From: Date: June 11 2008 8:31pm
Subject: bzr commit into mysql-6.0-falcon branch (vvaintroub:2699) Bug#37080
List-Archive: http://lists.mysql.com/commits/47752
X-Bug: 37080
Message-Id: <200806111831.m5BIVL24019943@mail.mysql.com>
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#At bzr+ssh://bk-internal.mysql.com/bzrroot/server/mysql-6.0-falcon/

 2699 Vladislav Vaintroub	2008-06-11
      Bug#37080 - Falcon deadlock on concurrent insert and truncate
      
      Problem: 
      Two threads, one processing TRUNCATE and gopher processing INSERT acquire 
      the same locks, SerlialLog::syncSections and Table::syncObject in different 
      order 
      
      Solution:
      Rearrange locks, so that syncSections is always locked before 
      Table::syncObject. For this, move lock to syncSection from 
      SRLDropTable::append() up the stack, into to Database::dropTable() 
      Database::truncateTable()
added:
  mysql-test/suite/falcon/r/falcon_bug_37080.result
  mysql-test/suite/falcon/t/falcon_bug_37080.test
modified:
  storage/falcon/Database.cpp
  storage/falcon/SRLDropTable.cpp

per-file messages:
  mysql-test/suite/falcon/r/falcon_bug_37080.result
    result file for Bug#37080
  mysql-test/suite/falcon/t/falcon_bug_37080.test
    test case for Bug#37080
    
    2 concurrent connections, one sending 1000 INSERTs and 
    another 100 TRUNCATEs.
    
    output is completely ignored, we're interested in deadlocks
  storage/falcon/Database.cpp
    moved syncSections exclusive lock from SRLDropTable::append() 
    to Database:dropTable()  and Database::truncateTable()
    to avoid deadlock
  storage/falcon/SRLDropTable.cpp
    moved syncSections exclusive lock from SRLDropTable::append() 
    to Database:dropTable()  and Database::truncateTable()
    to avoid deadlock
=== added file 'mysql-test/suite/falcon/r/falcon_bug_37080.result'
--- a/mysql-test/suite/falcon/r/falcon_bug_37080.result	1970-01-01 00:00:00 +0000
+++ b/mysql-test/suite/falcon/r/falcon_bug_37080.result	2008-06-11 18:31:05 +0000
@@ -0,0 +1,5 @@
+*** Bug #37080 ***
+SET @@storage_engine = 'Falcon';
+DROP TABLE IF EXISTS t;
+CREATE TABLE t(i int);
+DROP TABLE t;

=== added file 'mysql-test/suite/falcon/t/falcon_bug_37080.test'
--- a/mysql-test/suite/falcon/t/falcon_bug_37080.test	1970-01-01 00:00:00 +0000
+++ b/mysql-test/suite/falcon/t/falcon_bug_37080.test	2008-06-11 18:31:05 +0000
@@ -0,0 +1,50 @@
+--source include/have_falcon.inc
+#
+# Bug#37080: Falcon deadlock on parallel TRUNCATE  and INSERT
+# 
+--echo *** Bug #37080 ***
+
+# ----------------------------------------------------- #
+# --- Initialisation                                --- #
+# ----------------------------------------------------- #
+let $engine = 'Falcon';
+eval SET @@storage_engine = $engine;
+
+--disable_warnings
+DROP TABLE IF EXISTS t;
+--enable_warnings
+
+
+CREATE TABLE t(i int);
+connect (conn1,localhost,root,,);
+# ----------------------------------------------------- #
+# --- Test                                          --- #
+# ----------------------------------------------------- #
+
+
+let $num=10000;
+--disable_query_log
+--disable_abort_on_error
+while ($num)
+{
+   connection conn1;
+   --send insert into t values(1);
+   connection default;
+   --send truncate table t;
+   connection conn1;
+   --reap
+   connection default;
+   --reap 
+   dec $num;
+}
+--enable_abort_on_error
+--enable_query_log
+
+# ----------------------------------------------------- #
+# --- Check                                         --- #
+# ----------------------------------------------------- #
+
+# ----------------------------------------------------- #
+# --- Final cleanup                                 --- #
+# ----------------------------------------------------- #
+DROP TABLE t;

=== modified file 'storage/falcon/Database.cpp'
--- a/storage/falcon/Database.cpp	2008-05-09 19:58:50 +0000
+++ b/storage/falcon/Database.cpp	2008-06-11 18:31:05 +0000
@@ -1452,6 +1452,10 @@ void Database::dropTable(Table *table, T
 	
 	invalidateCompiledStatements(table);
 	table->drop(transaction);
+
+	//Lock sections (factored out of SRLDropTable to avoid a deadlock)
+	Sync syncSections(&serialLog->syncSections, "Database::dropTable");
+	syncSections.lock(Exclusive);
 	table->expunge(getSystemTransaction());
 	delete table;
 }
@@ -1474,8 +1478,14 @@ void Database::truncateTable(Table *tabl
 	Sync syncTbl(&syncTables, "Database::truncateTable");
 	syncTbl.lock(Shared);
 	
-	// No table access until truncate completes
+	//Lock sections (factored out of SRLDropTable to avoid a deadlock)
+	//The lock order (serialLog->syncSections before table->syncObject) is 
+	//important
+
+	Sync syncSections(&serialLog->syncSections, "Database::truncateTable");
+	syncSections.lock(Exclusive);
 	
+	// No table access until truncate completes
 	Sync syncObj(&table->syncObject, "Database::truncateTable");
 	syncObj.lock(Exclusive);
 	

=== modified file 'storage/falcon/SRLDropTable.cpp'
--- a/storage/falcon/SRLDropTable.cpp	2007-09-20 15:44:25 +0000
+++ b/storage/falcon/SRLDropTable.cpp	2008-06-11 18:31:05 +0000
@@ -46,9 +46,6 @@ SRLDropTable::~SRLDropTable()
 
 void SRLDropTable::append(Dbb *dbb, TransId transId, int section)
 {
-	Sync syncSections(&log->syncSections, "SRLDropTable::append");
-	syncSections.lock(Exclusive);
-
 	START_RECORD(srlDropTable, "SRLDropTable::append");
 	putInt(dbb->tableSpaceId);
 	log->getTransaction(transId);