mirror/postgresql
2
0
Fork 0
mirror of https://git.postgresql.org/git/postgresql.git synced 2024-11-27 07:21:09 +08:00
Code Issues Packages Projects Releases Wiki Activity

Allow SIGINT to cancel psql database reconnections.

Browse Source 
After installing the SIGINT handler in psql, SIGINT can no longer cancel
database reconnections. For instance, if the user starts a reconnection
and then needs to do some form of interaction (ie psql is polling),
there is no way to cancel the reconnection process currently.

Use PQconnectStartParams() in order to insert a cancel_pressed check
into the polling loop.

Tristan Partin, reviewed by Gurjeet Singh, Heikki Linnakangas, Jelte
Fennema-Nio, and me.

Discussion: http://postgr.es/m/D08WWCPVHKHN.3QELIKZJ2D9RZ@neon.tech
This commit is contained in:
Robert Haas 2024-04-02 10:26:10 -04:00
parent f5e4dedfa8
commit cafe105655
1 changed files with 71 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

72
src/bin/psql/command.c
View File

@ -159,6 +159,7 @@ static void discard_query_text(PsqlScanState scan_state, ConditionalStack cstack
static bool copy_previous_query(PQExpBuffer query_buf, PQExpBuffer previous_buf);
static bool do_connect(enum trivalue reuse_previous_specification,
char *dbname, char *user, char *host, char *port);
static void wait_until_connected(PGconn *conn);
static bool do_edit(const char *filename_arg, PQExpBuffer query_buf,
int lineno, bool discard_on_quit, bool *edited);
static bool do_shell(const char *command);
@ -3595,11 +3596,12 @@ do_connect(enum trivalue reuse_previous_specification,
values[paramnum] = NULL;
/* Note we do not want libpq to re-expand the dbname parameter */
n_conn = PQconnectdbParams(keywords, values, false);
n_conn = PQconnectStartParams(keywords, values, false);
pg_free(keywords);
pg_free(values);
wait_until_connected(n_conn);
if (PQstatus(n_conn) == CONNECTION_OK)
break;
@ -3748,6 +3750,74 @@ do_connect(enum trivalue reuse_previous_specification,
return true;
}
/*
* Processes the connection sequence described by PQconnectStartParams(). Don't
* worry about reporting errors in this function. Our caller will check the
* connection's status, and report appropriately.
*/
static void
wait_until_connected(PGconn *conn)
{
bool forRead = false;
while (true)
{
int rc;
int sock;
time_t end_time;
/*
* On every iteration of the connection sequence, let's check if the
* user has requested a cancellation.
*/
if (cancel_pressed)
break;
/*
* Do not assume that the socket remains the same across
* PQconnectPoll() calls.
*/
sock = PQsocket(conn);
if (sock == -1)
break;
/*
* If the user sends SIGINT between the cancel_pressed check, and
* polling of the socket, it will not be recognized. Instead, we will
* just wait until the next step in the connection sequence or forever,
* which might require users to send SIGTERM or SIGQUIT.
*
* Some solutions would include the "self-pipe trick," using
* pselect(2) and ppoll(2), or using a timeout.
*
* The self-pipe trick requires a bit of code to setup. pselect(2) and
* ppoll(2) are not on all the platforms we support. The simplest
* solution happens to just be adding a timeout, so let's wait for 1
* second and check cancel_pressed again.
*/
end_time = time(NULL) + 1;
rc = PQsocketPoll(sock, forRead, !forRead, end_time);
if (rc == -1)
return;
switch (PQconnectPoll(conn))
{
case PGRES_POLLING_OK:
case PGRES_POLLING_FAILED:
return;
case PGRES_POLLING_READING:
forRead = true;
continue;
case PGRES_POLLING_WRITING:
forRead = false;
continue;
case PGRES_POLLING_ACTIVE:
pg_unreachable();
}
}
pg_unreachable();
}
void
connection_warnings(bool in_startup)