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| author | Dmitry Shulga <Dmitry.Shulga@oracle.com> | 2012-12-06 15:59:15 +0600 |
|---|---|---|
| committer | Dmitry Shulga <Dmitry.Shulga@oracle.com> | 2012-12-06 15:59:15 +0600 |
| commit | 54769c281ec9cf7d52740ed5ca503c5d81ed1744 (patch) | |
| tree | 09347fd41ab35e614f325750babcb7973da605a2 /sql/transaction.cc | |
| parent | 46cfbf35f86a6ff63bdfcd85297bd8269efc2826 (diff) | |
| download | mariadb-git-54769c281ec9cf7d52740ed5ca503c5d81ed1744.tar.gz | |
This patch fixes bug#14729757 - MY_HASH_SEARCH(&XID_CACHE,
XID_STATE->XID.KEY(),
XID_STATE->XID.KEY_LENGTH())==0
This bug is a regression of bug#11759534 - 51855: RACE CONDITION
IN XA START.
The reason for regression is that the changes that fixes the original
bug wasn't merged from mysql-5.1 into mysql-5.5 and mysql-trunk.
Only null-merge was done for the patch changeset.
To incorporate lost changes the manual merge have been done.
Additionally the call of trans_rolback() was added into trans_xa_start()
in case if xid_cache_insert is failed() after transaction has been started.
If we don't call trans_rollback() we would never reset the flag
SERVER_STATUS_IN_TRANS in THD::server_status and therefore all subsequent
attempts to execute XA START in the connection where the error was occurred
will be failed since thd->in_active_multi_stmt_transaction() will return
the true every time when trans_xa_start is called.
The latest changes were absent in patch for mysql-5.1
Diffstat (limited to 'sql/transaction.cc')
| -rw-r--r-- | sql/transaction.cc | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/sql/transaction.cc b/sql/transaction.cc index 3359decbcd5..1623cd57d77 100644 --- a/sql/transaction.cc +++ b/sql/transaction.cc @@ -567,15 +567,19 @@ bool trans_xa_start(THD *thd) my_error(ER_XAER_RMFAIL, MYF(0), xa_state_names[xa_state]); else if (thd->locked_tables_mode || thd->in_active_multi_stmt_transaction()) my_error(ER_XAER_OUTSIDE, MYF(0)); - else if (xid_cache_search(thd->lex->xid)) - my_error(ER_XAER_DUPID, MYF(0)); else if (!trans_begin(thd)) { DBUG_ASSERT(thd->transaction.xid_state.xid.is_null()); thd->transaction.xid_state.xa_state= XA_ACTIVE; thd->transaction.xid_state.rm_error= 0; thd->transaction.xid_state.xid.set(thd->lex->xid); - xid_cache_insert(&thd->transaction.xid_state); + if (xid_cache_insert(&thd->transaction.xid_state)) + { + thd->transaction.xid_state.xa_state= XA_NOTR; + thd->transaction.xid_state.xid.null(); + trans_rollback(thd); + DBUG_RETURN(true); + } DBUG_RETURN(FALSE); } @@ -661,6 +665,16 @@ bool trans_xa_commit(THD *thd) if (!thd->transaction.xid_state.xid.eq(thd->lex->xid)) { + /* + xid_state.in_thd is always true beside of xa recovery procedure. + Note, that there is no race condition here between xid_cache_search + and xid_cache_delete, since we always delete our own XID + (thd->lex->xid == thd->transaction.xid_state.xid). + The only case when thd->lex->xid != thd->transaction.xid_state.xid + and xid_state->in_thd == 0 is in the function + xa_cache_insert(XID, xa_states), which is called before starting + client connections, and thus is always single-threaded. + */ XID_STATE *xs= xid_cache_search(thd->lex->xid); res= !xs || xs->in_thd; if (res) |