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16 commits

Author SHA1 Message Date
Andrei Elkin
c8ae357341 MDEV-742 XA PREPAREd transaction survive disconnect/server restart
Lifted long standing limitation to the XA of rolling it back at the
transaction's
connection close even if the XA is prepared.

Prepared XA-transaction is made to sustain connection close or server
restart.
The patch consists of

    - binary logging extension to write prepared XA part of
      transaction signified with
      its XID in a new XA_prepare_log_event. The concusion part -
      with Commit or Rollback decision - is logged separately as
      Query_log_event.
      That is in the binlog the XA consists of two separate group of
      events.

      That makes the whole XA possibly interweaving in binlog with
      other XA:s or regular transaction but with no harm to
      replication and data consistency.

      Gtid_log_event receives two more flags to identify which of the
      two XA phases of the transaction it represents. With either flag
      set also XID info is added to the event.

      When binlog is ON on the server XID::formatID is
      constrained to 4 bytes.

    - engines are made aware of the server policy to keep up user
      prepared XA:s so they (Innodb, rocksdb) don't roll them back
      anymore at their disconnect methods.

    - slave applier is refined to cope with two phase logged XA:s
      including parallel modes of execution.

This patch does not address crash-safe logging of the new events which
is being addressed by MDEV-21469.

CORNER CASES: read-only, pure myisam, binlog-*, @@skip_log_bin, etc

Are addressed along the following policies.
1. The read-only at reconnect marks XID to fail for future
   completion with ER_XA_RBROLLBACK.

2. binlog-* filtered XA when it changes engine data is regarded as
   loggable even when nothing got cached for binlog.  An empty
   XA-prepare group is recorded. Consequent Commit-or-Rollback
   succeeds in the Engine(s) as well as recorded into binlog.

3. The same applies to the non-transactional engine XA.

4. @@skip_log_bin=OFF does not record anything at XA-prepare
   (obviously), but the completion event is recorded into binlog to
   admit inconsistency with slave.

The following actions are taken by the patch.

At XA-prepare:
   when empty binlog cache - don't do anything to binlog if RO,
   otherwise write empty XA_prepare (assert(binlog-filter case)).

At Disconnect:
   when Prepared && RO (=> no binlogging was done)
     set Xid_cache_element::error := ER_XA_RBROLLBACK
     *keep* XID in the cache, and rollback the transaction.

At XA-"complete":
   Discover the error, if any don't binlog the "complete",
   return the error to the user.

Kudos
-----
Alexey Botchkov took to drive this work initially.
Sergei Golubchik, Sergei Petrunja, Marko Mäkelä provided a number of
good recommendations.
Sergei Voitovich made a magnificent review and improvements to the code.
They all deserve a bunch of thanks for making this work done!
2020-03-14 22:45:48 +02:00
Sergei Golubchik
81cffda2e6 perfschema transaction instrumentation related changes 2020-03-10 19:24:23 +01:00
Sergei Golubchik
05779bc6f1 perfschema mdl related instrumentation changes 2020-03-10 19:24:22 +01:00
Sergei Golubchik
2ac3121af2 perfschema - various collateral cleanups and small changes 2020-03-10 19:24:22 +01:00
Andrei Elkin
dd3ffdbd92 MDEV-21659 XA rollback foreign_xid is allowed inside active XA
MDEV-21854 xa commit `xid` one phase for already prepared transaction must always error out

Added state and one-phase option checks to XA "external" commit/rollback
branches. While the XA standard does not prohibit it,
Commit and Rollback of an XA external to the current ongoing transaction
is not allowed; after all the current transaction may rollback
to not being able to revert that decision.
2020-03-09 20:40:52 +02:00
Sergey Vojtovich
607960c772 MDEV-21766 - Forbid XID with empty 'gtrid'
XA specification doesn't permit empty gtrid. It is now enforced by this
patch. This solution was agreed in favour of fixing InnoDB, which doesn't
expect empty XID since early 10.5.

Also fixed wrong assertion (and added a test cases) that didn't permit
64 bytes gtrid + 64 bytes bqual.
2020-02-28 22:27:55 +04:00
Marko Mäkelä
8336371441 Merge 10.4 into 10.5 2019-10-12 22:06:47 +03:00
Marko Mäkelä
dba743b653 Fix -Wunused-variable 2019-10-12 06:57:02 +03:00
Alexander Barkov
3e7e87ddcc MDEV-19897 Rename source code variable names from utf8 to utf8mb3 2019-06-28 12:37:04 +04:00
Sergey Vojtovich
1599825ffc trans_xa_detach() framework
Part of MDEV-7974 - backport fix for mysql bug#12161 (XA and binlog)
2019-04-25 15:06:40 +04:00
Sergey Vojtovich
210855ce5d Move XID_STATE::xid to XID_cache_element
Part of MDEV-7974 - backport fix for mysql bug#12161 (XA and binlog)
2019-04-25 15:06:40 +04:00
Sergey Vojtovich
b7fd7ce286 Moved normal transaction xid to implicit_xid
Part of MDEV-7974 - backport fix for mysql bug#12161 (XA and binlog)
2019-04-25 15:06:40 +04:00
Sergey Vojtovich
228514e52f Move XID_STATE::xa_state to XID_cache_element
Simplified away XA_NOTR, use XID_STATE::is_explicit_XA() instead.

Part of MDEV-7974 - backport fix for mysql bug#12161 (XA and binlog)
2019-04-25 15:06:40 +04:00
Sergey Vojtovich
a168cfb396 Move XID_state::xa_state handing inside xa.cc
Let xid_cache_insert()/xid_cache_delete() handle xa_state.

Let session tracker use is_explicit_XA() rather than xa_state != XA_NOTR.

Fixed open_tables() to refuse data access in XA_ROLLBACK_ONLY state.

Removed dead code from THD::cleanup(). It was supposed to be a reminder,
but it got messed up over time.

spider_internal_start_trx() is called either with XA_NOTR or XA_ACTIVE,
which is guarded by server callers. Thus is_explicit_XA() is acceptable
replacement for XA_ACTIVE check (which was likely wrong anyway).

Setting xa_state to XA_PREPARED in spider_internal_xa_prepare() isn't
meaningful, as this value is never accessed later. It can't be accessed
by current thread and it can't be recovered either. It can only be
accessed by spider internally, which never happens.

Make spider_xa_lock()/spider_xa_unlock() static.

Part of MDEV-7974 - backport fix for mysql bug#12161 (XA and binlog)
2019-04-25 15:06:40 +04:00
Sergey Vojtovich
f189f34ed4 Move XID_STATE::rm_error to XID_cache_element
XID_STATE::rm_error is never used by internal 2PC, it is intended to be
used by explicit XA only.

Also removed redundant xid reset from THD::init_for_queries(). Must've
been done already either by THD::transaction constructor or by
THD::cleanup().

Part of MDEV-7974 - backport fix for mysql bug#12161 (XA and binlog)
2019-04-25 15:06:40 +04:00
Sergey Vojtovich
07140f171d Just move, no code changes otherwise.
Part of MDEV-7974 - backport fix for mysql bug#12161 (XA and binlog)
2019-04-25 15:06:40 +04:00