On Oct 6, 2010, at 9:39 PM, Raj, Praveen wrote: > Hi Dan, > > For debugging purpose we use the QNX Momentics which is the IDE > provided by QNX. I believe to certain extent > we should be able to debug the issue using IDE. In what situations > does the shared memory block be zeroed. > I believe it should be zeroed when the db is closed or when WAL file > is checkpointed. Any other scenarios?
Following a checkpoint when the writer wraps around to the start of the log file. > Please provide pointers on what needs to be checked along with > "unixShmMap()" when the problem occurs. There is only one call to sqlite3OsShmMap() in wal.c. Try to stop the debugger when this function is called with iPage==1. At this point there should be a pointer to the first 32KB of mapped memory in pWal->apWiData[0]. It should not be full of zeroes as it is in the dumps that you sent. Check if this is the case. More specifically - 100 bytes or so into the buffer should not contain all zeroes. It should contain a bunch of 32-bit non-zero frame numbers. Then check if it is still the case after the call to sqlite3OsShmMap() has returned. Either way, you're looking for the point where that buffer pWal->apWiData[0] is overwritten with zeroes. Dan. > Thanks, > Praveen > > -----Original Message----- > From: sqlite-users-boun...@sqlite.org [mailto:sqlite-users-boun...@sqlite.org > ] On Behalf Of Dan Kennedy > Sent: Wednesday, October 06, 2010 7:37 PM > To: General Discussion of SQLite Database > Subject: Re: [sqlite] TestFixture 3.7.2 - Some WAL tests fail on QNX > OS > > > On Oct 6, 2010, at 8:15 PM, Raj, Praveen wrote: > >> Hello, >> >> I'm new to SQLite, so not sure what is the behavior of these failed >> tests on Unix/Linux. Are they successfully passing all the WAL >> journal mode tests on Unix? >> >> What could be happening when the shared memory (-shm file) is >> increased from 32k to 64k? >> Is a new 64k memory chunk allocated and old 32k data is copied here >> and then 32k is purged? > > At some point in the transaction, the first 32KB of shared-memory > are being zeroed. I'm not sure why this would happen. > > The WAL file looks Ok. And the header in the shared-memory looks > Ok. But most of the first 32KB of shared-memory has been zeroed > (it is likely that the whole thing was zeroed and then the header > rewritten). > > Maybe something about running the unixShmMap() function on QNX to > mmap() the second 32KB of space (we use a separate mapping > for each 32KB block) is zeroing the first. Somehow. Do you have > a good debugger for the platform? > > Dan. > > > > >> Any insights on whats happening here would be of great help. >> >> Thanks, >> Praveen >> >> -----Original Message----- >> From: sqlite-users-boun...@sqlite.org [mailto:sqlite-users-boun...@sqlite.org >> ] On Behalf Of Raj, Praveen >> Sent: Sunday, October 03, 2010 7:42 PM >> To: General Discussion of SQLite Database >> Subject: Re: [sqlite] TestFixture 3.7.2 - Some WAL tests fail on QNX >> OS >> >> Hi, >> >> Yes the files sizes of "test.db", "test.db-wal" and "test.db-shm" >> are 1024, 4333512 and 65536 bytes respectively as specified below. >> >> Most of the test scripts are failing when the -shm file size grows >> from 32kb to 64kb (though the "test.db-wal" >> file size varies for different test scripts). >> But there are cases in WAL tests where the size increases to 64kb, >> but the problem is not seen. >> Is there any problem while allocating/increasing shared memory, or >> is the WAL page indexes getting corrupted when shared memory >> increases? >> >> Please suggest some tips to find out the root cause for this issue. >> >> Thanks, >> Praveen >> ________________________________________ >> From: sqlite-users-boun...@sqlite.org [sqlite-users- >> boun...@sqlite.org] On Behalf Of Dan Kennedy [danielk1...@gmail.com] >> Sent: Saturday, October 02, 2010 2:39 PM >> To: General Discussion of SQLite Database >> Subject: Re: [sqlite] TestFixture 3.7.2 - Some WAL tests fail on QNX >> OS >> >> On Oct 1, 2010, at 2:20 PM, Raj, Praveen wrote: >> >>> Hi, >>> >>> I'm validating SQLite test suite version 3.7.2 on QNX operating >>> system. I have built the testfixture using SQLite amalgation file >>> and other related files/libraries. >>> >>> I ran the full test suite and most of the test cases are passing, >>> except some run in journal_mode = WAL. Test cases whose >>> autocheckpoint is turned off and large amount of >>> data is being inserted without checkpointing are failing. Other WAL >>> tests are passing. I tried increasing the stack size of the >>> testfixture process, but that didn't help. >>> >>> If i reduce the number of inserts or increase the WAL page size, >>> test cases are passing. I believe there is some corruption happening >>> with the WAL index while >>> inserting large number of rows. Here is an example (from SQLite test >>> suite) of the failure >>> (Purposefully added "PRAGMA integrity_check" at end of wal3-1.0) >> >> How large are the "test.db", "test.db-wal" and "test.db-shm" files >> on your system after the transaction in wal3-1.0? i.e. stick >> >> puts [file size test.db] >> puts [file size test.db-wal] >> puts [file size test.db-shm] >> >> or similar after the test case. >> >> Here the files are 1024, 4333512 and 65536 bytes. From what you are >> saying it sounds like the problem is occurring when the -shm file >> grows from 32KB to 64KB. >> >> Dan. >> >> >> _______________________________________________ >> sqlite-users mailing list >> sqlite-users@sqlite.org >> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users >> >> The information contained in this message may be confidential and >> legally protected under applicable law. The message is intended >> solely for the addressee(s). If you are not the intended recipient, >> you are hereby notified that any use, forwarding, dissemination, or >> reproduction of this message is strictly prohibited and may be >> unlawful. If you are not the intended recipient, please contact the >> sender by return e-mail and destroy all copies of the original >> message. >> >> _______________________________________________ >> sqlite-users mailing list >> sqlite-users@sqlite.org >> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users >> >> _______________________________________________ >> sqlite-users mailing list >> sqlite-users@sqlite.org >> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > > The information contained in this message may be confidential and > legally protected under applicable law. 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