我要问并回答这个问题，因为我花了很长时间才弄清楚，我希望答案一直在这里开始。
问题：一个长时间运行的unixODBC查询阻止来自同一个应用程序的所有其他查询。
问题：如何阻止这种情况发生。
答案 0 :(得分：14)
答案，以__handles.c的剪切和粘贴评论的形式 - 我知道，为什么不是每个人都想在那里寻找文档，对吧？
/*
* use just one mutex for all the lists, this avoids any issues
* with deadlocks, the performance issue should be minimal, if it
* turns out to be a problem, we can readdress this
*
* We also have a mutex to protect the connection pooling code
*
* If compiled with thread support the DM allows four different
* thread strategies
*
* Level 0 - Only the DM internal structures are protected
* the driver is assumed to take care of it's self
*
* Level 1 - The driver is protected down to the statement level
* each statement will be protected, and the same for the connect
* level for connect functions, note that descriptors are considered
* equal to statements when it comes to thread protection.
*
* Level 2 - The driver is protected at the connection level. only
* one thread can be in a particular driver at one time
*
* Level 3 - The driver is protected at the env level, only one thing
* at a time.
*
* By default the driver open connections with a lock level of 3,
* this can be changed by adding the line
*
* Threading = N
*
* to the driver entry in odbcinst.ini, where N is the locking level
* (0-3)
*
*/
答案 1 :(得分：3)
只是对这个答案的补充。 unixODBC 2.3.0的当前版本默认为Threading = 0，因此现在默认假设驱动程序是线程安全的。这是过去几年的风险假设，而不是现在。
答案 2 :(得分：0)
如果您的驱动程序支持异步功能，则可以在异步模式下启用它并执行耗时的功能。
应用程序端不需要线程。