Re: [PATCH] OAuth: fix performance bug with stuck multiplexer events

[Jacob Champion]

Hi all,

On Thu, Jun 26, 2025 at 4:33 PM Jacob Champion
<jacob.champ...@enterprisedb.com> wrote:
> My plan, if this code seems reasonable, is to backport 0001-0003, but
> keep the larger 0004 on HEAD only until it has proven to be stable.
> It's a big new suite and I want to make sure it's not flapping on some
> buildfarm animal. Eventually I'll backport that too.

Any thoughts on the approach? Too big/too scary/too BSD-specific?

A small bit of self-review: a comment I wrote in the tests suggested
that the choice of readable/writable events was up to the multiplexer
implementation, but it *must* choose readable, due to the hardcoded
use of PGRES_POLLING_READING throughout the current code. Updated in
v2.

Thanks,
--Jacob

1:  ddb7875bb58 = 1:  379c12b5d26 oauth: Remove stale events from the kqueue 
multiplexer
2:  a871ce498ea = 2:  f30317d7265 oauth: Remove expired timers from the 
multiplexer
3:  5033b6d51c1 = 3:  d243d28964d oauth: Track total call count during a client 
flow
4:  f4a640f7995 ! 4:  ca6fd237653 oauth: Add unit tests for multiplexer handling
    @@ src/interfaces/libpq-oauth/test-oauth-curl.c (new)
     + *
     + * NB: our current multiplexer implementations (epoll/kqueue) are 
*readable*
     + * when the underlying libcurl sockets are *writable*. This behavior is 
pinned
    -+ * here to record that expectation, but it's not a required part of the 
API. If
    -+ * you've added a new implementation that doesn't have that behavior, 
feel free
    -+ * to modify this test.
    ++ * here to record that expectation; PGRES_POLLING_READING is hardcoded
    ++ * throughout the flow and would need to be changed if a new multiplexer 
does
    ++ * something different.
     + */
     +#define mux_is_ready(MUX, DEADLINE, TEST) \
     +  do { \

v2-0001-oauth-Remove-stale-events-from-the-kqueue-multipl.patch
Description: Binary data

v2-0002-oauth-Remove-expired-timers-from-the-multiplexer.patch
Description: Binary data

v2-0003-oauth-Track-total-call-count-during-a-client-flow.patch
Description: Binary data

v2-0004-oauth-Add-unit-tests-for-multiplexer-handling.patch
Description: Binary data