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kelvichkelvich
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port fdw patches
1 parent 2aa6c03 commit 7607a30

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4 files changed

+284
-41
lines changed

4 files changed

+284
-41
lines changed

‎contrib/postgres_fdw/connection.c

Lines changed: 230 additions & 31 deletions
Original file line numberDiff line numberDiff line change
@@ -17,6 +17,8 @@
1717
#include "access/htup_details.h"
1818
#include "catalog/pg_user_mapping.h"
1919
#include "access/xact.h"
20+
#include "access/xtm.h"
21+
#include "access/transam.h"
2022
#include "mb/pg_wchar.h"
2123
#include "miscadmin.h"
2224
#include "pgstat.h"
@@ -72,12 +74,18 @@ static unsigned int prep_stmt_number = 0;
7274
/* tracks whether any work is needed in callback functions */
7375
static bool xact_got_connection = false;
7476

77+
typedef long long csn_t;
78+
static csn_t currentGlobalTransactionId = 0;
79+
static int currentLocalTransactionId = 0;
80+
static PGconn* currentConnection = NULL;
81+
7582
/* prototypes of private functions */
7683
static PGconn *connect_pg_server(ForeignServer *server, UserMapping *user);
7784
static void disconnect_pg_server(ConnCacheEntry *entry);
7885
static void check_conn_params(const char **keywords, const char **values);
7986
static void configure_remote_session(PGconn *conn);
8087
static void do_sql_command(PGconn *conn, const char *sql);
88+
static void do_sql_send_command(PGconn *conn, const char *sql);
8189
static void begin_remote_xact(ConnCacheEntry *entry);
8290
static void pgfdw_xact_callback(XactEvent event, void *arg);
8391
static void pgfdw_subxact_callback(SubXactEvent event,
@@ -403,6 +411,19 @@ do_sql_command(PGconn *conn, const char *sql)
403411
PQclear(res);
404412
}
405413

414+
static void
415+
do_sql_send_command(PGconn *conn, const char *sql)
416+
{
417+
if (PQsendQuery(conn, sql) != PGRES_COMMAND_OK)
418+
{
419+
PGresult *res = PQgetResult(conn);
420+
421+
elog(WARNING, "Failed to send command %s", sql);
422+
pgfdw_report_error(ERROR, res, conn, true, sql);
423+
PQclear(res);
424+
}
425+
}
426+
406427
/*
407428
* Start remote transaction or subtransaction, if needed.
408429
*
@@ -417,15 +438,26 @@ static void
417438
begin_remote_xact(ConnCacheEntry *entry)
418439
{
419440
int curlevel = GetCurrentTransactionNestLevel();
441+
PGresult *res;
442+
420443

421444
/* Start main transaction if we haven't yet */
422445
if (entry->xact_depth <= 0)
423446
{
447+
TransactionId gxid = GetTransactionManager()->GetGlobalTransactionId();
424448
const char *sql;
425449

426450
elog(DEBUG3, "starting remote transaction on connection %p",
427451
entry->conn);
428452

453+
if (TransactionIdIsValid(gxid))
454+
{
455+
char stmt[64];
456+
snprintf(stmt, sizeof(stmt), "select public.dtm_join_transaction(%d)", gxid);
457+
res = PQexec(entry->conn, stmt);
458+
PQclear(res);
459+
}
460+
429461
if (IsolationIsSerializable())
430462
sql = "START TRANSACTION ISOLATION LEVEL SERIALIZABLE";
431463
else
@@ -434,6 +466,41 @@ begin_remote_xact(ConnCacheEntry *entry)
434466
do_sql_command(entry->conn, sql);
435467
entry->xact_depth = 1;
436468
entry->changing_xact_state = false;
469+
470+
if (UseTsDtmTransactions)
471+
{
472+
if (currentConnection == NULL)
473+
{
474+
currentConnection = entry->conn;
475+
}
476+
else if (entry->conn != currentConnection)
477+
{
478+
if (!currentGlobalTransactionId)
479+
{
480+
char *resp;
481+
res = PQexec(currentConnection, psprintf("SELECT public.dtm_extend('%d.%d')",
482+
MyProcPid, ++currentLocalTransactionId));
483+
484+
if (PQresultStatus(res) != PGRES_TUPLES_OK)
485+
{
486+
pgfdw_report_error(ERROR, res, currentConnection, true, sql);
487+
}
488+
resp = PQgetvalue(res, 0, 0);
489+
if (resp == NULL || (*resp) == '\0' || sscanf(resp, "%lld", &currentGlobalTransactionId) != 1)
490+
{
491+
pgfdw_report_error(ERROR, res, currentConnection, true, sql);
492+
}
493+
PQclear(res);
494+
}
495+
res = PQexec(entry->conn, psprintf("SELECT public.dtm_access(%llu, '%d.%d')", currentGlobalTransactionId, MyProcPid, currentLocalTransactionId));
496+
497+
if (PQresultStatus(res) != PGRES_TUPLES_OK)
498+
{
499+
pgfdw_report_error(ERROR, res, entry->conn, true, sql);
500+
}
501+
PQclear(res);
502+
}
503+
}
437504
}
438505

439506
/*
@@ -643,6 +710,78 @@ pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
643710
PQclear(res);
644711
}
645712

713+
typedef bool (*DtmCommandResultHandler) (PGresult *result, void *arg);
714+
715+
static bool
716+
RunDtmStatement(char const * sql, unsigned expectedStatus, DtmCommandResultHandler handler, void *arg)
717+
{
718+
HASH_SEQ_STATUS scan;
719+
ConnCacheEntry *entry;
720+
bool allOk = true;
721+
722+
hash_seq_init(&scan, ConnectionHash);
723+
while ((entry = (ConnCacheEntry *) hash_seq_search(&scan)))
724+
{
725+
if (entry->xact_depth > 0)
726+
{
727+
do_sql_send_command(entry->conn, sql);
728+
}
729+
}
730+
731+
hash_seq_init(&scan, ConnectionHash);
732+
while ((entry = (ConnCacheEntry *) hash_seq_search(&scan)))
733+
{
734+
if (entry->xact_depth > 0)
735+
{
736+
PGresult *result = PQgetResult(entry->conn);
737+
738+
if (PQresultStatus(result) != expectedStatus || (handler && !handler(result, arg)))
739+
{
740+
elog(WARNING, "Failed command %s: status=%d, expected status=%d", sql, PQresultStatus(result), expectedStatus);
741+
pgfdw_report_error(ERROR, result, entry->conn, true, sql);
742+
allOk = false;
743+
}
744+
PQclear(result);
745+
PQgetResult(entry->conn); /* consume NULL result */
746+
}
747+
}
748+
return allOk;
749+
}
750+
751+
static bool
752+
RunDtmCommand(char const * sql)
753+
{
754+
return RunDtmStatement(sql, PGRES_COMMAND_OK, NULL, NULL);
755+
}
756+
757+
static bool
758+
RunDtmFunction(char const * sql)
759+
{
760+
return RunDtmStatement(sql, PGRES_TUPLES_OK, NULL, NULL);
761+
}
762+
763+
764+
static bool
765+
DtmMaxCSN(PGresult *result, void *arg)
766+
{
767+
char *resp = PQgetvalue(result, 0, 0);
768+
csn_t *maxCSN = (csn_t *) arg;
769+
csn_t csn = 0;
770+
771+
if (resp == NULL || (*resp) == '\0' || sscanf(resp, "%lld", &csn) != 1)
772+
{
773+
return false;
774+
}
775+
else
776+
{
777+
if (*maxCSN < csn)
778+
{
779+
*maxCSN = csn;
780+
}
781+
return true;
782+
}
783+
}
784+
646785
/*
647786
* pgfdw_xact_callback --- cleanup at main-transaction end.
648787
*/
@@ -652,10 +791,55 @@ pgfdw_xact_callback(XactEvent event, void *arg)
652791
HASH_SEQ_STATUS scan;
653792
ConnCacheEntry *entry;
654793

794+
/* Do nothing for this events */
795+
switch (event)
796+
{
797+
case XACT_EVENT_START:
798+
case XACT_EVENT_COMMIT_PREPARED:
799+
case XACT_EVENT_ABORT_PREPARED:
800+
return;
801+
default:
802+
break;
803+
}
804+
655805
/* Quick exit if no connections were touched in this transaction. */
656806
if (!xact_got_connection)
657807
return;
658808

809+
if (currentGlobalTransactionId != 0)
810+
{
811+
switch (event)
812+
{
813+
case XACT_EVENT_PARALLEL_PRE_COMMIT:
814+
case XACT_EVENT_PRE_COMMIT:
815+
{
816+
csn_t maxCSN = 0;
817+
818+
if (!RunDtmCommand(psprintf("PREPARE TRANSACTION '%d.%d'",
819+
MyProcPid, currentLocalTransactionId)) ||
820+
!RunDtmFunction(psprintf("SELECT public.dtm_begin_prepare('%d.%d')",
821+
MyProcPid, currentLocalTransactionId)) ||
822+
!RunDtmStatement(psprintf("SELECT public.dtm_prepare('%d.%d',0)",
823+
MyProcPid, currentLocalTransactionId), PGRES_TUPLES_OK, DtmMaxCSN, &maxCSN) ||
824+
!RunDtmFunction(psprintf("SELECT public.dtm_end_prepare('%d.%d',%lld)",
825+
MyProcPid, currentLocalTransactionId, maxCSN)) ||
826+
!RunDtmCommand(psprintf("COMMIT PREPARED '%d.%d'",
827+
MyProcPid, currentLocalTransactionId)))
828+
{
829+
RunDtmCommand(psprintf("ROLLBACK PREPARED '%d.%d'",
830+
MyProcPid, currentLocalTransactionId));
831+
ereport(ERROR,
832+
(errcode(ERRCODE_TRANSACTION_ROLLBACK),
833+
errmsg("transaction was aborted at one of the shards")));
834+
break;
835+
}
836+
return;
837+
}
838+
default:
839+
break;
840+
}
841+
}
842+
659843
/*
660844
* Scan all connection cache entries to find open remote transactions, and
661845
* close them.
@@ -689,10 +873,34 @@ pgfdw_xact_callback(XactEvent event, void *arg)
689873
pgfdw_reject_incomplete_xact_state_change(entry);
690874

691875
/* Commit all remote transactions during pre-commit */
692-
entry->changing_xact_state = true;
693-
do_sql_command(entry->conn, "COMMIT TRANSACTION");
694-
entry->changing_xact_state = false;
876+
do_sql_send_command(entry->conn, "COMMIT TRANSACTION");
877+
continue;
878+
879+
case XACT_EVENT_PRE_PREPARE:
880+
881+
/*
882+
* We disallow remote transactions that modified anything,
883+
* since it's not very reasonable to hold them open until
884+
* the prepared transaction is committed. For the moment,
885+
* throw error unconditionally; later we might allow
886+
* read-only cases. Note that the error will cause us to
887+
* come right back here with event == XACT_EVENT_ABORT, so
888+
* we'll clean up the connection state at that point.
889+
*/
890+
ereport(ERROR,
891+
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
892+
errmsg("cannot prepare a transaction that modified remote tables")));
893+
break;
695894

895+
case XACT_EVENT_PARALLEL_COMMIT:
896+
case XACT_EVENT_COMMIT:
897+
case XACT_EVENT_PREPARE:
898+
if (!currentGlobalTransactionId)
899+
{
900+
entry->changing_xact_state = true;
901+
do_sql_command(entry->conn, "COMMIT TRANSACTION");
902+
entry->changing_xact_state = false;
903+
}
696904
/*
697905
* If there were any errors in subtransactions, and we
698906
* made prepared statements, do a DEALLOCATE ALL to make
@@ -716,27 +924,7 @@ pgfdw_xact_callback(XactEvent event, void *arg)
716924
entry->have_prep_stmt = false;
717925
entry->have_error = false;
718926
break;
719-
case XACT_EVENT_PRE_PREPARE:
720927

721-
/*
722-
* We disallow remote transactions that modified anything,
723-
* since it's not very reasonable to hold them open until
724-
* the prepared transaction is committed. For the moment,
725-
* throw error unconditionally; later we might allow
726-
* read-only cases. Note that the error will cause us to
727-
* come right back here with event == XACT_EVENT_ABORT, so
728-
* we'll clean up the connection state at that point.
729-
*/
730-
ereport(ERROR,
731-
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
732-
errmsg("cannot prepare a transaction that modified remote tables")));
733-
break;
734-
case XACT_EVENT_PARALLEL_COMMIT:
735-
case XACT_EVENT_COMMIT:
736-
case XACT_EVENT_PREPARE:
737-
/* Pre-commit should have closed the open transaction */
738-
elog(ERROR, "missed cleaning up connection during pre-commit");
739-
break;
740928
case XACT_EVENT_PARALLEL_ABORT:
741929
case XACT_EVENT_ABORT:
742930

@@ -800,6 +988,11 @@ pgfdw_xact_callback(XactEvent event, void *arg)
800988
/* Disarm changing_xact_state if it all worked. */
801989
entry->changing_xact_state = abort_cleanup_failure;
802990
break;
991+
992+
case XACT_EVENT_START:
993+
case XACT_EVENT_COMMIT_PREPARED:
994+
case XACT_EVENT_ABORT_PREPARED:
995+
break;
803996
}
804997
}
805998

@@ -818,16 +1011,22 @@ pgfdw_xact_callback(XactEvent event, void *arg)
8181011
disconnect_pg_server(entry);
8191012
}
8201013
}
1014+
if (event != XACT_EVENT_PARALLEL_PRE_COMMIT && event != XACT_EVENT_PRE_COMMIT)
1015+
{
1016+
/*
1017+
* Regardless of the event type, we can now mark ourselves as out of
1018+
* the transaction. (Note: if we are here during PRE_COMMIT or
1019+
* PRE_PREPARE, this saves a useless scan of the hashtable during
1020+
* COMMIT or PREPARE.)
1021+
*/
1022+
xact_got_connection = false;
8211023

822-
/*
823-
* Regardless of the event type, we can now mark ourselves as out of the
824-
* transaction. (Note: if we are here during PRE_COMMIT or PRE_PREPARE,
825-
* this saves a useless scan of the hashtable during COMMIT or PREPARE.)
826-
*/
827-
xact_got_connection = false;
1024+
/* Also reset cursor numbering for next transaction */
1025+
cursor_number = 0;
8281026

829-
/* Also reset cursor numbering for next transaction */
830-
cursor_number = 0;
1027+
currentGlobalTransactionId = 0;
1028+
currentConnection = NULL;
1029+
}
8311030
}
8321031

8331032
/*

‎contrib/postgres_fdw/postgres_fdw--1.0.sql

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -16,3 +16,8 @@ LANGUAGE C STRICT;
1616
CREATE FOREIGN DATA WRAPPER postgres_fdw
1717
HANDLER postgres_fdw_handler
1818
VALIDATOR postgres_fdw_validator;
19+
20+
CREATE FUNCTION postgres_fdw_exec(relid oid, sql cstring)
21+
RETURNS void
22+
AS 'MODULE_PATHNAME'
23+
LANGUAGE C STRICT;

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