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Overview
| Comment: | Do not attempt to reset a connection if it has been closed. Also, prevent any potential GC race while resetting a connection. Keep track of the total number of connections successfully opened and closed from any of the pools. Enhance test for ticket [996d13cd87] to make sure that at least one connection was opened and closed from a connection pool. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
7b3fe92dcb994e0af39ec6937c70abda |
| User & Date: | mistachkin 2012-05-03 13:44:30 |
Context
|
2012-05-03
| ||
| 15:11 | Fix a couple more potential GC race conditions. check-in: ed16f61cf7 user: mistachkin tags: trunk | |
| 13:44 | Do not attempt to reset a connection if it has been closed. Also, prevent any potential GC race while resetting a connection. Keep track of the total number of connections successfully opened and closed from any of the pools. Enhance test for ticket [996d13cd87] to make sure that at least one connection was opened and closed from a connection pool. check-in: 7b3fe92dcb user: mistachkin tags: trunk | |
| 13:04 | Stop creating the CriticalHandle derived classes via implicit operator conversions. Simplify test case for ticket [996d13cd87]. check-in: 29b506224a user: mistachkin tags: trunk | |
Changes
Changes to System.Data.SQLite/SQLite3.cs.
289 289 { 290 290 SQLiteConnectionPool.ClearPool(_fileName); 291 291 } 292 292 293 293 internal override int CountPool() 294 294 { 295 295 Dictionary<string, int> counts = null; 296 + int openCount = 0; 297 + int closeCount = 0; 296 298 int totalCount = 0; 297 299 298 300 SQLiteConnectionPool.GetCounts(_fileName, 299 - ref counts, ref totalCount); 301 + ref counts, ref openCount, ref closeCount, 302 + ref totalCount); 300 303 301 304 return totalCount; 302 305 } 303 306 304 307 internal override void SetTimeout(int nTimeoutMS) 305 308 { 306 309 int n = UnsafeNativeMethods.sqlite3_busy_timeout(_sql, nTimeoutMS);
Changes to System.Data.SQLite/SQLiteBase.cs.
392 392 if (n > 0) throw new SQLiteException(n, GetLastError(hdl, db)); 393 393 } 394 394 } 395 395 396 396 internal static void ResetConnection(SQLiteConnectionHandle hdl, IntPtr db) 397 397 { 398 398 if ((hdl == null) || (db == IntPtr.Zero)) return; 399 + if (hdl.IsClosed || hdl.IsInvalid) return; 399 400 lock (hdl) 400 401 { 401 402 IntPtr stmt = IntPtr.Zero; 402 403 int n; 403 404 do 404 405 { 405 406 stmt = UnsafeNativeMethods.sqlite3_next_stmt(db, stmt); ................................................................................ 415 416 416 417 if (IsAutocommit(db) == false) // a transaction is pending on the connection 417 418 { 418 419 n = UnsafeNativeMethods.sqlite3_exec(db, ToUTF8("ROLLBACK"), IntPtr.Zero, IntPtr.Zero, out stmt); 419 420 if (n > 0) throw new SQLiteException(n, GetLastError(hdl, db)); 420 421 } 421 422 } 423 + GC.KeepAlive(hdl); 422 424 } 423 425 424 426 internal static bool IsAutocommit(IntPtr db) 425 427 { 426 428 if (db == IntPtr.Zero) return false; 427 429 return (UnsafeNativeMethods.sqlite3_get_autocommit(db) == 1); 428 430 }
Changes to System.Data.SQLite/SQLiteConnectionPool.cs.
5 5 * Released to the public domain, use at your own risk! 6 6 ********************************************************/ 7 7 8 8 namespace System.Data.SQLite 9 9 { 10 10 using System; 11 11 using System.Collections.Generic; 12 + using System.Threading; 12 13 13 14 internal static class SQLiteConnectionPool 14 15 { 15 16 /// <summary> 16 17 /// Keeps track of connections made on a specified file. The PoolVersion dictates whether old objects get 17 18 /// returned to the pool or discarded when no longer in use. 18 19 /// </summary> ................................................................................ 35 36 private static SortedList<string, Pool> _connections = new SortedList<string, Pool>(StringComparer.OrdinalIgnoreCase); 36 37 37 38 /// <summary> 38 39 /// The default version number new pools will get 39 40 /// </summary> 40 41 private static int _poolVersion = 1; 41 42 43 + /// <summary> 44 + /// The number of connections successfully opened from any pool. 45 + /// This value is incremented by the Remove method. 46 + /// </summary> 47 + private static int _poolOpened = 0; 48 + 49 + /// <summary> 50 + /// The number of connections successfully closed from any pool. 51 + /// This value is incremented by the Add method. 52 + /// </summary> 53 + private static int _poolClosed = 0; 54 + 42 55 /// <summary> 43 56 /// Counts the number of pool entries matching the specified file name. 44 57 /// </summary> 45 58 /// <param name="fileName">The file name to match or null to match all files.</param> 46 59 /// <param name="counts">The pool entry counts for each matching file.</param> 60 + /// <param name="openCount">The total number of connections successfully opened from any pool.</param> 61 + /// <param name="closeCount">The total number of connections successfully closed from any pool.</param> 47 62 /// <param name="totalCount">The total number of pool entries for all matching files.</param> 48 63 internal static void GetCounts( 49 64 string fileName, 50 65 ref Dictionary<string, int> counts, 66 + ref int openCount, 67 + ref int closeCount, 51 68 ref int totalCount 52 69 ) 53 70 { 54 71 lock (_connections) 55 72 { 73 + openCount = _poolOpened; 74 + closeCount = _poolClosed; 75 + 56 76 if (counts == null) 57 77 { 58 78 counts = new Dictionary<string, int>( 59 79 StringComparer.OrdinalIgnoreCase); 60 80 } 61 81 62 82 if (fileName != null) ................................................................................ 128 148 129 149 while (poolQueue.Count > 0) 130 150 { 131 151 WeakReference cnn = poolQueue.Dequeue(); 132 152 SQLiteConnectionHandle hdl = cnn.Target as SQLiteConnectionHandle; 133 153 if ((hdl != null) && !hdl.IsClosed && !hdl.IsInvalid) 134 154 { 155 + Interlocked.Increment(ref _poolOpened); 135 156 return hdl; 136 157 } 137 158 GC.KeepAlive(hdl); 138 159 } 139 160 return null; 140 161 } 141 162 } ................................................................................ 146 167 /// </summary> 147 168 internal static void ClearAllPools() 148 169 { 149 170 lock (_connections) 150 171 { 151 172 foreach (KeyValuePair<string, Pool> pair in _connections) 152 173 { 153 - while (pair.Value.Queue.Count > 0) 174 + if (pair.Value == null) 175 + continue; 176 + 177 + Queue<WeakReference> poolQueue = pair.Value.Queue; 178 + 179 + while (poolQueue.Count > 0) 154 180 { 155 - WeakReference cnn = pair.Value.Queue.Dequeue(); 181 + WeakReference cnn = poolQueue.Dequeue(); 156 182 SQLiteConnectionHandle hdl = cnn.Target as SQLiteConnectionHandle; 157 183 if (hdl != null) 158 184 { 159 185 hdl.Dispose(); 160 186 } 161 187 GC.KeepAlive(hdl); 162 188 } ................................................................................ 223 249 { 224 250 ResizePool(queue, true); 225 251 226 252 Queue<WeakReference> poolQueue = queue.Queue; 227 253 if (poolQueue == null) return; 228 254 229 255 poolQueue.Enqueue(new WeakReference(hdl, false)); 256 + Interlocked.Increment(ref _poolClosed); 230 257 GC.KeepAlive(hdl); 231 258 } 232 259 else 233 260 { 234 261 hdl.Close(); 235 262 } 236 263 }
Changes to Tests/tkt-996d13cd87.eagle.
52 52 int errors = 0; 53 53 54 54 // 55 55 // NOTE: This is the total number of test threads to create. 56 56 // 57 57 int count = 100; 58 58 59 + // 60 + // NOTE: This is the total number of times we should force a full 61 + // garbage collection. 62 + // 63 + int gcCount = 2; 64 + 59 65 // 60 66 // NOTE: Create a random number generator suitable for waiting a 61 67 // random number of milliseconds between each attempt to 62 68 // cause the race condition on a given thread. 63 69 // 64 70 Random random = new Random(); 65 71 ................................................................................ 129 135 // 130 136 goEvent.WaitOne(); 131 137 132 138 // 133 139 // NOTE: Wait a random number of milliseconds before forcing a 134 140 // full garbage collection. 135 141 // 136 - Thread.Sleep(random.Next(0, 1000)); 137 - GC.GetTotalMemory(true); 142 + for (int index = 0; index < gcCount; index++) 143 + { 144 + Thread.Sleep(random.Next(0, 1000)); 145 + GC.GetTotalMemory(true); 146 + } 138 147 } 139 148 catch (Exception e) 140 149 { 141 150 Interlocked.Increment(ref errors); 142 151 Trace.WriteLine(e); 143 152 } 144 153 }; ................................................................................ 208 217 } 209 218 }] true true true results errors System.Data.SQLite.dll] 210 219 211 220 list $code $results \ 212 221 [expr {[info exists errors] ? $errors : ""}] \ 213 222 [expr {$code eq "Ok" ? [catch { 214 223 object invoke _Dynamic${id}.Test${id} Main 215 - } result] : [set result ""]}] $result 224 + } result] : [set result ""]}] $result \ 225 + [expr {[object invoke -flags +NonPublic \ 226 + System.Data.SQLite.SQLiteConnectionPool _poolOpened] > 0}] \ 227 + [expr {[object invoke -flags +NonPublic \ 228 + System.Data.SQLite.SQLiteConnectionPool _poolClosed] > 0}] 216 229 } -cleanup { 217 230 object invoke System.Data.SQLite.SQLiteConnection ClearAllPools 218 231 object invoke GC GetTotalMemory true 219 232 220 233 cleanupDb $fileName 221 234 222 235 unset -nocomplain result results errors code sql dataSource id db fileName 223 236 } -constraints \ 224 237 {eagle monoBug28 command.sql compile.DATA SQLite System.Data.SQLite} -match \ 225 -regexp -result {^Ok System#CodeDom#Compiler#CompilerResults#\d+ \{\} 0 \d+$}} 238 +regexp -result {^Ok System#CodeDom#Compiler#CompilerResults#\d+ \{\} 0 \d+ True\ 239 +True$}} 226 240 227 241 ############################################################################### 228 242 229 243 runSQLiteTestEpilogue 230 244 runTestEpilogue