2520 | vasil | 2008-06-26 17:38:02 +0300 (Thu, 26 Jun 2008) | 7 lines
  
  branches/5.1:
   
  Fix Bug#36941 Performance problem in ha_print_info (SHOW INNODB STATUS)
  by disabling some of the code in ha_print_info() in production builds.
   
  Approved by:	Heikki (via IM)
  
  ------------------------------------------------------------------------
  r2521 | vasil | 2008-06-26 17:39:01 +0300 (Thu, 26 Jun 2008) | 8 lines
  
  branches/5.1:
   
  Fix Bug#36942 Performance problem in lock_get_n_rec_locks (SHOW INNODB STATUS)
  by not calling lock_get_n_rec_locks() from lock_print_info_summary() on
  production builds.
   
  Approved by:	Heikki (via IM)
  
  ------------------------------------------------------------------------
  r2524 | vasil | 2008-07-01 10:37:34 +0300 (Tue, 01 Jul 2008) | 29 lines
  
  branches/5.1:
  
  Merge a change from MySQL (this fixes the failing innodb-replace test):
  
    revno: 2659
    committer: Mattias Jonsson <mattiasj@mysql.com>
    branch nick: b31210-51-bugteam
    timestamp: Tue 2008-06-03 13:25:41 +0200
    message:
      Bug#31210: INSERT DELAYED crashes server when used on partitioned tables
        
      Problem was an unclear error message since it could suggest that
      MyISAM did not support INSERT DELAYED.
      Changed the error message to say that DELAYED is not supported by the
      table, instead of the table's storage engine.
      The confusion is that a partitioned table is in somewhat sense using
      the partitioning storage engine, which in turn uses the ordinary
      storage engine. By saying that the table does not support DELAYED we
      do not give any extra informantion about the storage engine or if it
      is partitioned.
    modified:
      mysql-test/r/innodb-replace.result
      mysql-test/t/innodb-replace.test
      mysql-test/t/merge.test
      mysql-test/t/partition_hash.test
      sql/share/errmsg.txt
      sql/sql_insert.cc


------------------------------------------------------------------------

 
Rewrite the function innodb_plugin_init() to support parameters in
different order (in static and dynamic InnoDB) and to support more
parameters in the static InnoDB.
 
The previous implementation traversed both lists at the same time,
skipping parameters in the dynamic list that do not exist in the static
list. E.g. both lists were allowed to be static=(a, b, c),
dynamic=(a, b, c) or static=(a, b, c), dynamic=(a, b, x, c).
 
With the new implementation they are allowed to be
static=(a, b, c), dynamic=(b, a, c) or
static=(a, b, x, c), dynamic=(b, a, c) in addition.

The new implementation has complexity O(N^2) while the old one was O(N),
but this is acceptable sacrifice provided that innodb_plugin_init() is
called once per InnoDB lifetime and that N=39 currently, and N is not
going to increase much in the future, N=number of the InnoDB parameters.

Suggested by:	Sunny
Approved by:	Sunny

Fix the rpl_ddl mysql-test that produces a warnings:

  master.err: rpl.rpl_ddl: 080611 16:27:01 [Warning] MySQL is closing a connection that has an active InnoDB transaction.  13 row modifications will roll back.

the bug was introduced in r2256, which adds "prebuilt->trx->active_trans = 1;"
in ::add_index() and ::final_drop_index() but never calls innobase_commit() or
innobase_rollback() to set back active_trans to 0.

Also, per Heikki's suggestion we remove the calls to trans_register_ha() from
::add_index() and ::final_drop_index(). Following is the IM discussion that
took place about this:

  --- cut ---
  (17:59:05) vasil: 
          unsigned        active_trans:2; /* 1 - if a transaction in MySQL
                                          is active. 2 - if prepare_commit_mutex
                                          was taken */
  
  (17:59:13) vasil: what about 0?
  (17:59:26) Heikki: Hmm
  (17:59:42) Heikki: Maybe in the other cases :)
  (18:01:00) vasil: 
     2   1369  handler/ha_innodb.cc <<<unknown>>>
               if (trx->active_trans == 0) {
     3   1372  handler/ha_innodb.cc <<<unknown>>>
               trx->active_trans = 1;
  
  (18:01:05) vasil: yes, it can be 0
  (18:01:38) Heikki: Maybe no active transaction => the value is 0
  (18:02:03) vasil: probably yes
  (18:09:09) vasil: 
          /* The flag trx->active_trans is set to 1 in
  
          1. ::external_lock(),
          2. ::start_stmt(),
          3. innobase_query_caching_of_table_permitted(),
          4. innobase_savepoint(),
          5. ::init_table_handle_for_HANDLER(),
          6. innobase_start_trx_and_assign_read_view(),
          7. ::transactional_table_lock()
  
          and it is only set to 0 in a commit or a rollback.
  (18:09:14) vasil: this is no longer true
  (18:09:35) vasil: it is also set to 1 in ::final_drop_index
  (18:09:56) vasil: and in ::add_index()
  (18:12:31) Heikki: Please correct the comment :(
  (18:13:01) vasil: it is not only the comment, I am trying to understand what's wrong
  (18:13:28) Heikki: What is the symptom?
  (18:14:37) vasil: can you find this email and the subsequent one:
  
  From: Vasil Dimov <vasil.dimov@oracle.com>
  To: InnoDB Dev <innodb_dev_ww@oracle.com>
  Subject: Re: innodb - marko - r2256 - in branches/zip: handler include lock
          trx
  Date: Wed, 11 Jun 2008 16:33:47 +0300
  
  (18:15:02) vasil: the symptom is 
  
  master.err: rpl.rpl_ddl: 080611 16:27:01 [Warning] MySQL is closing a connection that has
  +an active InnoDB transaction.  13 row modifications will roll back.
  
  (18:16:22) vasil: My understanding till now is that active_trans is set to 1 in ::add_index() and forgotten like this, never set to 0; I wonder if it should be set to 0 somewhere at the end or not set to 1 at all... or there is more...
  (18:16:31) Heikki: Vasil, ok the problem is that Marko forgets to commit the transaction
  (18:16:55) Heikki: An active transaction has to be committed or rolled back
  (18:17:09) vasil: but i can find this in ::add_index():
  
          /* Commit the data dictionary transaction in order to release
          the table locks on the system tables.  Unfortunately, this
          means that if MySQL crashes while creating a new primary key
          inside row_merge_build_indexes(), indexed_table will not be
          dropped on crash recovery.  Thus, it will become orphaned. */
          trx_commit_for_mysql(trx);
  
  (18:17:27) vasil: but this function does not set active_trans to 0
  (18:17:43) Heikki: Let me look
  (18:19:20) vasil: it is only set to 0 in innobase_commit() and in innobase_rollback()
  (18:20:10) Heikki: Ok
  (18:20:59) Heikki: Hmm...
  (18:21:08) vasil: innobase_commit() calls innobase_commit_low() calls trx_commit_for_mysql()
  innobase_commit() sets active_trans=0
  (18:21:26) Heikki: active_trans is strictly a ha_innodb.cc variable
  (18:21:53) Heikki: It is intended to be used in transactions visible to MySQL
  (18:22:25) Heikki: I think Marko should call innobase_commit()
  (18:23:51) vasil: but still set active_trans=1 inside :add_index() inside handler/handler0alter.cc?
  (18:24:12) Heikki: Hmm
  (18:24:56) Heikki: I think the transaction is NOT really visible to MySQL
  (18:24:57) vasil: 
  > Author: marko
  > Date: 2008-01-25 16:26:07 +0200 (Fri, 25 Jan 2008)
  > New Revision: 2256
  >
  > Log:
  > branches/zip: Fast index creation: Release locks on system tables before
  > creating indexes.  Lock the user table inside the user transaction.
  >
  > enum trx_dict_op: Remove TRX_OP_INDEX_MAY_WAIT.
  >
  > ha_innobase::add_index(): Lock the user tables within prebuilt->trx.
  > Commit the data dictionary transaction before creating indexes.
  >
  > ha_innobase::final_drop_index(): Lock the user table within prebuilt->trx.
  
  (18:26:41) Heikki: Let me look at the old ::create_table()
  (18:27:25) Heikki: Ok, in the old code, the transactions are internal to InnoDB, not visible to MySQL
  (18:27:46) Heikki: I think it is an error to set active_trans=1 inside :add_index() i
  (18:28:11) Heikki: MySQL is not really interested in HOW the engine adds the index. In a transaction or not.
  (18:28:26) vasil: this is the change inside drop_index(), that is supposed to "Lock the user table within prebuilt->trx":
  (18:28:37) vasil: 
  @@ -1093,27 +1101,25 @@ ha_innobase::final_drop_index(
    /* Create a background transaction for the operations on
    the data dictionary tables. */
    trx = trx_allocate_for_mysql();
    trx_start_if_not_started(trx);
   
    trans_register_ha(user_thd, FALSE, ht);
  + prebuilt->trx->active_trans = 1;
   
    trx->mysql_thd = user_thd;
    trx->mysql_query_str = thd_query(user_thd);
   
    /* Flag this transaction as a dictionary operation, so that
  - the data dictionary will be locked in crash recovery.  Prevent
  - warnings if row_merge_lock_table() results in a lock wait,
  - i.e., when another transaction is holding a conflicting lock
  - on the table, e.g., because of SELECT ... FOR UPDATE. */
  - trx_set_dict_operation(trx, TRX_DICT_OP_INDEX_MAY_WAIT);
  + the data dictionary will be locked in crash recovery. */
  + trx_set_dict_operation(trx, TRX_DICT_OP_INDEX);
   
    /* Lock the table exclusively, to ensure that no active
    transaction depends on an index that is being dropped. */
    err = convert_error_code_to_mysql(
  -  row_merge_lock_table(trx, prebuilt->table, LOCK_X),
  +  row_merge_lock_table(prebuilt->trx, prebuilt->table, LOCK_X),
     user_thd);
   
    if (UNIV_UNLIKELY(err)) {
   
     /* Unmark the indexes to be dropped. */
     row_mysql_lock_data_dictionary(trx);
  @@ -1125,14 +1131,12 @@ ha_innobase::final_drop_index(
     }
   
     row_mysql_unlock_data_dictionary(trx);
     goto func_exit;
    }
   
  - trx_set_dict_operation(trx, TRX_DICT_OP_INDEX);
  -
    /* Drop indexes marked to be dropped */
   
    row_mysql_lock_data_dictionary(trx);
   
    index = dict_table_get_first_index(prebuilt->table);
   
  @@ -1159,12 +1163,13 @@ ha_innobase::final_drop_index(
    dict_table_check_for_dup_indexes(prebuilt->table);
   #endif
    row_mysql_unlock_data_dictionary(trx);
   
   func_exit:
    trx_commit_for_mysql(trx);
  + trx_commit_for_mysql(prebuilt->trx);
   
    /* Flush the log to reduce probability that the .frm files and
    the InnoDB data dictionary get out-of-sync if the user runs
    with innodb_flush_log_at_trx_commit = 0 */
   
    log_buffer_flush_to_disk();
  
  (18:28:43) Heikki: Let me look
  (18:29:05) vasil: this is the change inside drop_index(), that is supposed to "Lock the user table within prebuilt->trx"
  (18:29:26) Heikki:   trans_register_ha(user_thd, FALSE, ht);
  + prebuilt->trx->active_trans = 1;
  (18:29:34) Heikki: I think the above code should be removed
  (18:29:53) Heikki: MySQL is not interested in InnoDB's transaction in this case
  (18:30:33) Heikki: Alternatively, we should use innobase_commit() instead of trx_commit_...
  (18:31:01) vasil: but there are many places in ::add_index() where it could return before reaching the trx_commit...
  (18:31:12) vasil: leaving active_traans=1
  (18:31:56) Heikki: Does Marko handle the errors with trx_rollback()?
  (18:32:08) vasil: let me see..
  (18:32:30) Heikki: It is risky to leave error handling to MySQL :(
  (18:32:35) vasil: 
   651         if (UNIV_UNLIKELY(error)) {
   652 err_exit:
   653                 mem_heap_free(heap);
   654                 trx_general_rollback_for_mysql(trx, FALSE, NULL);
   655                 trx_free_for_mysql(trx);
   656                 trx_commit_for_mysql(prebuilt->trx);
   657                 DBUG_RETURN(error);
   658         }
  
  (18:32:43) Heikki: Ok
  (18:33:25) Heikki: Please remove the ha_register... and active_trx =1 ....
  (18:33:42) Heikki: Then check if it prints something
  (18:34:08) Heikki: I believe MySQL is not interested in how the engine does the index build
  (18:34:11) vasil: why remove ha_register?
  (18:34:28) Heikki: Because there is no transaction visible to MySQL
  (18:34:53) vasil: the ha_register call was there from before
  (18:35:09) Heikki: Registers that InnoDB takes part in an SQL statement, so that MySQL knows to
  roll back the statement if the statement results in an error. This MUST be
  called for every SQL statement that may be rolled back by MySQL. Calling this
  several times to register the same statement is allowed, too. 
  (18:36:01) Heikki: Hmm
  (18:36:17) Heikki: Obviously, MySQL does NOT call commit at the end
  (18:36:36) Heikki: Because then innobase_commit() would set active_trx=0!
  (18:37:00) Heikki: Ok, maybe MySQL thinks CREATE INDEX is NOT a transactional statement
  (18:37:21) Heikki: Then, .._register_.. should be removed
  (18:37:51) Heikki: It is logical this way. If it also passes test, even better
  (18:38:21) vasil: ha_registrer in add_index() was added in r1845 and in drop_index() in r2128, let me read the comments..
  (18:38:55) vasil: 
  ------------------------------------------------------------------------
  r1845 | marko | 2007-09-13 13:31:54 +0300 (Thu, 13 Sep 2007) | 3 lines
  
  branches/zip: Move the code related to fast index creation
  (smart ALTER TABLE) from ha_innodb.cc to a separate module, handler0alter.cc.
  
  (18:39:05) Heikki: One thing you must check is that MySQL does write the CREATE INDEX in the binlog, even if we remove the _register_
  (18:39:41) Heikki: I assume Marko did not know if MySQL thinks CREATE INDEX is transactional or not
  (18:39:49) Heikki: He thought it is transactional
  (18:39:53) vasil: 
  ------------------------------------------------------------------------
  r2128 | marko | 2007-11-29 12:34:55 +0200 (Thu, 29 Nov 2007) | 5 lines
  
  branches/zip: ha_innobase::final_drop_index(): Allocate a separate transaction
  for dropping the index trees, and set the dictionary operation flag, similar
  to what ha_innobase::add_index() does.  This should ensure correct crash
  recovery.
  
  (18:40:10) Heikki: Ok
  (18:40:17) vasil: how do you know CREATE INDEX is not transactional?
  (18:40:33) Heikki: You cannot roll it back
  (18:40:44) vasil: ok
  (18:41:03) Heikki: MySQL devs probably thought this way
  (18:44:15) vasil: hmm
  (18:44:21) vasil: about r1845
  (18:45:00) vasil: the comments says "move the code" but it is actually "move and change the code"
  (18:45:28) Heikki: Well
  (18:45:29) vasil: the code that is deleted from ha_innodb is this:
  (18:45:32) vasil: 
  -       update_thd(ha_thd());
  -
  -       heap = mem_heap_create(1024);
  -
  -       /* In case MySQL calls this in the middle of a SELECT query, release
  -       possible adaptive hash latch to avoid deadlocks of threads. */
  -       trx_search_latch_release_if_reserved(check_trx_exists(user_thd));
  -
  -       trx = trx_allocate_for_mysql();
  -       trx_start_if_not_started(trx);
  -
  -       innobase_register_stmt(ht, user_thd);
  -
  -       trx->mysql_thd = user_thd;
  
  (18:45:38) vasil: (in add_index)
  (18:45:48) inaam left the room.
  (18:45:52) vasil: but the new one in handler0alter is this:
  (18:46:16) vasil: 
  +       update_thd(ha_thd());
  +
  +       heap = mem_heap_create(1024);
  +
  +       /* In case MySQL calls this in the middle of a SELECT query, release
  +       possible adaptive hash latch to avoid deadlocks of threads. */
  +       trx_search_latch_release_if_reserved(check_trx_exists(user_thd));
  +
  +       trx = trx_allocate_for_mysql();
  +       trx_start_if_not_started(trx);
  +
  +       trans_register_ha(user_thd, FALSE, ht);
  +
  +       trx->mysql_thd = user_thd;
  
  (18:46:48) vasil: innobase_register_stmt(ht, user_thd); was substituted with trans_register_ha(user_thd, FALSE, ht); during the move
  (18:46:49) Heikki: I do not see how MySQL could call it in the middle of a SELECT query!
  (18:46:59) Heikki: Yes
  (18:47:21) Heikki: Did Marko change innobase_register_stmt() code too?
  (18:48:05) vasil: not in this commit r1845
  (18:48:54) Heikki: Anyway, please test a version where you remove the register thing
  (18:49:08) vasil: and active_trans=1?
  (18:49:15) Heikki: Remove that, too
  (18:49:35) Heikki: innobase_register_stmt(
  /*===================*/
          handlerton*     hton,   /* in: Innobase hton */
          THD*    thd)    /* in: MySQL thd (connection) object */
  {
          DBUG_ASSERT(hton == innodb_hton_ptr);
          /* Register the statement */
          trans_register_ha(thd, FALSE, hton);
  }
  
  (18:50:23) Heikki: looks pretty much the same as what Marko has in the later version
  (18:50:43) vasil: innobase_register_stmt() was added in add_index() in r1584
  (18:50:47) vasil: 
  r1584 | marko | 2007-06-18 15:46:42 +0300 (Mon, 18 Jun 2007) | 12 lines
  
  branches/zip: ha_innobase::add_index(): Split some assertions.
  Remove the variable parent_trx.
  
  Call innobase_register_stmt() in order to work around a MySQL bug
  in mysql_alter_table(), which, as of
  
  ChangeSet@1.2482.61.2, 2007-06-07 16:37:15+02:00, joerg@trift2. +8 -0
  
  commits the transaction before calling ha_innobase::add_index().
  Without re-registering the statement, the ha_commit_stmt(thd)
  in mysql_alter_table() would not invoke innobase_commit.
  
  (18:51:56) Heikki: But it does not seem to invoke it now, because active_trans is left 1!
  (18:54:15) Heikki: Apparently, there has been confusion also among MySQL devs whether CREATE INDEX is transactional or not
  (18:54:45) vasil: :-(
  (18:54:53) Heikki: The most robust way is to handle all commits and rollbacks internally inside InnoDB and not tell MySQL anything about InnoDB's internal transactions
  (18:55:01) Heikki: That is my idea
  (18:55:20) Heikki: Then MySQL cannot spoil the logic of the code
  (18:55:59) vasil: mysql_alter_table() is ~1100 lines
  (18:56:08) vasil: and you suggest what?
  (18:56:43) Heikki: I suggest removing the ..._register_... thing and active_trans = 1
  (18:57:08) Heikki: Those things tell MySQL that there is a transaction going on
  (18:57:14) Heikki: Better not to tell
  (18:57:29) vasil: and possibly ignoring the above comment in r1584, "Call innobase_register_stmt() in order to work around a MySQL bug
  in mysql_alter_table()........."
  (18:57:32) vasil: ?
  (18:57:36) Heikki: Yes
  (18:57:38) vasil: ok
  (18:57:44) vasil: same for drop_index?
  (18:57:48) Heikki: Yes
  (18:58:51) vasil: testing
  Index: handler/handler0alter.cc
  ===================================================================
  --- handler/handler0alter.cc (revision 2498)
  +++ handler/handler0alter.cc (working copy)
  @@ -632,14 +632,14 @@ ha_innobase::add_index(
   
    /* Create a background transaction for the operations on
    the data dictionary tables. */
    trx = trx_allocate_for_mysql();
    trx_start_if_not_started(trx);
   
  - trans_register_ha(user_thd, FALSE, ht);
  - prebuilt->trx->active_trans = 1;
  + //trans_register_ha(user_thd, FALSE, ht);
  + //prebuilt->trx->active_trans = 1;
   
    trx->mysql_thd = user_thd;
    trx->mysql_query_str = thd_query(user_thd);
   
    innodb_table = indexed_table
     = dict_table_get(prebuilt->table->name, FALSE);
  @@ -1081,14 +1081,14 @@ ha_innobase::final_drop_index(
   
    /* Create a background transaction for the operations on
    the data dictionary tables. */
    trx = trx_allocate_for_mysql();
    trx_start_if_not_started(trx);
   
  - trans_register_ha(user_thd, FALSE, ht);
  - prebuilt->trx->active_trans = 1;
  + //trans_register_ha(user_thd, FALSE, ht);
  + //prebuilt->trx->active_trans = 1;
   
    trx->mysql_thd = user_thd;
    trx->mysql_query_str = thd_query(user_thd);
   
    /* Flag this transaction as a dictionary operation, so that
    the data dictionary will be locked in crash recovery. */
  
  (18:59:07) vasil: not warnings
  (18:59:22) Heikki: Did it create the indexes
  (18:59:36) vasil: I did test only removing active_trans=1 and it removed the warnings too
  (18:59:38) vasil: dunno
  (18:59:54) Heikki: That is the most important thing to check :)
  (19:00:10) vasil: :)
  (19:00:38) vasil: it is some mysqltest that is 610 lines
  (19:00:48) vasil: and it happens at the end
  (19:01:02) vasil: lets see how may add index statements...
  (19:01:11) vasil: 0
  (19:01:26) Heikki: Mostly I am concerned that MySQL might work wrong without that _register_ thing
  (19:03:28) vasil: could be
  (19:03:49) Heikki: You need to check it still calls ::add_index()
  (19:05:15) vasil: well, the change we made is inside ::add_index() how could it result in mysql stopping to call ::add_index()?
  (19:05:39) vasil: if it calls it twice...
  (19:05:43) Heikki: :-D
  (19:08:34) vasil: I guess it must have created the index, because the test is doing SHOW INDEX after CREATE INDEX and after DROP INDEX
  (19:08:43) vasil: the test would have failed if the index was not created
  (19:09:10) Heikki: You need to check that a query using that index will have the right EXPLAIN and result
  (19:15:04) vasil: this is with the patch:
  +CREATE TABLE t (a INT) ENGINE=innodb;
  +CREATE INDEX ti ON t(a);
  +INSERT INTO t VALUES (1), (2), (3);
  +EXPLAIN SELECT * FROM t WHERE a=2;
  +id select_type table type possible_keys key key_len ref rows Extra
  +1 SIMPLE t ref ti ti 5 const 1 Using where; Using index
  +SELECT * FROM t WHERE a=2;
  +a
  +2
  
  (19:15:15) Heikki: :)
  (19:15:46) vasil: this is with the original code:
  +CREATE TABLE t (a INT) ENGINE=innodb;
  +CREATE INDEX ti ON t(a);
  +INSERT INTO t VALUES (1), (2), (3);
  +EXPLAIN SELECT * FROM t WHERE a=2;
  +id select_type table type possible_keys key key_len ref rows Extra
  +1 SIMPLE t ref ti ti 5 const 1 Using where; Using index
  +SELECT * FROM t WHERE a=2;
  +a
  +2
  
  (19:15:59) vasil: it is the same
  (19:16:06) vasil: do you think this is sufficient?
  (19:16:20) Heikki: No, you need to do some manual tests, too
  (19:16:28) vasil: this is manual test
  (19:16:37) Heikki: Several of them
  (19:16:46) vasil: what should they do?
  (19:17:13) Heikki: Test tables of different sizes, different indexes
  (19:17:27) Heikki: CREATE several indexes at a time
  (19:19:14) Heikki: Dinner time -->
  --- cut ---

Approved by:	Heikki

Add the patches that are needed to make autotest.sh succeed.

Fixed the issue where an unchanged blob column that is part of the
primary key as well is lost if it is externally stored.

The fix is provided by Marko.

Reviewed by: Sunny

This is to fix an unintended side effect of file_format_check changes.
We were reading the trx system page (TRX_SYS_PAGE_NO) before starting
recovery and that resulted in redo logs not being applied to the page.
The fix is to force a reread by calling buf_pool_invalidate().
This, however, made necessary that any writes to page are deferred to
until after the redo log application.

Reviewed by: Sunny