database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-09-02 04:21:28 +03:00
Code Activity

From: Tom Lane <tgl@sss.pgh.pa.us>

Browse Source 
Making PQrequestCancel safe to call in a signal handler turned out to be
much easier than I feared.  So here are the diffs.

Some notes:
  * I modified the postmaster's packet "iodone" callback interface to allow
    the callback routine to return a continue-or-drop-connection return
    code; this was necessary to allow the connection to be closed after
    receiving a Cancel, rather than proceeding to launch a new backend...
    Being a neatnik, I also made the iodone proc have a typechecked
    parameter list.
  * I deleted all code I could find that had to do with OOB.
  * I made some edits to ensure that all signals mentioned in the code
    are referred to symbolically not by numbers ("SIGUSR2" not "2").
    I think Bruce may have already done at least some of the same edits;
    I hope that merging these patches is not too painful.
This commit is contained in:
Marc G. Fournier
1998-07-09 03:29:11 +00:00
parent 8bf61820f0
commit a0659e3e2c
20 changed files with 597 additions and 287 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
src/backend/commands/async.c
View File

@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/async.c,v 1.34 1998/06/27 04:53:29 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/async.c,v 1.35 1998/07/09 03:28:44 scrappy Exp $
*
*-------------------------------------------------------------------------
*/
@@ -21,11 +21,11 @@
* 2.a If the process is the same as the backend process that issued
* notification (we are notifying something that we are listening),
* signal the corresponding frontend over the comm channel.
* 2.b For all other listening processes, we send kill(2) to wake up
* 2.b For all other listening processes, we send kill(SIGUSR2) to wake up
* the listening backend.
* 3. Upon receiving a kill(2) signal from another backend process notifying
* that one of the relation that we are listening is being notified,
* we can be in either of two following states:
* 3. Upon receiving a kill(SIGUSR2) signal from another backend process
* notifying that one of the relation that we are listening is being
* notified, we can be in either of two following states:
* 3.a We are sleeping, wake up and signal our frontend.
* 3.b We are in middle of another transaction, wait until the end of
* of the current transaction and signal our frontend.
@@ -46,7 +46,7 @@
* (which takes place after commit) to all listeners on this relation.
*
* 3. Async. notification results in all backends listening on relation
* to be woken up, by a process signal kill(2), with name of relation
* to be woken up, by a process signal kill(SIGUSR2), with name of relation
* passed in shared memory.
*
* 4. Each backend notifies its respective frontend over the comm