@ -355,7 +355,7 @@ do_sql_command(PGconn *conn, const char *sql)
res = PQexec ( conn , sql ) ;
if ( PQresultStatus ( res ) ! = PGRES_COMMAND_OK )
pgfdw_report_error ( ERROR , res , true , sql ) ;
pgfdw_report_error ( ERROR , res , conn , true , sql ) ;
PQclear ( res ) ;
}
@ -454,6 +454,7 @@ GetPrepStmtNumber(PGconn *conn)
*
* elevel : error level to use ( typically ERROR , but might be less )
* res : PGresult containing the error
* conn : connection we did the query on
* clear : if true , PQclear the result ( otherwise caller will handle it )
* sql : NULL , or text of remote command we tried to execute
*
@ -462,7 +463,8 @@ GetPrepStmtNumber(PGconn *conn)
* marked with have_error = true .
*/
void
pgfdw_report_error ( int elevel , PGresult * res , bool clear , const char * sql )
pgfdw_report_error ( int elevel , PGresult * res , PGconn * conn ,
bool clear , const char * sql )
{
/* If requested, PGresult must be released before leaving this function. */
PG_TRY ( ) ;
@ -483,6 +485,14 @@ pgfdw_report_error(int elevel, PGresult *res, bool clear, const char *sql)
else
sqlstate = ERRCODE_CONNECTION_FAILURE ;
/*
* If we don ' t get a message from the PGresult , try the PGconn . This
* is needed because for connection - level failures , PQexec may just
* return NULL , not a PGresult at all .
*/
if ( message_primary = = NULL )
message_primary = PQerrorMessage ( conn ) ;
ereport ( elevel ,
( errcode ( sqlstate ) ,
message_primary ? errmsg_internal ( " %s " , message_primary ) :
@ -525,74 +535,37 @@ pgfdw_xact_callback(XactEvent event, void *arg)
{
PGresult * res ;
/* We only care about connections with open remote transactions */
if ( entry - > conn = = NULL | | entry - > xact_depth = = 0 )
/* Ignore cache entry if no open connection right now */
if ( entry - > conn = = NULL )
continue ;
elog ( DEBUG3 , " closing remote transaction on connection %p " ,
entry - > conn ) ;
switch ( event )
/* If it has an open remote transaction, try to close it */
if ( entry - > xact_depth > 0 )
{
case XACT_EVENT_PRE_COMMIT :
/* Commit all remote transactions during pre-commit */
do_sql_command ( entry - > conn , " COMMIT TRANSACTION " ) ;
/*
* If there were any errors in subtransactions , and we made
* prepared statements , do a DEALLOCATE ALL to make sure we
* get rid of all prepared statements . This is annoying and
* not terribly bulletproof , but it ' s probably not worth
* trying harder .
*
* DEALLOCATE ALL only exists in 8.3 and later , so this
* constrains how old a server postgres_fdw can communicate
* with . We intentionally ignore errors in the DEALLOCATE , so
* that we can hobble along to some extent with older servers
* ( leaking prepared statements as we go ; but we don ' t really
* support update operations pre - 8.3 anyway ) .
*/
if ( entry - > have_prep_stmt & & entry - > have_error )
{
res = PQexec ( entry - > conn , " DEALLOCATE ALL " ) ;
PQclear ( res ) ;
}
entry - > have_prep_stmt = false ;
entry - > have_error = false ;
break ;
case XACT_EVENT_PRE_PREPARE :
/*
* We disallow remote transactions that modified anything ,
* since it ' s not really reasonable to hold them open until
* the prepared transaction is committed . For the moment ,
* throw error unconditionally ; later we might allow read - only
* cases . Note that the error will cause us to come right
* back here with event = = XACT_EVENT_ABORT , so we ' ll clean up
* the connection state at that point .
*/
ereport ( ERROR ,
( errcode ( ERRCODE_FEATURE_NOT_SUPPORTED ) ,
errmsg ( " cannot prepare a transaction that modified remote tables " ) ) ) ;
break ;
case XACT_EVENT_COMMIT :
case XACT_EVENT_PREPARE :
/* Should not get here -- pre-commit should have handled it */
elog ( ERROR , " missed cleaning up connection during pre-commit " ) ;
break ;
case XACT_EVENT_ABORT :
/* Assume we might have lost track of prepared statements */
entry - > have_error = true ;
/* If we're aborting, abort all remote transactions too */
res = PQexec ( entry - > conn , " ABORT TRANSACTION " ) ;
/* Note: can't throw ERROR, it would be infinite loop */
if ( PQresultStatus ( res ) ! = PGRES_COMMAND_OK )
pgfdw_report_error ( WARNING , res , true ,
" ABORT TRANSACTION " ) ;
else
{
PQclear ( res ) ;
/* As above, make sure we've cleared any prepared stmts */
elog ( DEBUG3 , " closing remote transaction on connection %p " ,
entry - > conn ) ;
switch ( event )
{
case XACT_EVENT_PRE_COMMIT :
/* Commit all remote transactions during pre-commit */
do_sql_command ( entry - > conn , " COMMIT TRANSACTION " ) ;
/*
* If there were any errors in subtransactions , and we
* made prepared statements , do a DEALLOCATE ALL to make
* sure we get rid of all prepared statements . This is
* annoying and not terribly bulletproof , but it ' s
* probably not worth trying harder .
*
* DEALLOCATE ALL only exists in 8.3 and later , so this
* constrains how old a server postgres_fdw can
* communicate with . We intentionally ignore errors in
* the DEALLOCATE , so that we can hobble along to some
* extent with older servers ( leaking prepared statements
* as we go ; but we don ' t really support update operations
* pre - 8.3 anyway ) .
*/
if ( entry - > have_prep_stmt & & entry - > have_error )
{
res = PQexec ( entry - > conn , " DEALLOCATE ALL " ) ;
@ -600,8 +573,50 @@ pgfdw_xact_callback(XactEvent event, void *arg)
}
entry - > have_prep_stmt = false ;
entry - > have_error = false ;
}
break ;
break ;
case XACT_EVENT_PRE_PREPARE :
/*
* We disallow remote transactions that modified anything ,
* since it ' s not very reasonable to hold them open until
* the prepared transaction is committed . For the moment ,
* throw error unconditionally ; later we might allow
* read - only cases . Note that the error will cause us to
* come right back here with event = = XACT_EVENT_ABORT , so
* we ' ll clean up the connection state at that point .
*/
ereport ( ERROR ,
( errcode ( ERRCODE_FEATURE_NOT_SUPPORTED ) ,
errmsg ( " cannot prepare a transaction that modified remote tables " ) ) ) ;
break ;
case XACT_EVENT_COMMIT :
case XACT_EVENT_PREPARE :
/* Pre-commit should have closed the open transaction */
elog ( ERROR , " missed cleaning up connection during pre-commit " ) ;
break ;
case XACT_EVENT_ABORT :
/* Assume we might have lost track of prepared statements */
entry - > have_error = true ;
/* If we're aborting, abort all remote transactions too */
res = PQexec ( entry - > conn , " ABORT TRANSACTION " ) ;
/* Note: can't throw ERROR, it would be infinite loop */
if ( PQresultStatus ( res ) ! = PGRES_COMMAND_OK )
pgfdw_report_error ( WARNING , res , entry - > conn , true ,
" ABORT TRANSACTION " ) ;
else
{
PQclear ( res ) ;
/* As above, make sure to clear any prepared stmts */
if ( entry - > have_prep_stmt & & entry - > have_error )
{
res = PQexec ( entry - > conn , " DEALLOCATE ALL " ) ;
PQclear ( res ) ;
}
entry - > have_prep_stmt = false ;
entry - > have_error = false ;
}
break ;
}
}
/* Reset state to show we're out of a transaction */
@ -689,7 +704,7 @@ pgfdw_subxact_callback(SubXactEvent event, SubTransactionId mySubid,
curlevel , curlevel ) ;
res = PQexec ( entry - > conn , sql ) ;
if ( PQresultStatus ( res ) ! = PGRES_COMMAND_OK )
pgfdw_report_error ( WARNING , res , true , sql ) ;
pgfdw_report_error ( WARNING , res , entry - > conn , true , sql ) ;
else
PQclear ( res ) ;
}
Tom Lane
12 years ago