From 836d2d097d7af887aa360a42f346054aaedbff44 Mon Sep 17 00:00:00 2001
From: Sears Russell <sears@cs.berkeley.edu>
Date: Thu, 5 Oct 2006 00:50:21 +0000
Subject: [PATCH] Fixed initialization bugs on pendingCommits and syncLogCount.
  Group commit used to hang with 100% CPU if a signal interrputed it.  Now it
 ignores the signal.  (Don't know why it's receiving a singal, so it warns
 when this happens...)

---
 src/lladd/logger/logger2.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/src/lladd/logger/logger2.c b/src/lladd/logger/logger2.c
index 6042fca..a5a6708 100644
--- a/src/lladd/logger/logger2.c
+++ b/src/lladd/logger/logger2.c
@@ -61,6 +61,10 @@ terms specified in this license.
 
 int loggerType = LOG_TO_FILE;
 
+extern int numActiveXactions;
+static int pendingCommits;
+static int syncLogCount;
+
 long LoggerSizeOfInternalLogEntry(const LogEntry * e) {
   if(loggerType == LOG_TO_FILE) { 
     return sizeofInternalLogEntry_LogWriter(e);
@@ -87,6 +91,8 @@ int LogInit(int logType) {
 
   loggerType = logType;
 
+  pendingCommits = 0;
+  syncLogCount = 0;
   if(LOG_TO_FILE == logType) { 
     openLogWriter();
   } else if(LOG_TO_MEMORY == logType) { 
@@ -209,21 +215,17 @@ static lsn_t LogTransCommon(TransactionLog * l, int type) {
 
 }
 
-extern int numActiveXactions;
 /**
-   @todo This belongs in logWriter.c and needs a new name.
+   @todo This should be usable by all calls that sync the log; not just commit.
 */
 static lsn_t groupCommit(TransactionLog * l) {
   static pthread_mutex_t check_commit = PTHREAD_MUTEX_INITIALIZER;
   static pthread_cond_t tooFewXacts = PTHREAD_COND_INITIALIZER;
-  static int pendingCommits = 0;
-  static int syncLogCount;
 
   lsn_t ret = LogTransCommon(l, XCOMMIT);
 
   struct timeval now;
   struct timespec timeout;
-  //  int retcode;
   
   pthread_mutex_lock(&check_commit);
   if(LogFlushedLSN() >= ret) {
@@ -241,24 +243,24 @@ static lsn_t groupCommit(TransactionLog * l) {
   }
 
   pendingCommits++;
-  //  if(pendingCommits <= (numActiveXactions / 2)) {
   if((numActiveXactions > 1 && pendingCommits < numActiveXactions) ||
      (numActiveXactions > 20 && pendingCommits < (int)((double)numActiveXactions * 0.95))) {
-    while(ETIMEDOUT != (pthread_cond_timedwait(&tooFewXacts, &check_commit, &timeout))) {
+    int retcode;
+    while(ETIMEDOUT != (retcode = pthread_cond_timedwait(&tooFewXacts, &check_commit, &timeout))) { 
+      if(retcode != 0) { 
+	printf("Warning: %s:%d: pthread_cond_timedwait was interrupted by a signal in groupCommit().  Acting as though it timed out.\n", __FILE__, __LINE__);
+	break;
+      }
       if(LogFlushedLSN() >= ret) {
 	pendingCommits--;
 	pthread_mutex_unlock(&check_commit);
 	return ret;
       }
     }
-    //    printf("Timed out");
-  } else {
-    //     printf("Didn't wait %d < %d\n", (numActiveXactions / 2), pendingCommits);
   } 
   if(LogFlushedLSN() < ret) {
     syncLog_LogWriter();
     syncLogCount++;
-    //    printf(" %d ", syncLogCount);
     pthread_cond_broadcast(&tooFewXacts);
   }
   assert(LogFlushedLSN() >= ret);
@@ -312,7 +314,6 @@ LogEntry * LogUpdate(TransactionLog * l, Page * p, recordid rid, int operation,
   
   e = allocUpdateLogEntry(l->prevLSN, l->xid, operation, rid, args, argSize, preImage);
   
-  //  writeLogEntry(e); 
   LogWrite(e);
   DEBUG("Log Common %d, LSN: %ld type: %ld (prevLSN %ld) (argSize %ld)\n", e->xid, 
 	 (long int)e->LSN, (long int)e->type, (long int)e->prevLSN, (long int) argSize);