Re: [sqlite] is safe to use the same database connection at the same time in more than one thread?
1. tell my email client to add a copy of the sent message to the folder it belongs That is the most brilliant idea I've ever seen in my entire life.<< Forgive me for saying "how sad". Surely there must have been something more inspiring than an e-mail trick? Or maybe you are very young :) If you don't mind being patient all the list messages appear neatly sorted at the URL below in due course, and you'll see what has arrived as well as what has been sent: http://www.mail-archive.com/sqlite-users%40sqlite.org/ Michael Hooker On 10/11/2007 18:25:38, Don Lavelle ([EMAIL PROTECTED]) wrote: Hey, all. Thanks Gerry and Thomas for your replies. Now I know that my e-mails are being sent and are being received. This seems like a very knowledgeable and supportive mailing list. I'm really looking forward to participating. On Nov 10, 2007, at 11:18 AM, Thomas Fjellstrom wrote: > 1. tell my email client to add a copy of the sent message to the > folder it > belongs That is the most brilliant idea I've ever seen in my entire life. I will look into figuring it out with my mail client. Regards, Don - To unsubscribe, send email to [EMAIL PROTECTED] - - To unsubscribe, send email to [EMAIL PROTECTED] -
Re: [sqlite] is safe to use the same database connection at the same time in more than one thread?
Hey, all. Thanks Gerry and Thomas for your replies. Now I know that my e-mails are being sent and are being received. This seems like a very knowledgeable and supportive mailing list. I'm really looking forward to participating. On Nov 10, 2007, at 11:18 AM, Thomas Fjellstrom wrote: 1. tell my email client to add a copy of the sent message to the folder it belongs That is the most brilliant idea I've ever seen in my entire life. I will look into figuring it out with my mail client. Regards, Don - To unsubscribe, send email to [EMAIL PROTECTED] -
Re: [sqlite] is safe to use the same database connection at the same time in more than one thread?
Don Lavelle wrote: Hello, all, First, I apologize if the list has received multiple copies of e-mails from me. I'm using gmail, and gmail does strange things to e-mails when receiving through a POP client an e-mail that is from your own account. Your email made it to the list. I also have seen that gmail does not send to me a message I sent to the list. Looking into that is on my (long) list of things to do some day. Sorry I can't answer your SQLite question. Gerry PS You can look at one of the email archives (links at http://sqlite.org/support.html ) to see if a posted message was received. - To unsubscribe, send email to [EMAIL PROTECTED] -
Re: [sqlite] is safe to use the same database connection at the same time in more than one thread?
Hello, all, First, I apologize if the list has received multiple copies of e- mails from me. I'm using gmail, and gmail does strange things to e- mails when receiving through a POP client an e-mail that is from your own account. If anyone at all gets this, please reply to me personally, even if to say, "yes, I got your e-mail, even though your copy from the mailing list isn't getting to you." I don't mind my inbox being flooded ;-) I had tried to post a multi-threading question before, but 1) I never got the e-mail back (gmail is strange), and 2) I never saw a reply (perhaps the e-mail never got to you.) Second, my question is about SQLite and multi-threading. Basically, the snippet below means that if I have multiple threads executing SQL statements, and I want at least one thread to execute multiple SQL statements as a single unit, I need to make sure only one thread at a time is executing SQL, or the SQL statements that are outside of the thread may get lumped in with the transaction. As in, 10. thread 1: shut off auto commit 20. thread 1: SQL statement 1 succeeds 30. thread 2: independent SQL statement succeeds 40. thread 1: SQL statement 2 fails 50. thread 1: rollback, taking with it thread 2's effect If that's the case, it also answers my previous, unposted question about sqlite3_changes, which was, "what would sqlite3_changes return if it were called at line 35 in the above sequence?" Regards, Don Lavelle On Nov 8, 2007, at 9:23 AM, Salles, Joaquim Campos wrote: I found two e-mails (bellow) that I think give the answer: yes is safe to use the same database connection, but is not work in the way that I imagined. "Transaction control is per connection, not per thread." (Igor Tandetnik) or "That connection can then be used across threads, but it is for all intents and purposes a single line of communication with a database (using it twice at the same time doesn't somehow multiply that relationship)". (Stephan Beal) - To unsubscribe, send email to [EMAIL PROTECTED] -
RE: [sqlite] is safe to use the same database connection at the same time in more than one thread?
-Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: quinta-feira, 8 de novembro de 2007 12:04 To: sqlite-users@sqlite.org Subject: Re: [sqlite] is safe to use the same database connection at the same time in more than one thread? >Yes. The wiki page was correct when written but that was >prior to the release of version 3.5.0. OK. Maybe some upgrade the wiki release 3.5.*... >Note that SQLite uses mutexes internally so what will really >happen is one thread will block while the other is using the >database connection. Access to database connections is serialized. >But the application code does not need to concern itself with >the serialization any more. That is now handled automatically >by SQLite. Here is an important point: "Access to database connections is serialized". Thanks for the help. Joaquim - To unsubscribe, send email to [EMAIL PROTECTED] -
RE: [sqlite] is safe to use the same database connection at the same time in more than one thread?
-Original Message- >From: Salles, Joaquim Campos [mailto:[EMAIL PROTECTED] >Sent: quinta-feira, 8 de novembro de 2007 11:45 >To: sqlite-users@sqlite.org >Subject: [sqlite] is safe to use the same database connection at the same >time in more than one thread? >Is safe to use the same database connection at the same time in more >than one thread? Hello, I found two e-mails (bellow) that I think give the answer: yes is safe to use the same database connection, but is not work in the way that I imagined. "Transaction control is per connection, not per thread." (Igor Tandetnik) or "That connection can then be used across threads, but it is for all intents and purposes a single line of communication with a database (using it twice at the same time doesn't somehow multiply that relationship)". (Stephan Beal) My interpretation is correct? Probably is a good idea to review Multi Threading page (http://www.sqlite.org/cvstrac/wiki?p=MultiThreading) and alert about the characteristic :treath safe and Transaction control is per connection Best regards, Joaquim Reference: http://www.mail-archive.com/sqlite-users%40sqlite.org/msg28858.html You're confusing threads with the context of the connection. When you call sqlite3_open() you get a single connection to a db. That connection can then be used across threads, but it is for all intents and purposes a single line of communication with a database (using it twice at the same time doesn't somehow multiply that relationship). stephan beal http://www.mail-archive.com/sqlite-users%40sqlite.org/msg28868.html That would happen if thread B had its own, separate connection, but not when the two threads are working with the same connection. As far as SQLite is concerned, there's no difference between a single thread making two changes to the database within a single transaction, or two threads each making one change. Transaction control is per connection, not per thread. Igor Tandetnik - To unsubscribe, send email to [EMAIL PROTECTED] -
Re: [sqlite] is safe to use the same database connection at the same time in more than one thread?
"Salles, Joaquim Campos" <[EMAIL PROTECTED]> wrote: > Hello, > > Is safe to use the same database connection at the same time in more > than one thread? The bellow like that is safe: > > http://www.sqlite.org/34to35.html > > "Restrictions on the use of the same database connection by multiple > threads have been dropped. It is now safe for multiple threads to use > the same database connection at the same time." > > But in following URL say: > > http://www.sqlite.org/cvstrac/wiki?p=MultiThreading > > "Do not use the same database connection at the same time in more than > one thread." > > > So, for SQlite 3.5.* is safe to use the same database connection at the > same time in more than one thread? > Yes. The wiki page was correct when written but that was prior to the release of version 3.5.0. Note that SQLite uses mutexes internally so what will really happen is one thread will block while the other is using the database connection. Access to database connections is serialized. But the application code does not need to concern itself with the serialization any more. That is now handled automatically by SQLite. It is also my duty to earnestly warn programmers of all ilks that multi-threaded programming is madness. Multi-threading causes programs to run slower, have more bugs, and become harder to maintain. Threads are deadly. Avoid them. -- D. Richard Hipp <[EMAIL PROTECTED]> - To unsubscribe, send email to [EMAIL PROTECTED] -
[sqlite] is safe to use the same database connection at the same time in more than one thread?
Hello, Is safe to use the same database connection at the same time in more than one thread? The bellow like that is safe: http://www.sqlite.org/34to35.html "Restrictions on the use of the same database connection by multiple threads have been dropped. It is now safe for multiple threads to use the same database connection at the same time." But in following URL say: http://www.sqlite.org/cvstrac/wiki?p=MultiThreading "Do not use the same database connection at the same time in more than one thread." So, for SQlite 3.5.* is safe to use the same database connection at the same time in more than one thread? Thanks for the help, Best regards, Joaquim - To unsubscribe, send email to [EMAIL PROTECTED] -
