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  • How can I get SQL Server transactions to use record-level locks?

    - by Joe White
    We have an application that was originally written as a desktop app, lo these many years ago. It starts a transaction whenever you open an edit screen, and commits if you click OK, or rolls back if you click Cancel. This worked okay for a desktop app, but now we're trying to move to ADO.NET and SQL Server, and the long-running transactions are problematic. I found that we'll have a problem when multiple users are all trying to edit (different subsets of) the same table at the same time. In our old database, each user's transaction would acquire record-level locks to every record they modified during their transaction; since different users were editing different records, everyone gets their own locks and everything works. But in SQL Server, as soon as one user edits a record inside a transaction, SQL Server appears to get a lock on the entire table. When a second user tries to edit a different record in the same table, the second user's app simply locks up, because the SqlConnection blocks until the first user either commits or rolls back. I'm aware that long-running transactions are bad, and I know that the best solution would be to change these screens so that they no longer keep transactions open for a long time. But since that would mean some invasive and risky changes, I also want to research whether there's a way to get this code up and running as-is, just so I know what my options are. How can I get two different users' transactions in SQL Server to lock individual records instead of the entire table? Here's a quick-and-dirty console app that illustrates the issue. I've created a database called "test1", with one table called "Values" that just has ID (int) and Value (nvarchar) columns. If you run the app, it asks for an ID to modify, starts a transaction, modifies that record, and then leaves the transaction open until you press ENTER. I want to be able to start the program and tell it to update ID 1; let it get its transaction and modify the record; start a second copy of the program and tell it to update ID 2; have it able to update (and commit) while the first app's transaction is still open. Currently it freezes at step 4, until I go back to the first copy of the app and close it or press ENTER so it commits. The call to command.ExecuteNonQuery blocks until the first connection is closed. public static void Main() { Console.Write("ID to update: "); var id = int.Parse(Console.ReadLine()); Console.WriteLine("Starting transaction"); using (var scope = new TransactionScope()) using (var connection = new SqlConnection(@"Data Source=localhost\sqlexpress;Initial Catalog=test1;Integrated Security=True")) { connection.Open(); var command = connection.CreateCommand(); command.CommandText = "UPDATE [Values] SET Value = 'Value' WHERE ID = " + id; Console.WriteLine("Updating record"); command.ExecuteNonQuery(); Console.Write("Press ENTER to end transaction: "); Console.ReadLine(); scope.Complete(); } } Here are some things I've already tried, with no change in behavior: Changing the transaction isolation level to "read uncommitted" Specifying a "WITH (ROWLOCK)" on the UPDATE statement

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  • This Wed, Reading - Service Broker, Indexing, Normalisation, Sets, RI and Locking, Surrogate Keys

    - by tonyrogerson
    Registration is a must so we know numbers and for security, register here: http://sqlserverfaq.com/events/213/Service-Broker-Intro-Guidance-Indexing-Selection-Usage-Fragmentation-etc-Normalisation-Surrogate-Keys-Locking-considerations.aspx Network, learn, ask a question, meet other folk, get fed - these are all things that happen at user group events. These events are a really great opportunity to socialise in an informal learning experience - if you want your own exposure then come and do a 1 -...(read more)

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  • Read Committed isolation level, indexed views and locking behavior

    - by Michael Zilberstein
    From BOL, " Key-Range Locking " article: Key-range locks protect a range of rows implicitly included in a record set being read by a Transact-SQL statement while using the serializable transaction isolation level . The serializable isolation level requires that any query executed during a transaction must obtain the same set of rows every time it is executed during the transaction. A key range lock protects this requirement by preventing other transactions from inserting new rows whose...(read more)

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  • Do we need Record Level Locking when we already have Transaction for online ordering? (of concert ti

    - by Jian Lin
    For online ordering of concert seat or airline ticket, do we need Record Level Locking or is Transaction good enough? For concert ticket (say, seat Number 20B), or airline ticket (even with overbooking, the limit is 210, for example), I think the website cannot lock any record or begin transaction when showing the ticket purchase screen. But after the user clicks "Confirm Purchase", then the server should Begin a Transaction, Purchase Seat Number 20B, and try to Commit. If another user already bought Seat 20B in a previous transaction, then it is the "Commit" part that the current transaction will fail? So... we don't need Record Level Locking? Do Transactions always go serialized (one after another), so that's why we can know for sure there is no "race condition"? In what situation is Record Level Locking needed then?

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  • Screen sometimes inverts after locking

    - by hackedd
    Sometimes, when I wake up my computer from a screen lock, one of my screens is inverted. It does not always happen (maybe one in ten times) and it is not always the same screen. Re-locking and unlocking the screen a couple of times fixes the colors again. I have a dual monitor setup on an ATI Radeon HD 3450, using two HP screens connected over DVI. I am using the radeon driver, and according to jockey there are no additional drivers available for my system. Any ideas as to why this happens?

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  • Keyboard locking up in Visual Studio 2010

    - by Jim Wang
    One of the initiatives I’m involved with on the ASP.NET and Visual Studio teams is the Tactical Test Team (TTT), which is a group of testers who dedicate a portion of their time to roaming around and testing different parts of the product.  What this generally translates to is a day and a bit a week helping out with areas of the product that have been flagged as risky, or tackling problems that span both ASP.NET and Visual Studio.  There is also a separate component of this effort outside of TTT which is to help with customer scenarios and design. I enjoy being on TTT because it allows me the opportunity to look at the entire product and gain expertise in a wide range of areas.  This week, I’m looking at Visual Studio 2010 performance problems, and this gem with the keyboard in Visual Studio locking up ended up catching my attention. First of all, here’s a link to one of the many Connect bugs describing the problem: Microsoft Connect I like this problem because it really highlights the challenges of reproducing customer bugs.  There aren’t any clear steps provided here, and I don’t know a lot about your environment: not just the basics like our OS version, but also what third party plug-ins or antivirus software you might be running that might contribute to the problem.  In this case, my gut tells me that there is more than one bug here, just by the sheer volume of reports.  Here’s another thread where users talk about it: Microsoft Connect The volume and different configurations are staggering.  From a customer perspective, this is a very clear cut case of basic functionality not working in the product, but from our perspective, it’s hard to find something reproducible: even customers don’t quite agree on what causes the problem (installing ReSharper seems to cause a problem…or does it?). So this then, is the start of a QA investigation. If anybody has isolated repro steps (just comment on this post) that they can provide this will immensely help us nail down the issue(s), but I’ll be doing a multi-part series on my progress and methodologies as I look into the problem.

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  • Keyboard locking up in Visual Studio 2010, Part 2

    - by Jim Wang
    Last week I posted about looking into the keyboard locking up issue in Visual Studio.  So far it looks like not a lot of people have replied to provide concrete repro steps, which confirms my suspicion that this is somewhat of a random issue. So at this point, I have a couple of choices.  I can either wait for somebody in the community to provide a repro of the problem that I can reliably run into, or I can do the work myself. I’m going to do both, so while I’m waiting for more possible bug reports, I’m going to write a tool that models the behavior of a typical Visual Studio user and use that to hopefully isolate the problem. I’ve chosen to go with this path since given the information in the bug reports, it seems people hit the issue with many different configurations in many different scenarios.  This means that me sitting down without any solid repro steps is likely not going to be a good use of time.  Instead, I’m going to go with a model-based testing approach where I will define a series of actions that a user in VS can do, and then proceed to run my model.  I’ll let you guys know how this works out for isolating bugs :) I’m using an internal tool for the model engine and AutoIt for the UI automation (I want something lightweight for a one-off).  One of the challenges will be getting feedback: AutoIt is great at driving, but not so great at understanding what success and failure means.

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  • PHP file_put_contents File Locking

    - by hozza
    The Senario: You have a file with a string (average sentence worth) on each line. For arguments sake lets say this file is 1Mb in size (thousands of lines). You have a script that reads the file, changes some of the strings within the document (not just appending but also removing and modifying some lines) and then overwrites all the data with the new data. The Questions: Does 'the server' PHP, OS or httpd etc. already have systems in place to stop issues like this (reading/writing half way through a write)? i. If it does, please explain how it works and give examples or links to relevant documentation. ii. If not, are there things I can enable or set-up, such as locking a file until a write is completed and making all other reads and/or writes fail until the previous script has finished writing? My Assumptions and Other Information: The server in question is running PHP and Apache or Lighttpd. If the script is called by one user and is halfway through writing to the file and another user reads the file at that exact moment. The user who reads it will not get the full document, as it hasn't been written yet. (If this assumption is wrong please correct me) I'm only concerned with PHP writing and reading to a text file, and in particular, the functions "fopen"/"fwrite" and mainly "file_put_contents". I have looked at the "file_put_contents" documentation but have not found the level of detail or a good explanation of what the "LOCK_EX" flag is or does. The senario is an EXAMPLE of a worst case senario where I would assume these issues are more likely to occur, due to the large size of the file and the way the data is edited. I want to learn more about these issues and don't want or need answers or comments such as "use mysql" or "why are you doing that" because I'm not doing that, I just want to learn about file read/writing with PHP and don't seem to be looking in the right places/documentation and yes I understand PHP is not the perfect language for working with files in this way...

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  • Optimistic non-locking copy of InnoDB .frm files

    - by jothir
    MySQL Enterprise Backup(MEB) does hot backup of innodb data and log files. Till MEB 3.6.1, the user backs up the only innodb tables in a 3 step process: STEP 1. Take backup using --only-innodb option STEP 2. Temporarily make the table read only by executing “FLUSH TABLES WITH READ LOCK” MEB 3.7.0 has an enhancement to innodb file copying. The .frm files gets copied along with the hot backup done for innodb files. I would like to make the blog a little interactive by explaining the feature as answers: 1. What are these .frm files? The files containing the metadata, such as the table definition, of a MySQL table. For backups, the full set of .frm files are always required along with the backup data, to be able to restore tables that are altered or dropped after the backup. 2. Can the .frm files not be copied by MEB itself? --only-innodb-with-frm is the new option introduced in MEB 3.7.1 to do a copy of .frm files without locking the tables during backup operation itself. This is to reduce the pain of manually copying the .frm files. The option is intended for backups where you can ensure that no ALTER TABLE, CREATE TABLE, DROP TABLE, or other DDL statements modify the .frm files for InnoDB tables during the backup operation. 3. How is data consistency ensured? MEB does validation of the .frm files after copying by comparing with the server directory to see if the timestamps of any of the .frm files is greater than the saved system time (check .frm time).  This change in timestamp of the .frm files will show if a table is altered during the process of backup. The total number of frm files in the server directory is also verified against the copied contents. If the number of .frm files is less compared to server directory, it shows that table/tables have been dropped during the process of backup. If the number of .frm files is more compared to server directory, it shows that new table/tables have been created during backup operation. 4. How does MEB handle data inconsistency? MEB copies the .frm files through several iterations,  does the validation and throws a WARNING if there is any inconsistency found in .frm files at the end of backup operation. This means the user is warned of some DDL operations that had occurred during backup operation, and has to manually copy the .frm files or do a backup again. 5. What is the option and explain its usage? The option introduced is --only-innodb-with-frm which does optimistic copy of .frm files without locking. This can be used when the user wants to backup only innodb tables along with .frm files. The option can take one of the 2 values: all | related. --only-innodb-with-frm=all does copy of all .frm files of all innodb tables. --only-innodb-with-frm=related works in conjunction with --include option.This is to allow partial backup of .frm files corresponding to the tables specified in --include. Let me show the usage with example output: ./mysqlbackup -uroot --backup-dir=/logs/backupWithFrmAll --only-innodb-with-frm=all backup MySQL Enterprise Backup version 3.7.1 [2012/06/05] Copyright (c) 2003, 2012, Oracle and/or its affiliates. All Rights Reserved. INFO: Starting with following command line ... ./mysqlbackup -uroot --backup-dir=/logs/backupWithFrmAll        --only-innodb-with-frm=all backup INFO: Got some server configuration information from running server. IMPORTANT: Please check that mysqlbackup run completes successfully.            At the end of a successful 'backup' run mysqlbackup            prints "mysqlbackup completed OK!". --------------------------------------------------------------------                       Server Repository Options: --------------------------------------------------------------------  datadir                          =  /mysql/trydb/  innodb_data_home_dir             =    innodb_data_file_path            =  ibdata1:10M:autoextend  innodb_log_group_home_dir        =  /mysql/trydb/  innodb_log_files_in_group        =  2  innodb_log_file_size             =  5242880 --------------------------------------------------------------------                       Backup Config Options: --------------------------------------------------------------------  datadir                          =  /logs/backupWithFrmAll/datadir  innodb_data_home_dir             =  /logs/backupWithFrmAll/datadir  innodb_data_file_path            =  ibdata1:10M:autoextend  innodb_log_group_home_dir        =  /logs/backupWithFrmAll/datadir  innodb_log_files_in_group        =  2  innodb_log_file_size             =  5242880 mysqlbackup: INFO: Unique generated backup id for this is 13451979804504860 mysqlbackup: INFO: Uses posix_fadvise() for performance optimization. mysqlbackup: INFO: System tablespace file format is Antelope. mysqlbackup: INFO: Found checkpoint at lsn 1656792. mysqlbackup: INFO: Starting log scan from lsn 1656320. 120817 15:36:22 mysqlbackup: INFO: Copying log... 120817 15:36:22 mysqlbackup: INFO: Log copied, lsn 1656792.          We wait 1 second before starting copying the data files... 120817 15:36:23 mysqlbackup: INFO: Copying /mysql/trydb/ibdata1 (Antelope file format). 120817 15:36:23 mysqlbackup: INFO: Copying /mysql/trydb/innodb1/table2.ibd (Antelope file format). 120817 15:36:23 mysqlbackup: INFO: Copying /mysql/trydb/innodb1/table3.ibd (Antelope file format). 120817 15:36:23 mysqlbackup: INFO: Copying /mysql/trydb/innodb1/table1.ibd (Antelope file format). mysqlbackup: INFO: Opening backup source directory '/mysql/trydb/' 120817 15:36:23 mysqlbackup: INFO: Starting to backup .frm files in the subdirectories of /mysql/trydb/ mysqlbackup: INFO: Copying innodb data and logs during final stage ... mysqlbackup: INFO: A copied database page was modified at 1656792.          (This is the highest lsn found on page)          Scanned log up to lsn 1656792.          Was able to parse the log up to lsn 1656792.          Maximum page number for a log record 0 mysqlbackup: INFO: Copying non-innodb files took 2.000 seconds 120817 15:36:25 mysqlbackup: INFO: Full backup completed! mysqlbackup: INFO: Backup created in directory '/logs/backupWithFrmAll' -------------------------------------------------------------   Parameters Summary          -------------------------------------------------------------   Start LSN                  : 1656320   End LSN                    : 1656792 ------------------------------------------------------------- mysqlbackup completed OK! bash$ ls /logs/backupWithFrmAll/datadir/innodb1/ table1.frm  table1.ibd  table2.frm  table2.ibd  table3.frm  table3.ibd Here the backup directory contains all the .frm files of all the innodb tables. ./mysqlbackup -uroot --backup-dir=/logs/backupWithFrm --include="innodb1.table3.*" --only-innodb-with-frm=related backup MySQL Enterprise Backup version 3.7.1 [2012/06/05] Copyright (c) 2003, 2012, Oracle and/or its affiliates. All Rights Reserved. INFO: Starting with following command line ... ./mysqlbackup -uroot --backup-dir=/logs/backup371frm        --include=innodb1.table3.* --only-innodb-with-frm=related backup INFO: Got some server configuration information from running server. IMPORTANT: Please check that mysqlbackup run completes successfully.            At the end of a successful 'backup' run mysqlbackup            prints "mysqlbackup completed OK!". --------------------------------------------------------------------                       Server Repository Options: --------------------------------------------------------------------  datadir                          = /mysql/trydb/  innodb_data_home_dir             =    innodb_data_file_path            =  ibdata1:10M:autoextend  innodb_log_group_home_dir        =  /mysql/trydb  innodb_log_files_in_group        =  2  innodb_log_file_size             =  5242880 --------------------------------------------------------------------                       Backup Config Options: --------------------------------------------------------------------  datadir                          =  /logs/backupWithFrm/datadir  innodb_data_home_dir             =  /logs/backupWithFrm/datadir  innodb_data_file_path            =  ibdata1:10M:autoextend  innodb_log_group_home_dir        =  /logs/backupWithFrm/datadir  innodb_log_files_in_group        =  2  innodb_log_file_size             =  5242880 mysqlbackup: INFO: Unique generated backup id for this is 13451973458118162 mysqlbackup: INFO: Uses posix_fadvise() for performance optimization. mysqlbackup: INFO: The --include option specified: innodb1.table3.* mysqlbackup: INFO: System tablespace file format is Antelope. mysqlbackup: INFO: Found checkpoint at lsn 1656792. mysqlbackup: INFO: Starting log scan from lsn 1656320. 120817 15:25:47 mysqlbackup: INFO: Copying log... 120817 15:25:47 mysqlbackup: INFO: Log copied, lsn 1656792.          We wait 1 second before starting copying the data files... 120817 15:25:48 mysqlbackup: INFO: Copying /mysql/trydbibdata1 (Antelope file format). 120817 15:25:49 mysqlbackup: INFO: Copying /mysql/trydbinnodb1/table3.ibd (Antelope file format). mysqlbackup: INFO: Opening backup source directory '/mysql/trydb' 120817 15:25:49 mysqlbackup: INFO: Starting to backup .frm files in the subdirectories of /mysql/trydb mysqlbackup: INFO: Copying innodb data and logs during final stage ... mysqlbackup: INFO: A copied database page was modified at 1656792.          (This is the highest lsn found on page)          Scanned log up to lsn 1656792.          Was able to parse the log up to lsn 1656792.          Maximum page number for a log record 0 mysqlbackup: INFO: Copying non-innodb files took 2.000 seconds 120817 15:25:51 mysqlbackup: INFO: Full backup completed! mysqlbackup: INFO: Backup created in directory '/logs/backupWithFrm' -------------------------------------------------------------   Parameters Summary          -------------------------------------------------------------   Start LSN                  : 1656320   End LSN                    : 1656792 ------------------------------------------------------------- mysqlbackup completed OK! bash$ ls /logs/backupWithFrm/datadir/innodb1/ table3.frm table3.ibd Thus the backup directory contains only the .frm file matching the innodb table name specified in --include option. In a nutshell, we present our great new option --only-innodb-with-frm which is a true hot InnoDB-only backup with .frm files, but with an additional check, if any DDL happened during the backup. If a DDL has happened, the DBA can decide if to repeat the backup, or to live with the potential inconsistency. This is the ideal solution for users that have all their "real" data in InnoDB and seldom change their schemas. You may also like: http://dev.mysql.com/doc/mysql-enterprise-backup/3.7/en/backup-partial-options.html   STEP 3. Manually copy the .frm files of innodb tables to the destination directory where backup is stored.

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  • PPPD Is Locking the Modem and Not Releasing It

    - by Skid
    Got an issue with PPPD on one of our system, we have a PC that is used to talk to remote sites via a dial up connection, the modem can both connect out to the sites and the sites also dial back in. Currently I'm having an issue where some times a site ether dials in or we dial out, and it connects, but then blocks the modem and throws and error to kern.log. Aug 26 14:23:57 TM-SCADA kernel: [191233.503745] INFO: task pppd:8142 blocked for more than 120 seconds. Aug 26 14:23:57 TM-SCADA kernel: [191233.503750] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Aug 26 14:23:57 TM-SCADA kernel: [191233.503753] pppd D ffffffff8180cb40 0 8142 1 0x00000000 Aug 26 14:23:57 TM-SCADA kernel: [191233.503759] ffff8800ac1f5dc8 0000000000000086 ffff8800ac1f5fd8 00000000000137c0 Aug 26 14:23:57 TM-SCADA kernel: [191233.503765] ffff8800ac1f4010 00000000000137c0 00000000000137c0 00000000000137c0 Aug 26 14:23:57 TM-SCADA kernel: [191233.503770] ffff8800ac1f5fd8 00000000000137c0 ffffffff81c13020 ffff880135df5b80 Aug 26 14:23:57 TM-SCADA kernel: [191233.503775] Call Trace: Aug 26 14:23:57 TM-SCADA kernel: [191233.503784] [<ffffffff8166ba29>] schedule+0x29/0x70 Aug 26 14:23:57 TM-SCADA kernel: [191233.503790] [<ffffffff813db005>] tty_ldisc_ref_wait+0x65/0xb0 Aug 26 14:23:57 TM-SCADA kernel: [191233.503796] [<ffffffff813f3061>] ? uart_ioctl+0xd1/0x1c0 Aug 26 14:23:57 TM-SCADA kernel: [191233.503801] [<ffffffff81076960>] ? wake_up_bit+0x40/0x40 Aug 26 14:23:57 TM-SCADA kernel: [191233.503806] [<ffffffff813d3fa0>] tty_ioctl+0x2c0/0x9a0 Aug 26 14:23:57 TM-SCADA kernel: [191233.503810] [<ffffffff811d0549>] ? fcntl_setlk+0x69/0x200 Aug 26 14:23:57 TM-SCADA kernel: [191233.503815] [<ffffffff81195f79>] do_vfs_ioctl+0x99/0x330 Aug 26 14:23:57 TM-SCADA kernel: [191233.503820] [<ffffffff81195212>] ? do_fcntl+0x232/0x410 Aug 26 14:23:57 TM-SCADA kernel: [191233.503823] [<ffffffff811962b1>] sys_ioctl+0xa1/0xb0 Aug 26 14:23:57 TM-SCADA kernel: [191233.503829] [<ffffffff81674e69>] system_call_fastpath+0x16/0x1b The syslog trace stops at "Serial connection established". Aug 28 06:00:03 TM-SCADA pppd[10358]: pppd 2.4.5 started by root, uid 0 Aug 28 06:00:04 TM-SCADA chat[10360]: abort on (NO CARRIER) Aug 28 06:00:04 TM-SCADA chat[10360]: abort on (NO DIALTONE) Aug 28 06:00:04 TM-SCADA chat[10360]: abort on (ERROR) Aug 28 06:00:04 TM-SCADA chat[10360]: abort on (NO ANSWER) Aug 28 06:00:04 TM-SCADA chat[10360]: abort on (BUSY) Aug 28 06:00:04 TM-SCADA chat[10360]: abort on (Username/Password Incorrect) Aug 28 06:00:04 TM-SCADA chat[10360]: send (atz^M) Aug 28 06:00:04 TM-SCADA chat[10360]: expect (OK) Aug 28 06:00:04 TM-SCADA chat[10360]: atz^M^M Aug 28 06:00:04 TM-SCADA chat[10360]: OK Aug 28 06:00:04 TM-SCADA chat[10360]: -- got it Aug 28 06:00:04 TM-SCADA chat[10360]: send (atx0^M) Aug 28 06:00:04 TM-SCADA chat[10360]: expect (OK) Aug 28 06:00:04 TM-SCADA chat[10360]: ^M Aug 28 06:00:04 TM-SCADA chat[10360]: atx0^M^M Aug 28 06:00:04 TM-SCADA chat[10360]: OK Aug 28 06:00:04 TM-SCADA chat[10360]: -- got it Aug 28 06:00:04 TM-SCADA chat[10360]: send (atdt0123456789^M) Aug 28 06:00:04 TM-SCADA chat[10360]: expect (CONNECT/ARQ) Aug 28 06:00:04 TM-SCADA chat[10360]: ^M Aug 28 06:00:30 TM-SCADA chat[10360]: atdt0123456789^M^M Aug 28 06:00:30 TM-SCADA chat[10360]: CONNECT/ARQ Aug 28 06:00:30 TM-SCADA chat[10360]: -- got it Aug 28 06:00:30 TM-SCADA pppd[10358]: Serial connection established. I've only found two ways to release the modem in this condition, the first is to turn the modem off and on again, the second is to delete the serial lock file, and then SIGKILL pppd. Now I could write into our software to do the latter if the modem is locked, but I would rather stop it from locking in the first place if at all possible. The reason I put this issue in the askubuntu is because we used to use OpenSuse and never had an issue with it, admittedly that was version 11.2 or earlier so its still and old kernel, but I figured I would ask here first anyway. Any suggestions of places to look would be appreciated.

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  • Why avoid pessimistic locking in a version control system?

    - by raven
    Based on a few posts I've read concerning version control, it seems people think pessimistic locking in a version control system is a bad thing. Why? I understand that it prevents one developer from submitting a change while another has the file checked out, but so what? If your code files are so big that you constantly have more than one person working on them at the same time, I submit that you should reorganize your code. Break it up into smaller functional units. Integration of concurrent code changes is a tedious and error-prone process even with the tools a good version control system provides to make it easier. I think it should be avoided if at all possible. So, why is pessimistic locking discouraged?

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  • How do I find out which process is locking a file using .NET?

    - by AJ
    I've seen several of answers about using Handle or Process Monitor, but I would like to be able to find out in my own code (C#) which process is locking a file. I have a nasty feeling that I'm going to have to spelunk around in the win32 API, but if anyone has already done this and can put me on the right track, I'd really appreciate the help. Update Links to similar questions How does one figure out what process locked a file using c#? Command line tool Across a Network Locking a USB device Unit test fails with locked file deleting locked file

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  • System locking up with suspicious messages about hard disk

    - by Chris Conway
    My system has started behaving strangely, intermittently locking up. I see messages like the following in syslog: Nov 18 22:22:00 claypool kernel: [ 3428.078156] ata3.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 Nov 18 22:22:00 claypool kernel: [ 3428.078163] ata3.00: irq_stat 0x40000000 Nov 18 22:22:00 claypool kernel: [ 3428.078167] sr 2:0:0:0: CDB: Test Unit Ready: 00 00 00 00 00 00 Nov 18 22:22:00 claypool kernel: [ 3428.078182] ata3.00: cmd a0/00:00:00:00:00/00:00:00:00:00/a0 tag 0 Nov 18 22:22:00 claypool kernel: [ 3428.078184] res 50/00:03:00:00:00/00:00:00:00:00/a0 Emask 0x1 (device error) Nov 18 22:22:00 claypool kernel: [ 3428.078188] ata3.00: status: { DRDY } Nov 18 22:22:00 claypool kernel: [ 3428.080887] ata3.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 Nov 18 22:22:00 claypool kernel: [ 3428.080890] ata3.00: irq_stat 0x40000000 Nov 18 22:22:00 claypool kernel: [ 3428.080893] sr 2:0:0:0: CDB: Test Unit Ready: 00 00 00 00 00 00 Nov 18 22:22:00 claypool kernel: [ 3428.080905] ata3.00: cmd a0/00:00:00:00:00/00:00:00:00:00/a0 tag 0 Nov 18 22:22:00 claypool kernel: [ 3428.080906] res 50/00:03:00:00:00/00:00:00:00:00/a0 Emask 0x1 (device error) Nov 18 22:22:00 claypool kernel: [ 3428.080910] ata3.00: status: { DRDY } And then this: Nov 18 23:13:56 claypool kernel: [ 6544.000798] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen Nov 18 23:13:56 claypool kernel: [ 6544.000804] ata1.00: failed command: FLUSH CACHE EXT Nov 18 23:13:56 claypool kernel: [ 6544.000814] ata1.00: cmd ea/00:00:00:00:00/00:00:00:00:00/a0 tag 0 Nov 18 23:13:56 claypool kernel: [ 6544.000815] res 40/00:00:00:4f:c2/00:00:00:00:00/40 Emask 0x4 (timeout) Nov 18 23:13:56 claypool kernel: [ 6544.000819] ata1.00: status: { DRDY } Nov 18 23:13:56 claypool kernel: [ 6544.000825] ata1: hard resetting link Nov 18 23:14:01 claypool kernel: [ 6549.360324] ata1: link is slow to respond, please be patient (ready=0) Nov 18 23:14:06 claypool kernel: [ 6554.008091] ata1: COMRESET failed (errno=-16) Nov 18 23:14:06 claypool kernel: [ 6554.008103] ata1: hard resetting link Nov 18 23:14:11 claypool kernel: [ 6559.372246] ata1: link is slow to respond, please be patient (ready=0) Nov 18 23:14:16 claypool kernel: [ 6564.020228] ata1: COMRESET failed (errno=-16) Nov 18 23:14:16 claypool kernel: [ 6564.020235] ata1: hard resetting link Nov 18 23:14:21 claypool kernel: [ 6569.380109] ata1: link is slow to respond, please be patient (ready=0) Nov 18 23:14:31 claypool kernel: [ 6579.460243] ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300) Nov 18 23:14:31 claypool kernel: [ 6579.486595] ata1.00: configured for UDMA/133 Nov 18 23:14:31 claypool kernel: [ 6579.486601] ata1.00: retrying FLUSH 0xea Emask 0x4 Nov 18 23:14:31 claypool kernel: [ 6579.486939] ata1.00: device reported invalid CHS sector 0 Nov 18 23:14:31 claypool kernel: [ 6579.486952] ata1: EH complete Nov 18 23:17:01 claypool CRON[3910]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly) Nov 18 23:17:01 claypool CRON[3908]: (CRON) error (grandchild #3910 failed with exit status 1) Nov 18 23:17:01 claypool postfix/sendmail[3925]: fatal: open /etc/postfix/main.cf: No such file or directory Nov 18 23:17:01 claypool CRON[3908]: (root) MAIL (mailed 1 byte of output; but got status 0x004b, #012) Nov 18 23:39:01 claypool CRON[4200]: (root) CMD ( [ -x /usr/lib/php5/maxlifetime ] && [ -d /var/lib/php5 ] && find /var/lib/php5/ -type f -cmin +$(/usr/lib/php5/maxlifetime) -print0 | xargs -n 200 -r -0 rm) There are no messages marked after 23:39. When I next tried to use the machine, it would not return from the screensaver (blank screen), nor switch to another terminal, and I had to hard reboot it. [UPDATE] The output of smartctl is here. I had trouble getting this, because / is being mounted read-only (?!), which prevents most applications from running. Also, it may not be related, but I have the following worrying messages in dmesg: [ 10.084596] k8temp 0000:00:18.3: Temperature readouts might be wrong - check erratum #141 [ 10.098477] i2c i2c-0: nForce2 SMBus adapter at 0x600 [ 10.098483] ACPI: resource nForce2_smbus [io 0x0700-0x073f] conflicts with ACPI region SM00 [??? 0x00000700-0x0000073f flags 0x30] [ 10.098486] ACPI: This conflict may cause random problems and system instability [ 10.098487] ACPI: If an ACPI driver is available for this device, you should use it instead of the native driver [ 10.098509] i2c i2c-1: nForce2 SMBus adapter at 0x700 [ 10.112570] Linux agpgart interface v0.103 [ 10.155329] atk: Resources not safely usable due to acpi_enforce_resources kernel parameter [ 10.161506] it87: Found IT8712F chip at 0x290, revision 8 [ 10.161517] it87: VID is disabled (pins used for GPIO) [ 10.161527] it87: in3 is VCC (+5V) [ 10.161528] it87: in7 is VCCH (+5V Stand-By) [ 10.161560] ACPI: resource it87 [io 0x0295-0x0296] conflicts with ACPI region ECRE [??? 0x00000290-0x000002af flags 0x45] [ 10.161562] ACPI: This conflict may cause random problems and system instability [ 10.161564] ACPI: If an ACPI driver is available for this device, you should use it instead of the native driver [UPDATE 2] I swapped in a new SATA cable, per Phil's suggestion. The current output of smartctl is here, if it helps. [UPDATE 3] I don't think the cable fixed it. The system hasn't locked up yet, but my media player crashed a few minutes ago and I have the following in the syslog: Nov 20 16:07:17 claypool kernel: [ 2294.400033] ata1: link is slow to respond, please be patient (ready=0) Nov 20 16:07:47 claypool kernel: [ 2324.084581] ata1: COMRESET failed (errno=-16) Nov 20 16:07:47 claypool kernel: [ 2324.084588] ata1: limiting SATA link speed to 1.5 Gbps Nov 20 16:07:47 claypool kernel: [ 2324.084592] ata1: hard resetting link I get the following response from smartctl: $ sudo smartctl -a /dev/sda [sudo] password for chris: sudo: Can't open /var/lib/sudo/chris/0: Read-only file system smartctl 5.40 2010-03-16 r3077 [i686-pc-linux-gnu] (local build) Copyright (C) 2002-10 by Bruce Allen, http://smartmontools.sourceforge.net Device: /0:0:0:0 Version: scsiModePageOffset: response length too short, resp_len=47 offset=50 bd_len=46 >> Terminate command early due to bad response to IEC mode page A mandatory SMART command failed: exiting. To continue, add one or more '-T permissive' options.

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  • How to get the Jabber ID for a Multi User Chat nick

    - by Kutzi
    I'm trying to get the Jabber ID for a nick in a multi user chat, but the following code returns only null: class JabberMUCMessageListenerAdapter implements PacketListener { private final MultiUserChat muc; public JabberMUCMessageListenerAdapter(MultiUserChat muc) { this.muc = muc; } @Override public void processPacket(Packet p) { if (p instanceof Message) { final Message msg = (Message) p; String jid = muc.getOccupant(msg.getFrom()).getJid(); // returns null ... } } } Does anyone know, what I'm doing wrong?

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  • locking on dictionary of structs not working between 2 threads?

    - by Rancur3p1c
    C#, .Net2.0, XP, Zen I have 2 threads accessing a shared dictionary of structures, each thread via an event. At the beginning of the event I lock the dictionary, remove some structures, and exit the lock+event. Yet somehow the 2nd thread|event is finding some of the removed structures. Conceptually I must be doing something wrong for this to be happening? I thought locking was supposed to make it thread safe?

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  • T-SQL Tuesday #006: LOB, row-overflow and locking behavior

    - by Michael Zilberstein
    This post is my contribution to T-SQL Tuesday #006 , hosted this time by Michael Coles . Actually this post was born last Thursday when I attended Kalen Delaney's "Deep dive into SQL Server Internals" seminar in Tel-Aviv. I asked question, Kalen didn't have answer at hand, so during a break I created demo in order to check certain behavior. Demo goes later in this post but first small teaser. I have MyTable table with 10 rows. I take 2 rows that reside on different pages. In first session...(read more)

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  • Advantages of Locking Laptop Cases

    A laptop is meant to be carried around from one place to another and should be never let out of sight when being away from home but this is unfortunately not always possible. "Many of us store valu... [Author: Jeremy Mezzi - Computers and Internet - May 29, 2010]

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  • Google locking on Ubuntu

    - by user170534
    Problem I'm facing is that Google doesn't respond well timed to connection requests send from any browsers known to Linux. As far as I can tell, this was existent in Mint, which is Ubuntu based. I have no debug or guess about cause but I'm sure there are people with the same problem. ping of terminal is untouched but any other browser keeps unloaded, for example; google loads fine, I search for something. Then I decide to search for something else and ta daa: You gotta wait for 30 seconds for Google server to respond. I tried using google's public DNS without success. Flare the suggestions & ideas!?

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  • Ubuntu 12.04 not Locking Encrypted Hard Drive on Log Out

    - by J.L.
    I'm running Ubuntu 12.04 with Gnome 3.4. I have two external hard drives. I encrypted both using Ubuntu's Disk Utility. When I use Nautilus to mount them, I'm asked for my decryption password. Regardless of whether I then click "Forget password immediately" or "Remember password until you logout", though, I find that Ubuntu does not lock the drives when I log out. Rather, when I log back in, they're still mounted. (To be clear, restarting the computer does unmount them so that they require the password on the next log in.) I'm concerned that these drives are remaining unprotected when I log out without restarting my computer. I would be grateful for help understanding whether this is a bug. Thank you!

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  • Automatically locking screen without shutting it off

    - by milkandtang
    Hey everyone— I have a home theater PC running Ubuntu 11.10, outputting over HDMI (for audio and video). I'm having an issue: I'd like the screen to lock automatically (when video is not playing, of course) but do not want the screen to turn off automatically, because that kills audio. I can manually lock the screen, of course, but it appears that if you set the "Turn off screen" setting to "never", the screen will never lock, no matter what the "lock screen" timeout is set to. Is there a way to do what I'm asking, or will I have to install xscreensaver?

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