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Always use connections in non-blocking mode. 

Now that there's no blocking libpq callers left, default to using
non-blocking mode in connection_management.c.  This has two
advantages:
1) Blockiness doesn't have to frequently be reset, simplifying code
2) Prevents accidental use of blocking libpq functions, since they'll
   frequently return 'need IO'
pull/1473/head
Andres Freund 2017-06-30 18:20:54 -07:00
parent 90a2d13a64
commit 75a7ddea0d
2 changed files with 16 additions and 44 deletions
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7
src/backend/distributed/connection/connection_management.c
View File

@ -640,6 +640,13 @@ StartConnectionEstablishment(ConnectionHashKey *key)
connection->pgConn = PQconnectStartParams(keywords, values, false);
connection->connectionStart = GetCurrentTimestamp();
/*
* To avoid issues with interrupts not getting caught all our connections
* are managed in a non-blocking manner. remote_commands.c provides
* wrappers emulating blocking behaviour.
*/
PQsetnonblocking(connection->pgConn, true);
return connection;
}

53
src/backend/distributed/connection/remote_commands.c
View File

@ -280,7 +280,6 @@ SendRemoteCommandParams(MultiConnection *connection, const char *command,
const char *const *parameterValues)
{
PGconn *pgConn = connection->pgConn;
bool wasNonblocking = false;
int rc = 0;
LogRemoteCommand(connection, command);
@ -294,23 +293,11 @@ SendRemoteCommandParams(MultiConnection *connection, const char *command,
return 0;
}
wasNonblocking = PQisnonblocking(pgConn);
/* make sure not to block anywhere */
if (!wasNonblocking)
{
PQsetnonblocking(pgConn, true);
}
Assert(PQisnonblocking(pgConn));
rc = PQsendQueryParams(pgConn, command, parameterCount, parameterTypes,
parameterValues, NULL, NULL, 0);
/* reset nonblocking connection to its original state */
if (!wasNonblocking)
{
PQsetnonblocking(pgConn, false);
}
return rc;
}
@ -380,7 +367,6 @@ PGresult *
GetRemoteCommandResult(MultiConnection *connection, bool raiseInterrupts)
{
PGconn *pgConn = connection->pgConn;
bool wasNonblocking = false;
PGresult *result = NULL;
/*
@ -393,11 +379,6 @@ GetRemoteCommandResult(MultiConnection *connection, bool raiseInterrupts)
return PQgetResult(connection->pgConn);
}
wasNonblocking = PQisnonblocking(pgConn);
/* make sure not to block anywhere */
PQsetnonblocking(pgConn, true);
if (!FinishConnectionIO(connection, raiseInterrupts))
{
return NULL;
@ -408,8 +389,6 @@ GetRemoteCommandResult(MultiConnection *connection, bool raiseInterrupts)
result = PQgetResult(connection->pgConn);
PQsetnonblocking(pgConn, wasNonblocking);
return result;
}
@ -424,38 +403,31 @@ bool
PutRemoteCopyData(MultiConnection *connection, const char *buffer, int nbytes)
{
PGconn *pgConn = connection->pgConn;
bool wasNonblocking = false;
int copyState = 0;
bool success = false;
if (PQstatus(pgConn) != CONNECTION_OK)
{
return false;
}
wasNonblocking = PQisnonblocking(pgConn);
PQsetnonblocking(pgConn, true);
Assert(PQisnonblocking(pgConn));
copyState = PQputCopyData(pgConn, buffer, nbytes);
if (copyState == 1)
{
/* successful */
success = true;
return true;
}
else if (copyState == -1)
{
success = false;
return false;
}
else
{
bool allowInterrupts = true;
success = FinishConnectionIO(connection, allowInterrupts);
return FinishConnectionIO(connection, allowInterrupts);
}
PQsetnonblocking(pgConn, wasNonblocking);
return success;
}
@ -469,38 +441,31 @@ bool
PutRemoteCopyEnd(MultiConnection *connection, const char *errormsg)
{
PGconn *pgConn = connection->pgConn;
bool wasNonblocking = false;
int copyState = 0;
bool success = false;
if (PQstatus(pgConn) != CONNECTION_OK)
{
return false;
}
wasNonblocking = PQisnonblocking(pgConn);
PQsetnonblocking(pgConn, true);
Assert(PQisnonblocking(pgConn));
copyState = PQputCopyEnd(pgConn, errormsg);
if (copyState == 1)
{
/* successful */
success = true;
return true;
}
else if (copyState == -1)
{
success = false;
return false;
}
else
{
bool allowInterrupts = true;
success = FinishConnectionIO(connection, allowInterrupts);
return FinishConnectionIO(connection, allowInterrupts);
}
PQsetnonblocking(pgConn, wasNonblocking);
return success;
}