Some experimates with multimaster performance

Author: knizhnik

contrib/multimaster/bgwpool.c

@@ -16,6 +16,9 @@ typedef struct
     int id;
 } BgwPoolExecutorCtx;
 
+size_t n_snapshots;
+size_t n_active;
+
 static void BgwPoolMainLoop(Datum arg)
 {
     BgwPoolExecutorCtx* ctx = (BgwPoolExecutorCtx*)arg;
@@ -35,6 +38,7 @@ static void BgwPoolMainLoop(Datum arg)
         size = *(int*)&pool->queue[pool->head];
         Assert(size < pool->size);
         work = palloc(size);
+        pool->active -= 1;
         if (pool->head + size + 4 > pool->size) { 
             memcpy(work, pool->queue, size);
             pool->head = INTALIGN(size);
@@ -68,6 +72,7 @@ void BgwPoolInit(BgwPool* pool, BgwPoolExecutor executor, char const* dbname, si
     pool->head = 0;
     pool->tail = 0;
     pool->size = queueSize;
+    pool->active = 0;
     strcpy(pool->dbname, dbname);
 }
 
@@ -106,6 +111,9 @@ void BgwPoolExecute(BgwPool* pool, void* work, size_t size)
             PGSemaphoreLock(&pool->overflow);
             SpinLockAcquire(&pool->lock);
         } else {
+            pool->active += 1;
+            n_snapshots += 1;
+            n_active += pool->active;
             *(int*)&pool->queue[pool->tail] = size;
             if (pool->size - pool->tail >= size + 4) { 
                 memcpy(&pool->queue[pool->tail+4], work, size);

contrib/multimaster/bgwpool.h

@@ -18,6 +18,7 @@ typedef struct
     size_t head;
     size_t tail;
     size_t size;
+    size_t active;
     bool   producerBlocked;
     char   dbname[MAX_DBNAME_LEN];
     char*  queue;

contrib/multimaster/multimaster.h

@@ -4,8 +4,8 @@
 #include "bytebuf.h"
 
 #define XTM_TRACE(fmt, ...)
-#define XTM_INFO(fmt, ...) fprintf(stderr, fmt, ## __VA_ARGS__)
-//#define XTM_INFO(fmt, ...)
+//#define XTM_INFO(fmt, ...) fprintf(stderr, fmt, ## __VA_ARGS__)
+#define XTM_INFO(fmt, ...)
 
 extern int  MMStartReceivers(char* nodes, int node_id);
 extern void MMBeginTransaction(void);

contrib/multimaster/receiver_raw.c

@@ -269,7 +269,6 @@ receiver_raw_main(Datum main_arg)
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 					   receiver_idle_time * 1L);
 		ResetLatch(&MyProc->procLatch);
-
 		/* Process signals */
 		if (got_sighup)
 		{

contrib/multimaster/tests/dtmbench

@@ -200,11 +200,9 @@ int main (int argc, char* argv[])
                "\t-r N\tnumber of readers (1)\n"
                "\t-w N\tnumber of writers (10)\n"
                "\t-a N\tnumber of accounts (100000)\n"
-               "\t-s N\tperform updates starting from this id (1)\n"
-               "\t-d N\tperform updates in this diapason (100000)\n"
                "\t-n N\tnumber of iterations (1000)\n"
                "\t-c STR\tdatabase connection string\n"
-               "\t-i\tinitialize datanase\n");
+               "\t-i\tinitialize database\n");
         return 1;
     }