Abort transaction if the initiator disconnects.

kvap · kvap · commit 74ff316f122d · 2015-09-20T18:20:28.000+03:00
diff --git a/contrib/pg_xtm/dtmd/include/transaction.h b/contrib/pg_xtm/dtmd/include/transaction.h
@@ -13,6 +13,7 @@ typedef struct Transaction {
 	// true if the transaction was started on the node
 	bool active;
 
+	int client_id;
 	int node;
 	int vote;
 
@@ -25,7 +26,7 @@ typedef struct Transaction {
 
 #define CHAR_TO_INDEX(C) ((C) - 'a')
 typedef struct GlobalTransaction {
-    int n_snapshots;
+	int n_snapshots;
 	Transaction participants[MAX_NODES];
 	void *listeners[CHAR_TO_INDEX('z')]; // we are going to use 'a' to 'z' for indexing
 } GlobalTransaction;
diff --git a/contrib/pg_xtm/dtmd/src/main.c b/contrib/pg_xtm/dtmd/src/main.c
@@ -26,7 +26,6 @@ typedef struct client_data_t {
 } client_data_t;
 
 clog_t clg;
-static bool queue_for_transaction_finish(void *stream, void *clientdata, int node, xid_t xid, char cmd);
 static client_data_t *create_client_data(int id);
 static void free_client_data(client_data_t *cd);
 static void onconnect(void *stream, void **clientdata);
@@ -39,6 +38,7 @@ static void gen_snapshot(Snapshot *s, int node);
 static void gen_snapshots(GlobalTransaction *gt);
 static char *onsnapshot(void *stream, void *clientdata, cmd_t *cmd);
 static bool queue_for_transaction_finish(void *stream, void *clientdata, int node, xid_t xid, char cmd);
+static void notify_listeners(GlobalTransaction *gt, int status);
 static char *onstatus(void *stream, void *clientdata, cmd_t *cmd);
 static char *onnoise(void *stream, void *clientdata, cmd_t *cmd);
 static char *oncmd(void *stream, void *clientdata, cmd_t *cmd);
@@ -68,7 +68,33 @@ static void onconnect(void *stream, void **clientdata) {
 }
 
 static void ondisconnect(void *stream, void *clientdata) {
-	shout("[%d] disconnected\n", CLIENT_ID(clientdata));
+	int client_id = CLIENT_ID(clientdata);
+	shout("[%d] disconnected\n", client_id);
+
+	int i, n;
+	for (i = transactions_count - 1; i >= 0; i--) {
+		GlobalTransaction *gt = transactions + i;
+
+		for (n = 0; n < MAX_NODES; n++) {
+			Transaction *t = gt->participants + n;
+			if ((t->active) && (t->client_id == client_id)) {
+				if (global_transaction_mark(clg, gt, NEGATIVE)) {
+					notify_listeners(gt, NEGATIVE);
+
+					transactions[i] = transactions[transactions_count - 1];
+					transactions_count--;
+				} else {
+					shout(
+						"[%d] DISCONNECT: global transaction failed"
+						" to abort O_o\n",
+						client_id
+					);
+				}
+				break;
+			}
+		}
+	}
+
 	free_client_data(clientdata);
 }
 
@@ -149,6 +175,7 @@ static char *onbegin(void *stream, void *clientdata, cmd_t *cmd) {
 			);
 			return strdup("-");
 		}
+		t->client_id = CLIENT_ID(clientdata);
 		t->active = true;
 		t->node = node;
 		t->vote = DOUBT;
@@ -172,6 +199,32 @@ static char *onbegin(void *stream, void *clientdata, cmd_t *cmd) {
 	return strdup("+");
 }
 
+static void notify_listeners(GlobalTransaction *gt, int status) {
+	void *listener;
+	switch (status) {
+		case NEGATIVE:
+			while ((listener = global_transaction_pop_listener(gt, 's'))) {
+				// notify 'status' listeners about the aborted status
+				write_to_stream(listener, strdup("+a"));
+			}
+			while ((listener = global_transaction_pop_listener(gt, 'c'))) {
+				// notify 'commit' listeners about the failure
+				write_to_stream(listener, strdup("-"));
+			}
+			break;
+		case POSITIVE:
+			while ((listener = global_transaction_pop_listener(gt, 's'))) {
+				// notify 'status' listeners about the committed status
+				write_to_stream(listener, strdup("+c"));
+			}
+			while ((listener = global_transaction_pop_listener(gt, 'c'))) {
+				// notify 'commit' listeners about the success
+				write_to_stream(listener, strdup("+"));
+			}
+			break;
+	}
+}
+
 static char *onvote(void *stream, void *clientdata, cmd_t *cmd, int vote) {
 	assert((vote == POSITIVE) || (vote == NEGATIVE));
 
@@ -218,18 +271,11 @@ static char *onvote(void *stream, void *clientdata, cmd_t *cmd, int vote) {
 	}
 	transactions[i].participants[node].vote = vote;
 
-	switch (global_transaction_status(transactions + i)) {
+	GlobalTransaction *gt = transactions + i;
+	switch (global_transaction_status(gt)) {
 		case NEGATIVE:
-			if (global_transaction_mark(clg, transactions + i, NEGATIVE)) {
-				void *listener;
-				while ((listener = global_transaction_pop_listener(transactions + i, 's'))) {
-					// notify 'status' listeners about the aborted status
-					write_to_stream(listener, strdup("+a"));
-				}
-				while ((listener = global_transaction_pop_listener(transactions + i, 'c'))) {
-					// notify 'commit' listeners about the failure
-					write_to_stream(listener, strdup("-"));
-				}
+			if (global_transaction_mark(clg, gt, NEGATIVE)) {
+				notify_listeners(gt, NEGATIVE);
 
 				transactions[i] = transactions[transactions_count - 1];
 				transactions_count--;
@@ -258,20 +304,7 @@ static char *onvote(void *stream, void *clientdata, cmd_t *cmd, int vote) {
 			}
 		case POSITIVE:
 			if (global_transaction_mark(clg, transactions + i, POSITIVE)) {
-				//shout(
-				//	"[%d] VOTE: global transaction committed\n",
-				//	CLIENT_ID(clientdata)
-				//);
-
-				void *listener;
-				while ((listener = global_transaction_pop_listener(transactions + i, 's'))) {
-					// notify 'status' listeners about the committed status
-					write_to_stream(listener, strdup("+c"));
-				}
-				while ((listener = global_transaction_pop_listener(transactions + i, 'c'))) {
-					// notify 'commit' listeners about the success
-					write_to_stream(listener, strdup("+"));
-				}
+				notify_listeners(gt, POSITIVE);
 
 				transactions[i] = transactions[transactions_count - 1];
 				transactions_count--;
diff --git a/contrib/pg_xtm/dtmd/src/transaction.c b/contrib/pg_xtm/dtmd/src/transaction.c
@@ -58,7 +58,7 @@ bool global_transaction_mark(clog_t clg, GlobalTransaction *gt, int status) {
 
 void global_transaction_clear(GlobalTransaction *gt) {
 	int i;
-    gt->n_snapshots = 0;
+	gt->n_snapshots = 0;
 	for (i = 0; i < MAX_NODES; i++) {
 		gt->participants[i].active = false;
 	}

Original file line number	Diff line number	Diff line change
`@@ -58,7 +58,7 @@ bool global_transaction_mark(clog_t clg, GlobalTransaction *gt, int status) {`
`58`	`58`
`59`	`59`	`void global_transaction_clear(GlobalTransaction *gt) {`
`60`	`60`	`int i;`
`61`		`- gt->n_snapshots = 0;`
	`61`	`+ gt->n_snapshots = 0;`
`62`	`62`	`for (i = 0; i < MAX_NODES; i++) {`
`63`	`63`	`gt->participants[i].active = false;`
`64`	`64`	`}`