105024a472
Commit f5e4dedfa exposed libpq's internal function PQsocketPoll without a lot of thought about whether that was an API we really wanted to chisel in stone. The main problem with it is the use of time_t to specify the timeout. While we do want an absolute time so that a loop around PQsocketPoll doesn't have problems with timeout slippage, time_t has only 1-second resolution. That's already problematic for libpq's own internal usage --- for example, pqConnectDBComplete has long had a kluge to treat "connect_timeout=1" as 2 seconds so that it doesn't accidentally round to nearly zero. And it's even less likely to be satisfactory for external callers. Hence, let's change this while we still can. The best idea seems to be to use an int64 count of microseconds since the epoch --- basically the same thing as the backend's TimestampTz, but let's use the standard Unix epoch (1970-01-01) since that's more likely for clients to be easy to calculate. Millisecond resolution would be plenty for foreseeable uses, but maybe the day will come that we're glad we used microseconds. Also, since time(2) isn't especially helpful for computing timeouts defined this way, introduce a new function PQgetCurrentTimeUSec to get the current time in this form. Remove the hack in pqConnectDBComplete, so that "connect_timeout=1" now means what you'd expect. We can also remove the "#include <time.h>" that f5e4dedfa added to libpq-fe.h, since there's no longer a need for time_t in that header. It seems better for v17 not to enlarge libpq-fe.h's include footprint from what it's historically been, anyway. I also failed to resist the temptation to do some wordsmithing on PQsocketPoll's documentation. Patch by me, per complaint from Dominique Devienne. Discussion: https://postgr.es/m/913559.1718055575@sss.pgh.pa.us
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
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