On 21/04/17 04:37, Petr Jelinek wrote:
> On 21/04/17 04:32, Craig Ringer wrote:
>> On 21 April 2017 at 10:20, Petr Jelinek <petr.jeli...@2ndquadrant.com> wrote:
>>> On 21/04/17 03:40, Andres Freund wrote:
>>>>
>>>> Since [1] walsender (not receiver as commit message says) can execute
>>>> SQL queries. While doing some testing of [2] I noticed that SQL queries
>>>> in walsender get stuck if parallelism is used - I have not investigated
>>>> why that is yet, but it surely is an issue. On first blush I'd suspect
>>>> that some signalling is not wired up correctly (cf. am_walsender branches
>>>> in PostgresMain() and such).
>>>
>>> Looks like SIGUSR1 being different is problem here - it's normally used
>>> to . I also noticed that we don't handle SIGINT (query cancel).
>>>
>>> I'll write proper patch but can you try to just use
>>> procsignal_sigusr1_handler for SIGUSR1 in walsender.c to see if it fixes
>>> the issue?
>>
>> That's what my recovery conflicts for logical decoding on standby
>> patch does, FWIW.
>>
>> I haven't found any issues yet..
>>
>
> Ah I knew I've seen that change somewhere. I thought it was either in my
> patch or master which is why I thought it's working fine already.
>
Here is patch. I changed both SIGINT and SIGUSR1 handlers, afaics it
does not break anything for existing walsender usage.
--
Petr Jelinek http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
From f59218135092bec9a64cf86b75f1f62a0271d448 Mon Sep 17 00:00:00 2001
From: Petr Jelinek <pjmo...@pjmodos.net>
Date: Fri, 21 Apr 2017 05:11:30 +0200
Subject: [PATCH] Handle signals correctly in walsender
Since we now support SQL queries in walsender, we also need to handle
SIGINT for query cancel and SIGUSR1 for IPC.
---
src/backend/replication/logical/launcher.c | 2 +-
src/backend/replication/walsender.c | 16 ++--------------
2 files changed, 3 insertions(+), 15 deletions(-)
diff --git a/src/backend/replication/logical/launcher.c
b/src/backend/replication/logical/launcher.c
index 761fbfa..e9dd886 100644
--- a/src/backend/replication/logical/launcher.c
+++ b/src/backend/replication/logical/launcher.c
@@ -254,7 +254,7 @@ logicalrep_worker_launch(Oid dbid, Oid subid, const char
*subname, Oid userid,
BackgroundWorker bgw;
BackgroundWorkerHandle *bgw_handle;
int i;
- int slot;
+ int slot = 0;
LogicalRepWorker *worker = NULL;
int nsyncworkers = 0;
TimestampTz now = GetCurrentTimestamp();
diff --git a/src/backend/replication/walsender.c
b/src/backend/replication/walsender.c
index b4ce75a..78369ae 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -212,7 +212,6 @@ static struct
/* Signal handlers */
static void WalSndSigHupHandler(SIGNAL_ARGS);
-static void WalSndXLogSendHandler(SIGNAL_ARGS);
static void WalSndLastCycleHandler(SIGNAL_ARGS);
/* Prototypes for private functions */
@@ -2830,17 +2829,6 @@ WalSndSigHupHandler(SIGNAL_ARGS)
errno = save_errno;
}
-/* SIGUSR1: set flag to send WAL records */
-static void
-WalSndXLogSendHandler(SIGNAL_ARGS)
-{
- int save_errno = errno;
-
- latch_sigusr1_handler();
-
- errno = save_errno;
-}
-
/* SIGUSR2: set flag to do a last cycle and shut down afterwards */
static void
WalSndLastCycleHandler(SIGNAL_ARGS)
@@ -2869,12 +2857,12 @@ WalSndSignals(void)
/* Set up signal handlers */
pqsignal(SIGHUP, WalSndSigHupHandler); /* set flag to read
config
* file */
- pqsignal(SIGINT, SIG_IGN); /* not used */
+ pqsignal(SIGINT, StatementCancelHandler); /* query cancel */
pqsignal(SIGTERM, die); /* request shutdown */
pqsignal(SIGQUIT, quickdie); /* hard crash time */
InitializeTimeouts(); /* establishes SIGALRM handler */
pqsignal(SIGPIPE, SIG_IGN);
- pqsignal(SIGUSR1, WalSndXLogSendHandler); /* request WAL sending
*/
+ pqsignal(SIGUSR1, procsignal_sigusr1_handler);
pqsignal(SIGUSR2, WalSndLastCycleHandler); /* request a last cycle
and
* shutdown */
--
2.7.4
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