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3655 Jon Olav Hauglid 2009-10-19 Bug #30977 Concurrent statement using stored function and DROP FUNCTION breaks SBR Bug #48246 assert in close_thread_table Implement a fix for: Bug #41804 purge stored procedure cache causes mysterious hang for many minutes Bug #49972 Crash in prepared statements The problem was that concurrent execution of DML statements that use stored functions and DDL statements that drop/modify the same function might result in incorrect binary log in statement (and mixed) mode and therefore break replication. This patch fixes the problem by introducing metadata locking for stored procedures and functions. This is similar to what is done in Bug#25144 for views. Procedures and functions now are locked using metadata locks until the transaction is either committed or rolled back. This prevents other statements from modifying the procedure/function while it is being executed. This provides commit ordering - guaranteeing serializability across multiple transactions and thus fixes the reported binlog problem. Note that we do not take locks for top-level CALLs. This means that procedures called directly are not protected from changes by simultaneous DDL operations so they are executed at the state they had at the time of the CALL. By not taking locks for top-level CALLs, we still allow transactions to be started inside procedures. This patch also changes stored procedure cache invalidation. Upon a change of cache version, we no longer invalidate the entire cache, but only those routines which we use, only when a statement is executed that uses them. This patch also changes the logic of prepared statement validation. A stored procedure used by a prepared statement is now validated only once a metadata lock has been acquired. A version mismatch causes a flush of the obsolete routine from the cache and statement reprepare. Incompatible changes: 1) ER_LOCK_DEADLOCK is reported for a transaction trying to access a procedure/function that is locked by a DDL operation in another connection. 2) Procedure/function DDL operations are now prohibited in LOCK TABLES mode as exclusive locks must be taken all at once and LOCK TABLES provides no way to specifiy procedures/functions to be locked. Test cases have been added to sp-lock.test and rpl_sp.test. Work on this bug has very much been a team effort and this patch includes and is based on contributions from Davi Arnaut, Dmitry Lenev, Magne Mæhre and Konstantin Osipov.
63 lines
1.8 KiB
C++
63 lines
1.8 KiB
C++
/* -*- C++ -*- */
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/* Copyright (C) 2002 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#ifndef _SP_CACHE_H_
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#define _SP_CACHE_H_
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#ifdef USE_PRAGMA_INTERFACE
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#pragma interface /* gcc class implementation */
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#endif
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/*
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Stored procedures/functions cache. This is used as follows:
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* Each thread has its own cache.
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* Each sp_head object is put into its thread cache before it is used, and
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then remains in the cache until deleted.
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*/
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class sp_head;
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class sp_cache;
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/*
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Cache usage scenarios:
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1. Application-wide init:
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sp_cache_init();
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2. SP execution in thread:
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2.1 While holding sp_head* pointers:
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// look up a routine in the cache (no checks if it is up to date or not)
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sp_cache_lookup();
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sp_cache_insert();
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sp_cache_invalidate();
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2.2 When not holding any sp_head* pointers:
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sp_cache_flush_obsolete();
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3. Before thread exit:
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sp_cache_clear();
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*/
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void sp_cache_init();
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void sp_cache_clear(sp_cache **cp);
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void sp_cache_insert(sp_cache **cp, sp_head *sp);
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sp_head *sp_cache_lookup(sp_cache **cp, sp_name *name);
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void sp_cache_invalidate();
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void sp_cache_flush_obsolete(sp_cache **cp, sp_head **sp);
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ulong sp_cache_version();
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#endif /* _SP_CACHE_H_ */
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