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Add Bron–Kerbosch algorithm to find maximum clique in graph
1 parent 0f74000 commit 3492d3d

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9 files changed

+166
-89
lines changed

9 files changed

+166
-89
lines changed

‎contrib/mmts/Makefile

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
MODULE_big = multimaster
2-
OBJS = multimaster.o arbiter.o bytebuf.o bgwpool.o pglogical_output.o pglogical_proto.o pglogical_receiver.o pglogical_apply.o pglogical_hooks.o pglogical_config.o
2+
OBJS = multimaster.o arbiter.o bytebuf.o bgwpool.o pglogical_output.o pglogical_proto.o pglogical_receiver.o pglogical_apply.o pglogical_hooks.o pglogical_config.o ddd.o bkb.o
33

44
EXTENSION = multimaster
55
DATA = multimaster--1.0.sql

‎contrib/mmts/arbiter.c

Lines changed: 7 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -81,7 +81,7 @@ typedef struct
8181
MtmMessageCode code; /* Message code: MSG_READY, MSG_PREPARE, MSG_COMMIT, MSG_ABORT */
8282
int node; /* Sender node ID */
8383
TransactionId dxid; /* Transaction ID at destination node */
84-
TransactionId sxid; /* Transaction IO at sender node */
84+
TransactionId sxid; /* Transaction ID at sender node */
8585
csn_t csn; /* local CSN in case of sending data from replica to master, global CSN master->replica */
8686
nodemask_t disabledNodeMask; /* bitmask of disabled nodes at the sender of message */
8787
} MtmArbiterMessage;
@@ -353,9 +353,11 @@ static void MtmOpenConnections()
353353

354354
static bool MtmSendToNode(int node, void const* buf, int size)
355355
{
356-
while (!MtmWriteSocket(sockets[node], buf, size)) {
356+
while (sockets[node] < 0 || !MtmWriteSocket(sockets[node], buf, size)) {
357357
elog(WARNING, "Arbiter failed to write socket: %d", errno);
358-
close(sockets[node]);
358+
if (sockets[node] >= 0) {
359+
close(sockets[node]);
360+
}
359361
sockets[node] = MtmConnectSocket(hosts[node], MtmArbiterPort + node + 1, MtmReconnectAttempts);
360362
if (sockets[node] < 0) {
361363
MtmOnLostConnection(node+1);
@@ -400,6 +402,8 @@ static void MtmAcceptOneConnection()
400402
close(fd);
401403
} else {
402404
elog(NOTICE, "Arbiter established connection with node %d", msg.node);
405+
BIT_CLEAR(ds->connectivityMask, msg.node-1);
406+
MtmOnConnectNode(msg.node);
403407
MtmRegisterSocket(fd, msg.node-1);
404408
sockets[msg.node-1] = fd;
405409
}

‎contrib/mmts/bkb.c

Lines changed: 30 additions & 21 deletions
Original file line numberDiff line numberDiff line change
@@ -1,18 +1,22 @@
1+
#include "postgres.h"
2+
#include "bkb.h"
3+
14
/*
2-
* Bron–Kerbosch algorithm to find maximum clque in graph
5+
* Bron–Kerbosch algorithm to find maximum clique in graph
36
*/
47

58
typedef struct {
69
int size;
710
int nodes[MAX_NODES];
8-
} List;
11+
} NodeList;
912

10-
static void list_append(List* list, int n)
13+
static void list_append(NodeList* list, int n)
1114
{
12-
nodes[list->size++] = n;
15+
Assert(list->size < MAX_NODES);
16+
list->nodes[list->size++] = n;
1317
}
1418

15-
static void list_copy(List* dst, List* src)
19+
static void list_copy(NodeList* dst, NodeList const* src)
1620
{
1721
int i;
1822
int n = src->size;
@@ -23,13 +27,15 @@ static void list_copy(List* dst, List* src)
2327
}
2428

2529

26-
static void findMaximumIndependentSet(List* cur, List* result, nodemask_t* graph, int* oldSet, int ne, int ce)
30+
static void findMaximumIndependentSet(NodeList* cur, NodeList* result, nodemask_t* graph, int* oldSet, int ne, int ce)
2731
{
2832
int nod = 0;
2933
int minnod = ce;
3034
int fixp = -1;
3135
int s = -1;
32-
int i, j;
36+
int i, j, k;
37+
int newce, newne;
38+
int sel;
3339
int newSet[MAX_NODES];
3440

3541
for (i = 0; i < ce && minnod != 0; i++) {
@@ -39,8 +45,9 @@ static void findMaximumIndependentSet(List* cur, List* result, nodemask_t* graph
3945

4046
for (j = ne; j < ce; j++) {
4147
if (!BIT_CHECK(graph[p], oldSet[j])) {
42-
if (++cnt == minnod)
48+
if (++cnt == minnod) {
4349
break;
50+
}
4451
pos = j;
4552
}
4653
}
@@ -57,19 +64,19 @@ static void findMaximumIndependentSet(List* cur, List* result, nodemask_t* graph
5764
}
5865

5966

60-
for (int k = minnod + nod; k >= 1; k--) {
61-
int sel = oldSet[s];
67+
for (k = minnod + nod; k >= 1; k--) {
68+
sel = oldSet[s];
6269
oldSet[s] = oldSet[ne];
6370
oldSet[ne] = sel;
6471

65-
int newne = 0;
66-
for (int i = 0; i < ne; i++) {
72+
newne = 0;
73+
for (i = 0; i < ne; i++) {
6774
if (BIT_CHECK(graph[sel], oldSet[i])) {
6875
newSet[newne++] = oldSet[i];
6976
}
7077
}
71-
int newce = newne;
72-
for (int i = ne + 1; i < ce; i++) {
78+
newce = newne;
79+
for (i = ne + 1; i < ce; i++) {
7380
if (BIT_CHECK(graph[sel], oldSet[i])) {
7481
newSet[newce++] = oldSet[i];
7582
}
@@ -84,28 +91,30 @@ static void findMaximumIndependentSet(List* cur, List* result, nodemask_t* graph
8491
findMaximumIndependentSet(cur, result, graph, newSet, newne, newce);
8592
}
8693
}
87-
cur.size -= 1;
94+
cur->size -= 1;
8895
if (k > 1) {
8996
for (s = ++ne; BIT_CHECK(graph[fixp], oldSet[s]); s++);
9097
}
9198
}
9299
}
93100

94-
nodemask_t MtmFindMaxClique(nodemask_t* graphs, in n_nodes);
101+
nodemask_t MtmFindMaxClique(nodemask_t* graph, int n_nodes)
95102
{
96-
List tmp;
97-
List result;
98-
nodemask_t mask = 0;
103+
NodeList tmp;
104+
NodeList result;
105+
nodemask_t mask;
99106
int all[MAX_NODES];
100107
int i;
108+
101109
tmp.size = 0;
102110
result.size = 0;
103111
for (i = 0; i < n_nodes; i++) {
104-
all[i]= i;
112+
all[i] = i;
105113
}
106114
findMaximumIndependentSet(&tmp, &result, graph, all, 0, n_nodes);
115+
mask = 0;
107116
for (i = 0; i < result.size; i++) {
108117
mask |= (nodemask_t)1 << result.nodes[i];
109118
}
110-
return ~mask;
119+
return mask;
111120
}

‎contrib/mmts/bkb.h

Lines changed: 16 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,16 @@
1+
/*
2+
* Bron–Kerbosch algorithm to find maximum clique in graph
3+
*/
4+
#ifndef __BKB_H__
5+
#define __BKB_H__
6+
7+
#define MAX_NODES 64
8+
9+
typedef uint64_t nodemask_t;
10+
#define BIT_CHECK(mask, bit) (((mask) & ((nodemask_t)1 << (bit))) != 0)
11+
#define BIT_CLEAR(mask, bit) (mask &= ~((nodemask_t)1 << (bit)))
12+
#define BIT_SET(mask, bit) (mask |= ((nodemask_t)1 << (bit)))
13+
14+
extern nodemask_t MtmFindMaxClique(nodemask_t* matrix, int n_modes);
15+
16+
#endif

‎contrib/mmts/ddd.c

Lines changed: 19 additions & 19 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,8 @@
1-
#include <stddef.h>
2-
#include <stdlib.h>
3-
#include <string.h>
1+
#include "postgres.h"
2+
#include "access/clog.h"
3+
#include "storage/lwlock.h"
4+
#include "utils/hsearch.h"
5+
46
#include "ddd.h"
57

68

@@ -11,10 +13,10 @@ void MtmGraphInit(MtmGraph* graph)
1113

1214
static inline MtmVertex* findVertex(MtmGraph* graph, GlobalTransactionId* gtid)
1315
{
14-
xid_t h = gtid->xid % MAX_TRANSACTIONS;
16+
uint32 h = gtid->xid % MAX_TRANSACTIONS;
1517
MtmVertex* v;
16-
for (v = graph->hashtable[h]; v != NULL; v = v->next) {
17-
if (v->gtid == *gtid) {
18+
for (v = graph->hashtable[h]; v != NULL; v = v->collision) {
19+
if (EQUAL_GTID(v->gtid, *gtid)) {
1820
return v;
1921
}
2022
}
@@ -29,30 +31,28 @@ static inline MtmVertex* findVertex(MtmGraph* graph, GlobalTransactionId* gtid)
2931
void MtmGraphAdd(MtmGraph* graph, GlobalTransactionId* gtid, int size)
3032
{
3133
GlobalTransactionId* last = gtid + size;
32-
MtmEdge *e, *next, *edges = NULL;
3334
while (gtid != last) {
34-
Vertex* src = findVertex(graph, gtid++);
35+
MtmVertex* src = findVertex(graph, gtid++);
3536
while (gtid->node != 0) {
36-
Vertex* dst = findVertex(graph, gtid++);
37-
e = (MtmEdge*)palloc(sizeof(MtmEdge));
38-
dst->nIncomingEdges += 1;
37+
MtmVertex* dst = findVertex(graph, gtid++);
38+
MtmEdge* e = (MtmEdge*)palloc(sizeof(MtmEdge));
3939
e->dst = dst;
4040
e->src = src;
41-
e->next = v->outgoingEdges;
42-
v->outgoingEdges = e;
41+
e->next = src->outgoingEdges;
42+
src->outgoingEdges = e;
4343
}
4444
gtid += 1;
4545
}
4646
}
4747

4848
static bool recursiveTraverseGraph(MtmVertex* root, MtmVertex* v)
4949
{
50-
Edge* e;
51-
v->node = VISITED_NODE_MARK;
50+
MtmEdge* e;
51+
v->gtid.node = VISITED_NODE_MARK;
5252
for (e = v->outgoingEdges; e != NULL; e = e->next) {
5353
if (e->dst == root) {
5454
return true;
55-
} else if (e->dst->node != VISITED_NODE_MAR && recursiveTraverseGraph(root, e->dst)) { /* loop */
55+
} else if (e->dst->gtid.node != VISITED_NODE_MARK && recursiveTraverseGraph(root, e->dst)) { /* loop */
5656
return true;
5757
}
5858
}
@@ -61,9 +61,9 @@ static bool recursiveTraverseGraph(MtmVertex* root, MtmVertex* v)
6161

6262
bool MtmGraphFindLoop(MtmGraph* graph, GlobalTransactionId* root)
6363
{
64-
Vertex* v;
65-
for (v = graph->hashtable[root->xid % MAX_TRANSACTIONS]; v != NULL; v = v->next) {
66-
if (v->gtid == *root) {
64+
MtmVertex* v;
65+
for (v = graph->hashtable[root->xid % MAX_TRANSACTIONS]; v != NULL; v = v->collision) {
66+
if (EQUAL_GTID(v->gtid, *root)) {
6767
if (recursiveTraverseGraph(v, v)) {
6868
return true;
6969
}

‎contrib/mmts/ddd.h

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,5 @@
11
#ifndef __DDD_H__
2+
#define __DDD_H__
23

34
#include "multimaster.h"
45

@@ -20,8 +21,8 @@ typedef struct MtmVertex
2021

2122
typedef struct MtmGraph
2223
{
23-
MtmVertex* hashtable[MTM_MAX_TRANSACTIONS];
24-
} Graph;
24+
MtmVertex* hashtable[MAX_TRANSACTIONS];
25+
} MtmGraph;
2526

2627
extern void MtmGraphInit(MtmGraph* graph);
2728
extern void MtmGraphAdd(MtmGraph* graph, GlobalTransactionId* subgraph, int size);

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