On 3/12/15, Matthias Schmitt <freak002 at mmp.lu> wrote: > Hello, > > I know, I am touching a hot iron, when claiming that sqlite might have a > memory leak. But I am trying to debug memory leaks related to sqlite now > since 4 days and I am running against walls. > Here is my problem: > > - I am writing an iPhone app using iOS 8.2, Xcode 4.2, sqlite 3.8.8.3. > > - The memory leak appears in the iPhone simulator more often, than on an > original iPhone device, but it appears always.
Let's start with the basics: How do you know that the memory was in fact leaked and is not instead simply being held for reuse? > > - The leak appears with totally different type of queries. It might be, that > a leak appears in a specific query in one debug session and in another debug > session, it doesn?t (which makes it difficult to debug and drives me totally > nuts). For me it seems to be related to a timing/threading issue. This is > why it makes not much sense to offer some code here. > > - When debugging inside sqlite the leak is always related to the same code > line, independent from the type of database command (select, insert, > delete). > > - It appears always with the memory allocation in sqlite.c line 16872 in > function sqlite3MemMalloc > Here is the line: void *p = SQLITE_MALLOC( nByte ); > > - The leaked memory has always a size of nByte = 4344 bytes. > > - Here is a typical call stack up to the leaked code: > > 0 libsystem_malloc.dylib malloc_zone_malloc > 1 MYAPP sqlite3MemMalloc sqlite3.c:16872 > 2 MYAPP mallocWithAlarm sqlite3.c:20510 > 3 MYAPP sqlite3Malloc sqlite3.c:20541 > 4 MYAPP pcache1Alloc sqlite3.c:39749 > 5 MYAPP pcache1AllocPage sqlite3.c:39833 > 6 MYAPP pcache1FetchStage2 sqlite3.c:40266 > 7 MYAPP pcache1Fetch sqlite3.c:40367 > 8 MYAPP sqlite3PcacheFetch sqlite3.c:39119 > 9 MYAPP sqlite3PagerAcquire sqlite3.c:46573 > 10 MYAPP btreeGetPage sqlite3.c:54380 > 11 MYAPP getAndInitPage sqlite3.c:54435 > 12 MYAPP moveToRoot sqlite3.c:57233 > 13 MYAPP sqlite3BtreeMovetoUnpacked sqlite3.c:57465 > 14 MYAPP sqlite3VdbeExec sqlite3.c:74055 > 15 MYAPP sqlite3Step sqlite3.c:68839 > 16 MYAPP sqlite3_step sqlite3.c:68905 > 17 MYAPP -[FMResultSet nextWithError:] FMResultSet.m:155 > 18 MYAPP -[FMResultSet next] FMResultSet.m:150 > 19 MYAPP __40-[MYAPPAppDelegate loadPreferences]_block_invoke > MYAPPAppDelegate.m:323 > 20 MYAPP __30-[FMDatabaseQueue inDatabase:]_block_invoke > FMDatabaseQueue.m:150 > 21 libdispatch.dylib _dispatch_client_callout > 22 libdispatch.dylib _dispatch_barrier_sync_f_invoke > 23 MYAPP -[FMDatabaseQueue inDatabase:] FMDatabaseQueue.m:147 > 24 MYAPP -[MYAPPAppDelegate loadPreferences] MYAPPAppDelegate.m:321 > 25 MYAPP -[MYAPPAppDelegate application:didFinishLaunchingWithOptions:] > MYAPPAppDelegate.m:157 > 26 UIKit -[UIApplication > _handleDelegateCallbacksWithOptions:isSuspended:restoreState:] > 27 UIKit -[UIApplication > _callInitializationDelegatesForMainScene:transitionContext:] > 28 UIKit -[UIApplication _runWithMainScene:transitionContext:completion:] > 29 UIKit -[UIApplication workspaceDidEndTransaction:] > 30 FrontBoardServices __31-[FBSSerialQueue performAsync:]_block_invoke > 31 CoreFoundation __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ > 32 CoreFoundation __CFRunLoopDoBlocks > 33 CoreFoundation __CFRunLoopRun > 34 CoreFoundation CFRunLoopRunSpecific > 35 UIKit -[UIApplication _run] > 36 UIKit UIApplicationMain > 37 MYAPP main main.m:16 > 38 libdyld.dylib start > > Does anybody have an idea how to debug something like this? Any help would > be highly appreciated. > > Best regards > > Matthias Schmitt > > magic moving pixel s.a. > 23, Avenue Grande-Duchesse Charlotte > L-3441 Dudelange > Luxembourg > Phone: +352 54 75 75 > http://www.mmp.lu > > > > > _______________________________________________ > sqlite-users mailing list > sqlite-users at mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > -- D. Richard Hipp drh at sqlite.org
