Dumb mistakes in WalSndWriteData()
Hi,
I^Wsomebody appears to have made a number of dumb mistakes in
WalSndWriteData(), namely:
1) The timestamp is set way too late, after
pq_putmessage_noblock(). That'll sometimes work, sometimes not. I
have no idea how that ended up happening. It's eye-wateringly dumb.
2) We only do WalSndKeepaliveIfNecessary() if we're blocked on socket
IO. But on a long-lived connection that might be a lot of data, we
should really do that once *before* trying to send the payload in the
first place.
3) Similarly to 2) it might be worthwhile checking for interrupts
everytime, not just when blocked on network IO.
Greetings,
Andres Freund
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On Mon, Oct 31, 2016 at 4:59 AM, Andres Freund <andres@anarazel.de> wrote:
I^Wsomebody appears to have made a number of dumb mistakes in
WalSndWriteData(), namely:
1) The timestamp is set way too late, after
pq_putmessage_noblock(). That'll sometimes work, sometimes not. I
have no idea how that ended up happening. It's eye-wateringly dumb.2) We only do WalSndKeepaliveIfNecessary() if we're blocked on socket
IO. But on a long-lived connection that might be a lot of data, we
should really do that once *before* trying to send the payload in the
first place.3) Similarly to 2) it might be worthwhile checking for interrupts
everytime, not just when blocked on network IO.
Do you intend to do something about these problems?
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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On 2016-10-31 09:44:16 -0400, Robert Haas wrote:
On Mon, Oct 31, 2016 at 4:59 AM, Andres Freund <andres@anarazel.de> wrote:
I^Wsomebody appears to have made a number of dumb mistakes in
WalSndWriteData(), namely:
1) The timestamp is set way too late, after
pq_putmessage_noblock(). That'll sometimes work, sometimes not. I
have no idea how that ended up happening. It's eye-wateringly dumb.2) We only do WalSndKeepaliveIfNecessary() if we're blocked on socket
IO. But on a long-lived connection that might be a lot of data, we
should really do that once *before* trying to send the payload in the
first place.3) Similarly to 2) it might be worthwhile checking for interrupts
everytime, not just when blocked on network IO.Do you intend to do something about these problems?
At least 1) and 2), yes. I basically wrote this email to have something
to reference in my todo list...
Greetings,
Andres Freund
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On Mon, Oct 31, 2016 at 10:54 PM, Andres Freund <andres@anarazel.de> wrote:
On 2016-10-31 09:44:16 -0400, Robert Haas wrote:
On Mon, Oct 31, 2016 at 4:59 AM, Andres Freund <andres@anarazel.de> wrote:
I^Wsomebody appears to have made a number of dumb mistakes in
WalSndWriteData(), namely:
1) The timestamp is set way too late, after
pq_putmessage_noblock(). That'll sometimes work, sometimes not. I
have no idea how that ended up happening. It's eye-wateringly dumb.2) We only do WalSndKeepaliveIfNecessary() if we're blocked on socket
IO. But on a long-lived connection that might be a lot of data, we
should really do that once *before* trying to send the payload in the
first place.3) Similarly to 2) it might be worthwhile checking for interrupts
everytime, not just when blocked on network IO.Do you intend to do something about these problems?
At least 1) and 2), yes. I basically wrote this email to have something
to reference in my todo list...
Just looking at this thread, 1) and 2) is actually something like the attached?
--
Michael