9 Commits (cff60f2dfa470d5736a19d36eb910844e31db764)

Author	SHA1	Message	Date
Heikki Linnakangas	89fd72cbf2	Introduce a pipe between postmaster and each backend, which can be used to ... detect postmaster death. Postmaster keeps the write-end of the pipe open, so when it dies, children get EOF in the read-end. That can conveniently be waited for in select(), which allows eliminating some of the polling loops that check for postmaster death. This patch doesn't yet change all the loops to use the new mechanism, expect a follow-on patch to do that. This changes the interface to WaitLatch, so that it takes as argument a bitmask of events that it waits for. Possible events are latch set, timeout, postmaster death, and socket becoming readable or writeable. The pipe method behaves slightly differently from the kill() method previously used in PostmasterIsAlive() in the case that postmaster has died, but its parent has not yet read its exit code with waitpid(). The pipe returns EOF as soon as the process dies, but kill() continues to return true until waitpid() has been called (IOW while the process is a zombie). Because of that, change PostmasterIsAlive() to use the pipe too, otherwise WaitLatch() would return immediately with WL_POSTMASTER_DEATH, while PostmasterIsAlive() would claim it's still alive. That could easily lead to busy-waiting while postmaster is in zombie state. Peter Geoghegan with further changes by me, reviewed by Fujii Masao and Florian Pflug.	15 years ago
Bruce Momjian	bf50caf105	pgindent run before PG 9.1 beta 1.	15 years ago
Heikki Linnakangas	754baa21f7	Automatically terminate replication connections that are idle for more ... than replication_timeout (a new GUC) milliseconds. The TCP timeout is often too long, you want the master to notice a dead connection much sooner. People complained about that in 9.0 too, but with synchronous replication it's even more important to notice dead connections promptly. Fujii Masao and Heikki Linnakangas	15 years ago
Bruce Momjian	5d950e3b0c	Stamp copyrights for year 2011.	15 years ago
Magnus Hagander	9f2e211386	Remove cvs keywords from all files.	15 years ago
Heikki Linnakangas	236b6bc29e	Simplify Windows implementation of latches. There's no need to keep a ... dynamic pool of event handles, we can permanently assign one for each shared latch. Thanks to that, we no longer need a separate shared memory block for latches, and we don't need to know in advance how many shared latches there is, so you no longer need to remember to update NumSharedLatches when you introduce a new latch to the system.	15 years ago
Heikki Linnakangas	c1ba7db6c1	Add a comment noting that the owner_pid test in OwnLatch is just a sanity ... check, per request by Jeff Davis.	15 years ago
Heikki Linnakangas	262c71ab63	Add missing #includes, needed on some platforms. This should make ... the unixware buildfarm animals happy again.	15 years ago
Heikki Linnakangas	2746e5f21d	Introduce latches. A latch is a boolean variable, with the capability to ... wait until it is set. Latches can be used to reliably wait until a signal arrives, which is hard otherwise because signals don't interrupt select() on some platforms, and even when they do, there's race conditions. On Unix, latches use the so called self-pipe trick under the covers to implement the sleep until the latch is set, without race conditions. On Windows, Windows events are used. Use the new latch abstraction to sleep in walsender, so that as soon as a transaction finishes, walsender is woken up to immediately send the WAL to the standby. This reduces the latency between master and standby, which is good. Preliminary work by Fujii Masao. The latch implementation is by me, with helpful comments from many people.	15 years ago