Robust/src/Runtime/DSTM/interface/trans.c

   1 #include "dstm.h"
   2 #include "ip.h"
   3 #include "clookup.h"
   4 #include "mlookup.h"
   5 #include "llookup.h"
   6 #include "plookup.h"
   7 #include "queue.h"
   8 #include <pthread.h>
   9 #include <sys/types.h>
  10 #include <sys/socket.h>
  11 #include <netdb.h>
  12 #include <netinet/in.h>
  13 #include <sys/types.h>
  14 #include <unistd.h>
  15 #include <time.h>
  16 #include <string.h>
  17 #include <pthread.h>
  18
  19 #define LISTEN_PORT 2156
  20 #define RECEIVE_BUFFER_SIZE 2048
  21 #define NUM_THREADS 10
  22 #define PREFETCH_CACHE_SIZE 1048576 //1MB
  23
  24 #define GET_NTUPLES(x)  ((int *)(x + sizeof(prefetchqelem_t)))
  25 #define GET_PTR_OID(x)  ((unsigned int *)(x + sizeof(prefetchqelem_t) + sizeof(int)))
  26 #define GET_PTR_EOFF(x,n) ((short *)(x + sizeof(prefetchqelem_t) + sizeof(int) + (n*sizeof(unsigned int))))
  27 #define GET_PTR_ARRYFLD(x,n) ((short *)(x + sizeof(prefetchqelem_t) + sizeof(int) + (n*sizeof(unsigned int)) + (n*sizeof(short))))
  28
  29 /* Global Variables */
  30 extern int classsize[];
  31 extern primarypfq_t pqueue; // shared prefetch queue
  32 pthread_t wthreads[NUM_THREADS]; //Worker threads for working on the prefetch queue
  33 pthread_t tPrefetch;
  34 extern objstr_t *mainobjstore;
  35 objstr_t *prefetchcache;
  36
  37 plistnode_t *createPiles(transrecord_t *);
  38 inline int arrayLength(int *array) {
  39         int i;
  40         for(i=0 ;array[i] != -1; i++)
  41                 ;
  42         return i;
  43 }
  44 /* This function is a prefetch call generated by the compiler that
  45  * populates the shared primary prefetch queue*/
  46 void prefetch(int ntuples, unsigned int *oids, short *endoffsets, short *arrayfields) {
  47         int qnodesize;
  48         int len = 0;
  49
  50         /* Allocate for the queue node*/
  51         char *node;
  52         qnodesize = sizeof(prefetchqelem_t) + sizeof(int) + ntuples * (sizeof(short) + sizeof(unsigned int)) + endoffsets[ntuples - 1] * sizeof(short);
  53         if((node = calloc(1,qnodesize)) == NULL) {
  54                 printf("Calloc Error %s, %d\n", __FILE__, __LINE__);
  55                 return;
  56         }
  57         /* Set queue node values */
  58         len = sizeof(prefetchqelem_t);
  59         memcpy(node + len, &ntuples, sizeof(int));
  60         len += sizeof(int);
  61         memcpy(node + len, oids, ntuples*sizeof(unsigned int));
  62         len += ntuples * sizeof(unsigned int);
  63         memcpy(node + len, endoffsets, ntuples*sizeof(short));
  64         len += ntuples * sizeof(short);
  65         memcpy(node + len, arrayfields, endoffsets[ntuples-1]*sizeof(short));
  66         /* Lock and insert into primary prefetch queue */
  67         pthread_mutex_lock(&pqueue.qlock);
  68         enqueue((prefetchqelem_t *)node);
  69         pthread_cond_signal(&pqueue.qcond);
  70         pthread_mutex_unlock(&pqueue.qlock);
  71 }
  72
  73 /* This function initiates the prefetch thread
  74  * A queue is shared between the main thread of execution
  75  * and the prefetch thread to process the prefetch call
  76  * Call from compiler populates the shared queue with prefetch requests while prefetch thread
  77  * processes the prefetch requests */
  78 void transInit() {
  79         int t, rc;
  80         //Create and initialize prefetch cache structure
  81         prefetchcache = objstrCreate(PREFETCH_CACHE_SIZE);
  82         //Create prefetch cache lookup table
  83         if(prehashCreate(HASH_SIZE, LOADFACTOR))
  84                         return; //Failure
  85         //Initialize primary shared queue
  86         queueInit();
  87         //Create the primary prefetch thread
  88         pthread_create(&tPrefetch, NULL, transPrefetch, NULL);
  89         //Create and Initialize a pool of threads
  90         for(t = 0; t< NUM_THREADS; t++) {
  91                 //rc = pthread_create(&wthreads[t], NULL, pfqProcess, (void *)t);
  92                 if (rc) {
  93                         printf("Thread create error %s, %d\n", __FILE__, __LINE__);
  94                         return;
  95                 }
  96         }
  97 }
  98
  99 /* This function stops the threads spawned */
 100 void transExit() {
 101         int t;
 102         pthread_cancel(tPrefetch);
 103         for(t = 0; t < NUM_THREADS; t++)
 104                 pthread_cancel(wthreads[t]);
 105
 106         return;
 107 }
 108
 109 /* This functions inserts randowm wait delays in the order of msec
 110  * Mostly used when transaction commits retry*/
 111 void randomdelay(void)
 112 {
 113         struct timespec req, rem;
 114         time_t t;
 115
 116         t = time(NULL);
 117         req.tv_sec = 0;
 118         req.tv_nsec = (long)(1000000 + (t%10000000)); //1-11 msec
 119         nanosleep(&req, &rem);
 120         return;
 121 }
 122
 123 /* This function initializes things required in the transaction start*/
 124 transrecord_t *transStart()
 125 {
 126         transrecord_t *tmp = malloc(sizeof(transrecord_t));
 127         tmp->cache = objstrCreate(1048576);
 128         tmp->lookupTable = chashCreate(HASH_SIZE, LOADFACTOR);
 129
 130         return tmp;
 131 }
 132
 133 /* This function finds the location of the objects involved in a transaction
 134  * and returns the pointer to the object if found in a remote location */
 135 objheader_t *transRead(transrecord_t *record, unsigned int oid)
 136 {
 137         unsigned int machinenumber;
 138         objheader_t *tmp, *objheader;
 139         void *objcopy;
 140         int size;
 141         void *buf;
 142                 /* Search local cache */
 143         if((objheader = (objheader_t *)chashSearch(record->lookupTable, oid)) != NULL){
 144                 return(objheader);
 145         } else if ((objheader = (objheader_t *) mhashSearch(oid)) != NULL) {
 146                 /* Look up in machine lookup table  and copy  into cache*/
 147 //              tmp = mhashSearch(oid);
 148                 size = sizeof(objheader_t)+classsize[tmp->type];
 149                 objcopy = objstrAlloc(record->cache, size);
 150                 memcpy(objcopy, (void *)objheader, size);
 151                 /* Insert into cache's lookup table */
 152                 chashInsert(record->lookupTable, objheader->oid, objcopy);
 153                 return(objcopy);
 154         } else { /* If not found in machine look up */
 155                 /* Get the object from the remote location */
 156                 machinenumber = lhashSearch(oid);
 157                 objcopy = getRemoteObj(record, machinenumber, oid);
 158                 if(objcopy == NULL) {
 159                         //If object is not found in Remote location
 160                         //printf("Object oid = %d not found in Machine %d\n", oid, machinenumber);
 161                         return NULL;
 162                 }
 163                 else {
 164                         //printf("Object oid = %d found in Machine %d\n", oid, machinenumber);
 165                         return(objcopy);
 166                 }
 167         }
 168 }
 169
 170 /* This function creates objects in the transaction record */
 171 objheader_t *transCreateObj(transrecord_t *record, unsigned short type)
 172 {
 173         objheader_t *tmp = (objheader_t *) objstrAlloc(record->cache, (sizeof(objheader_t) + classsize[type]));
 174         tmp->oid = getNewOID();
 175         tmp->type = type;
 176         tmp->version = 1;
 177         tmp->rcount = 0; //? not sure how to handle this yet
 178         tmp->status = 0;
 179         tmp->status |= NEW;
 180         chashInsert(record->lookupTable, tmp->oid, tmp);
 181         return tmp;
 182 }
 183
 184 /* This function creates machine piles based on all machines involved in a
 185  * transaction commit request */
 186 plistnode_t *createPiles(transrecord_t *record) {
 187         int i = 0;
 188         unsigned int size;/* Represents number of bins in the chash table */
 189         chashlistnode_t *curr, *ptr, *next;
 190         plistnode_t *pile = NULL;
 191         unsigned int machinenum;
 192         void *localmachinenum;
 193         objheader_t *headeraddr;
 194
 195         ptr = record->lookupTable->table;
 196         size = record->lookupTable->size;
 197
 198         for(i = 0; i < size ; i++) {
 199                 curr = &ptr[i];
 200                 /* Inner loop to traverse the linked list of the cache lookupTable */
 201                 while(curr != NULL) {
 202                         //if the first bin in hash table is empty
 203                         if(curr->key == 0) {
 204                                 break;
 205                         }
 206                         next = curr->next;
 207                         //Get machine location for object id
 208
 209                         if ((machinenum = lhashSearch(curr->key)) == 0) {
 210                                printf("Error: No such machine %s, %d\n", __FILE__, __LINE__);
 211                                return NULL;
 212                         }
 213
 214                         if ((headeraddr = chashSearch(record->lookupTable, curr->key)) == NULL) {
 215                                 printf("Error: No such oid %s, %d\n", __FILE__, __LINE__);
 216                                 return NULL;
 217                         }
 218                         //Make machine groups
 219                         if ((pile = pInsert(pile, headeraddr, machinenum, record->lookupTable->numelements)) == NULL) {
 220                                 printf("pInsert error %s, %d\n", __FILE__, __LINE__);
 221                                 return NULL;
 222                         }
 223
 224                         /* Check if local or not */
 225                         if((localmachinenum = mhashSearch(curr->key)) != NULL) {
 226                                 pile->local = 1; //True i.e. local
 227                         }
 228
 229                         curr = next;
 230                 }
 231         }
 232         return pile;
 233 }
 234
 235 /* This function initiates the transaction commit process
 236  * Spawns threads for each of the new connections with Participants
 237  * and creates new piles by calling the createPiles(),
 238  * Fills the piles with necesaary information and
 239  * Sends a transrequest() to each pile*/
 240 int transCommit(transrecord_t *record) {
 241         unsigned int tot_bytes_mod, *listmid;
 242         plistnode_t *pile;
 243         int i, rc, val;
 244         int pilecount = 0, offset, threadnum = 0, trecvcount = 0, tmachcount = 0;
 245         char buffer[RECEIVE_BUFFER_SIZE],control;
 246         char transid[TID_LEN];
 247         trans_req_data_t *tosend;
 248         trans_commit_data_t transinfo;
 249         static int newtid = 0;
 250         char treplyctrl = 0, treplyretry = 0; /* keeps track of the common response that needs to be sent */
 251         char localstat = 0;
 252
 253         /* Look through all the objects in the transaction record and make piles
 254          * for each machine involved in the transaction*/
 255         pile = createPiles(record);
 256
 257         /* Create the packet to be sent in TRANS_REQUEST */
 258
 259         /* Count the number of participants */
 260         pilecount = pCount(pile);
 261
 262         /* Create a list of machine ids(Participants) involved in transaction   */
 263         if((listmid = calloc(pilecount, sizeof(unsigned int))) == NULL) {
 264                 printf("Calloc error %s, %d\n", __FILE__, __LINE__);
 265                 return 1;
 266         }
 267         pListMid(pile, listmid);
 268
 269
 270         /* Initialize thread variables,
 271          * Spawn a thread for each Participant involved in a transaction */
 272         pthread_t thread[pilecount];
 273         pthread_attr_t attr;
 274         pthread_cond_t tcond;
 275         pthread_mutex_t tlock;
 276         pthread_mutex_t tlshrd;
 277
 278         thread_data_array_t *thread_data_array;
 279         thread_data_array = (thread_data_array_t *) malloc(sizeof(thread_data_array_t)*pilecount);
 280         local_thread_data_array_t *ltdata;
 281         if((ltdata = calloc(1, sizeof(local_thread_data_array_t))) == NULL) {
 282                 printf("Calloc error %s, %d\n", __FILE__, __LINE__);
 283                 return 1;
 284         }
 285
 286         thread_response_t rcvd_control_msg[pilecount];  /* Shared thread array that keeps track of responses of participants */
 287
 288         /* Initialize and set thread detach attribute */
 289         pthread_attr_init(&attr);
 290         pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
 291         pthread_mutex_init(&tlock, NULL);
 292         pthread_cond_init(&tcond, NULL);
 293
 294         /* Process each machine pile */
 295         while(pile != NULL) {
 296                 //Create transaction id
 297                 newtid++;
 298                 //trans_req_data_t *tosend;
 299                 if ((tosend = calloc(1, sizeof(trans_req_data_t))) == NULL) {
 300                         printf("Calloc error %s, %d\n", __FILE__, __LINE__);
 301                         return 1;
 302                 }
 303                 tosend->f.control = TRANS_REQUEST;
 304                 sprintf(tosend->f.trans_id, "%x_%d", pile->mid, newtid);
 305                 tosend->f.mcount = pilecount;
 306                 tosend->f.numread = pile->numread;
 307                 tosend->f.nummod = pile->nummod;
 308                 tosend->f.sum_bytes = pile->sum_bytes;
 309                 tosend->listmid = listmid;
 310                 tosend->objread = pile->objread;
 311                 tosend->oidmod = pile->oidmod;
 312                 thread_data_array[threadnum].thread_id = threadnum;
 313                 thread_data_array[threadnum].mid = pile->mid;
 314                 thread_data_array[threadnum].pilecount = pilecount;
 315                 thread_data_array[threadnum].buffer = tosend;
 316                 thread_data_array[threadnum].recvmsg = rcvd_control_msg;
 317                 thread_data_array[threadnum].threshold = &tcond;
 318                 thread_data_array[threadnum].lock = &tlock;
 319                 thread_data_array[threadnum].count = &trecvcount;
 320                 thread_data_array[threadnum].replyctrl = &treplyctrl;
 321                 thread_data_array[threadnum].replyretry = &treplyretry;
 322                 thread_data_array[threadnum].rec = record;
 323                 /* If local do not create any extra connection */
 324                 if(pile->local != 1) { /* Not local */
 325                         rc = pthread_create(&thread[threadnum], NULL, transRequest, (void *) &thread_data_array[threadnum]);
 326                         if (rc) {
 327                                 perror("Error in pthread create\n");
 328                                 return 1;
 329                         }
 330                 } else { /*Local*/
 331                         /*Unset the pile->local flag*/
 332                         pile->local = 0;
 333                         /*Set flag to identify that Local machine is involved*/
 334                         ltdata->tdata = &thread_data_array[threadnum];
 335                         ltdata->transinfo = &transinfo;
 336                         val = pthread_create(&thread[threadnum], NULL, handleLocalReq, (void *) ltdata);
 337                         if (val) {
 338                                 perror("Error in pthread create\n");
 339                                 return 1;
 340                         }
 341                 }
 342                 threadnum++;
 343                 pile = pile->next;
 344         }
 345
 346         /* Free attribute and wait for the other threads */
 347         pthread_attr_destroy(&attr);
 348         for (i = 0 ;i < pilecount ; i++) {
 349                 rc = pthread_join(thread[i], NULL);
 350                 if (rc)
 351                 {
 352                         printf("ERROR return code from pthread_join() is %d\n", rc);
 353                         return 1;
 354                 }
 355         }
 356
 357         /* Free resources */
 358         pthread_cond_destroy(&tcond);
 359         pthread_mutex_destroy(&tlock);
 360         free(tosend);
 361         free(listmid);
 362         pDelete(pile);
 363         free(thread_data_array);
 364         free(ltdata);
 365
 366         /* Retry trans commit procedure if not sucessful in the first try */
 367         if(treplyretry == 1) {
 368                 /* wait a random amount of time */
 369                 randomdelay();
 370                 //sleep(1);
 371                 /* Retry the commiting transaction again */
 372                 transCommit(record);
 373         }
 374
 375         return 0;
 376 }
 377
 378 /* This function sends information involved in the transaction request and
 379  * accepts a response from particpants.
 380  * It calls decideresponse() to decide on what control message
 381  * to send next and sends the message using sendResponse()*/
 382 void *transRequest(void *threadarg) {
 383         int sd, i, n;
 384         struct sockaddr_in serv_addr;
 385         struct hostent *server;
 386         thread_data_array_t *tdata;
 387         objheader_t *headeraddr;
 388         char buffer[RECEIVE_BUFFER_SIZE], control, recvcontrol;
 389         char machineip[16], retval;
 390
 391         tdata = (thread_data_array_t *) threadarg;
 392
 393         /* Send Trans Request */
 394         if ((sd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
 395                 perror("Error in socket for TRANS_REQUEST\n");
 396                 return NULL;
 397         }
 398         bzero((char*) &serv_addr, sizeof(serv_addr));
 399         serv_addr.sin_family = AF_INET;
 400         serv_addr.sin_port = htons(LISTEN_PORT);
 401         midtoIP(tdata->mid,machineip);
 402         machineip[15] = '\0';
 403         serv_addr.sin_addr.s_addr = inet_addr(machineip);
 404         /* Open Connection */
 405         if (connect(sd, (struct sockaddr *) &serv_addr, sizeof(struct sockaddr)) < 0) {
 406                 perror("Error in connect for TRANS_REQUEST\n");
 407                 return NULL;
 408         }
 409
 410         printf("DEBUG-> trans.c Sending TRANS_REQUEST to mid %s\n", machineip);
 411         /* Send bytes of data with TRANS_REQUEST control message */
 412         if (send(sd, &(tdata->buffer->f), sizeof(fixed_data_t),MSG_NOSIGNAL) < sizeof(fixed_data_t)) {
 413                 perror("Error sending fixed bytes for thread\n");
 414                 return NULL;
 415         }
 416         /* Send list of machines involved in the transaction */
 417         {
 418           int size=sizeof(unsigned int)*tdata->pilecount;
 419           if (send(sd, tdata->buffer->listmid, size, MSG_NOSIGNAL) < size) {
 420             perror("Error sending list of machines for thread\n");
 421             return NULL;
 422           }
 423         }
 424         /* Send oids and version number tuples for objects that are read */
 425         {
 426           int size=(sizeof(unsigned int)+sizeof(short))*tdata->buffer->f.numread;
 427           if (send(sd, tdata->buffer->objread, size, MSG_NOSIGNAL) < size) {
 428             perror("Error sending tuples for thread\n");
 429             return NULL;
 430           }
 431         }
 432         /* Send objects that are modified */
 433         for(i = 0; i < tdata->buffer->f.nummod ; i++) {
 434           int size;
 435           headeraddr = chashSearch(tdata->rec->lookupTable, tdata->buffer->oidmod[i]);
 436           size=sizeof(objheader_t)+classsize[headeraddr->type];
 437           if (send(sd, headeraddr, size, MSG_NOSIGNAL)  < size) {
 438             perror("Error sending obj modified for thread\n");
 439             return NULL;
 440           }
 441         }
 442
 443         /* Read control message from Participant */
 444         if((n = read(sd, &control, sizeof(char))) <= 0) {
 445                 perror("Error in reading control message from Participant\n");
 446                 return NULL;
 447         }
 448         recvcontrol = control;
 449
 450         /* Update common data structure and increment count */
 451         tdata->recvmsg[tdata->thread_id].rcv_status = recvcontrol;
 452
 453         /* Lock and update count */
 454         //Thread sleeps until all messages from pariticipants are received by coordinator
 455         pthread_mutex_lock(tdata->lock);
 456
 457         (*(tdata->count))++; /* keeps track of no of messages received by the coordinator */
 458
 459         /* Wake up the threads and invoke decideResponse (once) */
 460         if(*(tdata->count) == tdata->pilecount) {
 461                 if (decideResponse(tdata) != 0) {
 462                         printf("decideResponse returned error %s,%d\n", __FILE__, __LINE__);
 463                         pthread_mutex_unlock(tdata->lock);
 464                         close(sd);
 465                         return NULL;
 466                 }
 467                 pthread_cond_broadcast(tdata->threshold);
 468         } else {
 469                 pthread_cond_wait(tdata->threshold, tdata->lock);
 470         }
 471         pthread_mutex_unlock(tdata->lock);
 472
 473         /* Send the final response such as TRANS_COMMIT or TRANS_ABORT t
 474          * to all participants in their respective socket */
 475         if (sendResponse(tdata, sd) == 0) {
 476                 printf("sendResponse returned error %s,%d\n", __FILE__, __LINE__);
 477                 pthread_mutex_unlock(tdata->lock);
 478                 close(sd);
 479                 return NULL;
 480         }
 481
 482         /* Close connection */
 483         close(sd);
 484         pthread_exit(NULL);
 485 }
 486
 487 /* This function decides the reponse that needs to be sent to
 488  * all Participant machines involved in the transaction commit */
 489 int decideResponse(thread_data_array_t *tdata) {
 490         char control;
 491         int i, transagree = 0, transdisagree = 0, transsoftabort = 0; /* Counters to formulate decision of what
 492                                                                          message to send */
 493
 494         //Check common data structure
 495         for (i = 0 ; i < tdata->pilecount ; i++) {
 496                 /*Switch on response from Participant */
 497                 control = tdata->recvmsg[i].rcv_status; /* tdata: keeps track of all participant responses
 498                                                            written onto the shared array */
 499                 switch(control) {
 500                         case TRANS_DISAGREE:
 501                                 printf("DEBUG-> trans.c Recv TRANS_DISAGREE\n");
 502                                 transdisagree++;
 503                                 break;
 504
 505                         case TRANS_AGREE:
 506                                 printf("DEBUG-> trans.c Recv TRANS_AGREE\n");
 507                                 transagree++;
 508                                 break;
 509
 510                         case TRANS_SOFT_ABORT:
 511                                 printf("DEBUG-> trans.c Recv TRANS_SOFT_ABORT\n");
 512                                 transsoftabort++;
 513                                 break;
 514                         default:
 515                                 printf("Participant sent unknown message in %s, %d\n", __FILE__, __LINE__);
 516                                 return -1;
 517                 }
 518         }
 519
 520         /* Decide what control message to send to Participant */
 521         if(transdisagree > 0) {
 522                 /* Send Abort */
 523                 *(tdata->replyctrl) = TRANS_ABORT;
 524                 printf("DEBUG-> trans.c Sending TRANS_ABORT\n");
 525                 objstrDelete(tdata->rec->cache);
 526                 chashDelete(tdata->rec->lookupTable);
 527                 free(tdata->rec);
 528         } else if(transagree == tdata->pilecount){
 529                 /* Send Commit */
 530                 *(tdata->replyctrl) = TRANS_COMMIT;
 531                 printf("DEBUG-> trans.c Sending TRANS_COMMIT\n");
 532                 objstrDelete(tdata->rec->cache);
 533                 chashDelete(tdata->rec->lookupTable);
 534                 free(tdata->rec);
 535         } else if(transsoftabort > 0 && transdisagree == 0) {
 536                 /* Send Abort in soft abort case followed by retry commiting transaction again*/
 537                 *(tdata->replyctrl) = TRANS_ABORT;
 538                 *(tdata->replyretry) = 1;
 539                 printf("DEBUG-> trans.c Sending TRANS_ABORT\n");
 540         } else {
 541                 printf("DEBUG -> %s, %d: Error: undecided response\n", __FILE__, __LINE__);
 542                 return -1;
 543         }
 544
 545         return 0;
 546 }
 547 /* This function sends the final response to all threads in their respective socket id */
 548 char sendResponse(thread_data_array_t *tdata, int sd) {
 549         int n, N, sum, oidcount = 0;
 550         char *ptr, retval = 0;
 551         unsigned int *oidnotfound;
 552
 553         /* If the decided response is due to a soft abort and missing objects at the Participant's side */
 554         if(tdata->recvmsg[tdata->thread_id].rcv_status == TRANS_SOFT_ABORT) {
 555                 /* Read list of objects missing */
 556                 if((read(sd, &oidcount, sizeof(int)) != 0) && (oidcount != 0)) {
 557                         N = oidcount * sizeof(unsigned int);
 558                         if((oidnotfound = calloc(oidcount, sizeof(unsigned int))) == NULL) {
 559                                 printf("Calloc error %s, %d\n", __FILE__, __LINE__);
 560                         }
 561                         ptr = (char *) oidnotfound;
 562                         do {
 563                                 n = read(sd, ptr+sum, N-sum);
 564                                 sum += n;
 565                         } while(sum < N && n !=0);
 566                 }
 567                 retval =  TRANS_SOFT_ABORT;
 568         }
 569         /* If the decided response is TRANS_ABORT */
 570         if(*(tdata->replyctrl) == TRANS_ABORT) {
 571                 retval = TRANS_ABORT;
 572         } else if(*(tdata->replyctrl) == TRANS_COMMIT) { /* If the decided response is TRANS_COMMIT */
 573                 retval = TRANS_COMMIT;
 574         }
 575         /* Send response to the Participant */
 576         if (send(sd, tdata->replyctrl, sizeof(char),MSG_NOSIGNAL) < sizeof(char)) {
 577                 perror("Error sending ctrl message for participant\n");
 578         }
 579
 580         return retval;
 581 }
 582
 583 /* This function opens a connection, places an object read request to the
 584  * remote machine, reads the control message and object if available  and
 585  * copies the object and its header to the local cache.
 586  * TODO replace mnum and midtoIP() with MACHINE_IP address later */
 587
 588 void *getRemoteObj(transrecord_t *record, unsigned int mnum, unsigned int oid) {
 589         int sd, size, val;
 590         struct sockaddr_in serv_addr;
 591         struct hostent *server;
 592         char control;
 593         char machineip[16];
 594         objheader_t *h;
 595         void *objcopy;
 596
 597         if ((sd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
 598                 perror("Error in socket\n");
 599                 return NULL;
 600         }
 601         bzero((char*) &serv_addr, sizeof(serv_addr));
 602         serv_addr.sin_family = AF_INET;
 603         serv_addr.sin_port = htons(LISTEN_PORT);
 604         //serv_addr.sin_addr.s_addr = inet_addr(MACHINE_IP);
 605         midtoIP(mnum,machineip);
 606         machineip[15] = '\0';
 607         serv_addr.sin_addr.s_addr = inet_addr(machineip);
 608         /* Open connection */
 609         if (connect(sd, (struct sockaddr *) &serv_addr, sizeof(struct sockaddr)) < 0) {
 610                 perror("Error in connect\n");
 611                 return NULL;
 612         }
 613         char readrequest[sizeof(char)+sizeof(unsigned int)];
 614         readrequest[0] = READ_REQUEST;
 615         *((unsigned int *)(&readrequest[1])) = oid;
 616         if (send(sd, &readrequest, sizeof(readrequest), MSG_NOSIGNAL) < sizeof(readrequest)) {
 617                 perror("Error sending message\n");
 618                 return NULL;
 619         }
 620
 621 #ifdef DEBUG1
 622         printf("DEBUG -> ready to rcv ...\n");
 623 #endif
 624         /* Read response from the Participant */
 625         if((val = read(sd, &control, sizeof(char))) <= 0) {
 626                 perror("No control response for getRemoteObj sent\n");
 627                 return NULL;
 628         }
 629         switch(control) {
 630                 case OBJECT_NOT_FOUND:
 631                         printf("DEBUG -> Control OBJECT_NOT_FOUND received\n");
 632                         return NULL;
 633                 case OBJECT_FOUND:
 634                         /* Read object if found into local cache */
 635                         if((val = read(sd, &size, sizeof(int))) <= 0) {
 636                                 perror("No size is read from the participant\n");
 637                                 return NULL;
 638                         }
 639                         objcopy = objstrAlloc(record->cache, size);
 640                         if((val = read(sd, objcopy, size)) <= 0) {
 641                                 perror("No objects are read from the remote participant\n");
 642                                 return NULL;
 643                         }
 644                         /* Insert into cache's lookup table */
 645                         chashInsert(record->lookupTable, oid, objcopy);
 646                         break;
 647                 default:
 648                         printf("Error in recv request from participant on a READ_REQUEST %s, %d\n",__FILE__, __LINE__);
 649                         return NULL;
 650         }
 651         /* Close connection */
 652         close(sd);
 653         return objcopy;
 654 }
 655
 656 /*This function handles the local trans requests involved in a transaction commiting process
 657  * makes a decision if the local machine sends AGREE or DISAGREE or SOFT_ABORT
 658  * Activates the other nonlocal threads that are waiting for the decision and the
 659  * based on common decision by all groups involved in the transaction it
 660  * either commits or aborts the transaction.
 661  * It also frees the calloced memory resources
 662  */
 663
 664 void *handleLocalReq(void *threadarg) {
 665         int val, i = 0;
 666         short version;
 667         char control = 0, *ptr;
 668         unsigned int oid;
 669         unsigned int *oidnotfound = NULL, *oidlocked = NULL, *oidmod = NULL;
 670         void *mobj, *modptr;
 671         objheader_t *headptr;
 672         local_thread_data_array_t *localtdata;
 673
 674         localtdata = (local_thread_data_array_t *) threadarg;
 675
 676         /* Counters and arrays to formulate decision on control message to be sent */
 677         oidnotfound = (unsigned int *) calloc((localtdata->tdata->buffer->f.numread + localtdata->tdata->buffer->f.nummod), sizeof(unsigned int));
 678         oidlocked = (unsigned int *) calloc((localtdata->tdata->buffer->f.numread + localtdata->tdata->buffer->f.nummod), sizeof(unsigned int));
 679         oidmod = (unsigned int *) calloc(localtdata->tdata->buffer->f.nummod, sizeof(unsigned int));
 680         int objnotfound = 0, objlocked = 0, objmod =0, v_nomatch = 0, v_matchlock = 0, v_matchnolock = 0;
 681         int objmodnotfound = 0, nummodfound = 0;
 682
 683         /* modptr points to the beginning of the object store
 684          * created at the Pariticipant */
 685         if ((modptr = objstrAlloc(mainobjstore, localtdata->tdata->buffer->f.sum_bytes)) == NULL) {
 686                 printf("objstrAlloc error for modified objects %s, %d\n", __FILE__, __LINE__);
 687                 return NULL;
 688         }
 689
 690         ptr = modptr;
 691
 692         /* Process each oid in the machine pile/ group per thread */
 693         for (i = 0; i < localtdata->tdata->buffer->f.numread + localtdata->tdata->buffer->f.nummod; i++) {
 694                 if (i < localtdata->tdata->buffer->f.numread) {//Objs only read and not modified
 695                         int incr = sizeof(unsigned int) + sizeof(short);// Offset that points to next position in the objread array
 696                         incr *= i;
 697                         oid = *((unsigned int *)(localtdata->tdata->buffer->objread + incr));
 698                         incr += sizeof(unsigned int);
 699                         version = *((short *)(localtdata->tdata->buffer->objread + incr));
 700                 } else {//Objs modified
 701                         headptr = (objheader_t *) ptr;
 702                         oid = headptr->oid;
 703                         oidmod[objmod] = oid;//Array containing modified oids
 704                         objmod++;
 705                         version = headptr->version;
 706                         ptr += sizeof(objheader_t) + classsize[headptr->type];
 707                 }
 708
 709                 /* Check if object is still present in the machine since the beginning of TRANS_REQUEST */
 710
 711                 /* Save the oids not found and number of oids not found for later use */
 712                 if ((mobj = mhashSearch(oid)) == NULL) {/* Obj not found */
 713                         /* Save the oids not found and number of oids not found for later use */
 714
 715                         oidnotfound[objnotfound] = ((objheader_t *)mobj)->oid;
 716                         objnotfound++;
 717                 } else { /* If Obj found in machine (i.e. has not moved) */
 718                         /* Check if Obj is locked by any previous transaction */
 719                         if ((((objheader_t *)mobj)->status & LOCK) == LOCK) {
 720                                 if (version == ((objheader_t *)mobj)->version) {      /* If not locked then match versions */
 721                                         v_matchlock++;
 722                                 } else {/* If versions don't match ...HARD ABORT */
 723                                         v_nomatch++;
 724                                         /* Send TRANS_DISAGREE to Coordinator */
 725                                         localtdata->tdata->recvmsg[localtdata->tdata->thread_id].rcv_status = TRANS_DISAGREE;
 726                                         printf("DEBUG -> Sending TRANS_DISAGREE\n");
 727                                         //return tdata->recvmsg[tdata->thread_id].rcv_status;
 728                                 }
 729                         } else {/* If Obj is not locked then lock object */
 730                                 ((objheader_t *)mobj)->status |= LOCK;
 731                                 //TODO Remove this for Testing
 732                                 randomdelay();
 733
 734                                 /* Save all object oids that are locked on this machine during this transaction request call */
 735                                 oidlocked[objlocked] = ((objheader_t *)mobj)->oid;
 736                                 objlocked++;
 737                                 if (version == ((objheader_t *)mobj)->version) { /* Check if versions match */
 738                                         v_matchnolock++;
 739                                 } else { /* If versions don't match ...HARD ABORT */
 740                                         v_nomatch++;
 741                                         /* Send TRANS_DISAGREE to Coordinator */
 742                                         localtdata->tdata->recvmsg[localtdata->tdata->thread_id].rcv_status = TRANS_DISAGREE;
 743                                         printf("DEBUG -> Sending TRANS_DISAGREE\n");
 744                                 //      return tdata->recvmsg[tdata->thread_id].rcv_status;
 745                                 }
 746                         }
 747                 }
 748         }
 749
 750         /*Decide the response to be sent to the Coordinator( the local machine in this case)*/
 751
 752         /* Condition to send TRANS_AGREE */
 753         if(v_matchnolock == localtdata->tdata->buffer->f.numread + localtdata->tdata->buffer->f.nummod) {
 754                 localtdata->tdata->recvmsg[localtdata->tdata->thread_id].rcv_status = TRANS_AGREE;
 755                 printf("DEBUG -> Sending TRANS_AGREE\n");
 756         }
 757         /* Condition to send TRANS_SOFT_ABORT */
 758         if((v_matchlock > 0 && v_nomatch == 0) || (objnotfound > 0 && v_nomatch == 0)) {
 759                 localtdata->tdata->recvmsg[localtdata->tdata->thread_id].rcv_status = TRANS_SOFT_ABORT;
 760                 printf("DEBUG -> Sending TRANS_SOFT_ABORT\n");
 761                 /* Send number of oids not found and the missing oids if objects are missing in the machine */
 762                 /* TODO Remember to store the oidnotfound for later use
 763                 if(objnotfound != 0) {
 764                         int size = sizeof(unsigned int)* objnotfound;
 765                 }
 766                 */
 767         }
 768
 769         /* Fill out the trans_commit_data_t data structure. This is required for a trans commit process
 770          * if Participant receives a TRANS_COMMIT */
 771         localtdata->transinfo->objmod = oidmod;
 772         localtdata->transinfo->objlocked = oidlocked;
 773         localtdata->transinfo->objnotfound = oidnotfound;
 774         localtdata->transinfo->modptr = modptr;
 775         localtdata->transinfo->nummod = localtdata->tdata->buffer->f.nummod;
 776         localtdata->transinfo->numlocked = objlocked;
 777         localtdata->transinfo->numnotfound = objnotfound;
 778
 779         /*Set flag to show that common data structure for this individual thread has been written to */
 780         //*(tdata->localstatus) |= LM_UPDATED;
 781
 782         /* Lock and update count */
 783         //Thread sleeps until all messages from pariticipants are received by coordinator
 784         pthread_mutex_lock(localtdata->tdata->lock);
 785         (*(localtdata->tdata->count))++; /* keeps track of no of messages received by the coordinator */
 786
 787         /* Wake up the threads and invoke decideResponse (once) */
 788         if(*(localtdata->tdata->count) == localtdata->tdata->pilecount) {
 789                 if (decideResponse(localtdata->tdata) != 0) {
 790                         printf("decideResponse returned error %s,%d\n", __FILE__, __LINE__);
 791                         pthread_mutex_unlock(localtdata->tdata->lock);
 792                         return NULL;
 793                 }
 794                 pthread_cond_broadcast(localtdata->tdata->threshold);
 795         } else {
 796                 pthread_cond_wait(localtdata->tdata->threshold, localtdata->tdata->lock);
 797         }
 798         pthread_mutex_unlock(localtdata->tdata->lock);
 799
 800         /*Based on DecideResponse(), Either COMMIT or ABORT the operation*/
 801         if(*(localtdata->tdata->replyctrl) == TRANS_ABORT){
 802                 if(transAbortProcess(modptr,oidlocked, localtdata->transinfo->numlocked, localtdata->transinfo->nummod, localtdata->tdata->buffer->f.numread) != 0) {
 803                         printf("Error in transAbortProcess() %s,%d\n", __FILE__, __LINE__);
 804                         return NULL;
 805                 }
 806         }else if(*(localtdata->tdata->replyctrl) == TRANS_COMMIT){
 807                 if(transComProcess(localtdata->transinfo) != 0) {
 808                         printf("Error in transComProcess() %s,%d\n", __FILE__, __LINE__);
 809                         return NULL;
 810                 }
 811         }
 812
 813         /* Free memory */
 814         printf("DEBUG -> Freeing...\n");
 815         fflush(stdout);
 816         if (localtdata->transinfo->objmod != NULL) {
 817                 free(localtdata->transinfo->objmod);
 818                 localtdata->transinfo->objmod = NULL;
 819         }
 820         if (localtdata->transinfo->objlocked != NULL) {
 821                 free(localtdata->transinfo->objlocked);
 822                 localtdata->transinfo->objlocked = NULL;
 823         }
 824         if (localtdata->transinfo->objnotfound != NULL) {
 825                 free(localtdata->transinfo->objnotfound);
 826                 localtdata->transinfo->objnotfound = NULL;
 827         }
 828
 829         pthread_exit(NULL);
 830 }
 831 /* This function completes the ABORT process if the transaction is aborting
 832  */
 833 int transAbortProcess(void *modptr, unsigned int *objlocked, int numlocked, int nummod, int numread) {
 834         char *ptr;
 835         int i;
 836         objheader_t *tmp_header;
 837         void *header;
 838
 839         printf("DEBUG -> Recv TRANS_ABORT\n");
 840         /* Set all ref counts as 1 and do garbage collection */
 841         ptr = modptr;
 842         for(i = 0; i< nummod; i++) {
 843                 tmp_header = (objheader_t *)ptr;
 844                 tmp_header->rcount = 1;
 845                 ptr += sizeof(objheader_t) + classsize[tmp_header->type];
 846         }
 847         /* Unlock objects that was locked due to this transaction */
 848         for(i = 0; i< numlocked; i++) {
 849                 header = mhashSearch(objlocked[i]);// find the header address
 850                 ((objheader_t *)header)->status &= ~(LOCK);
 851         }
 852         //TODO/* Unset the bit for local objects */
 853
 854         /* Send ack to Coordinator */
 855         printf("DEBUG-> TRANS_SUCCESSFUL\n");
 856
 857         /*Free the pointer */
 858         ptr = NULL;
 859         return 0;
 860 }
 861
 862 /*This function completes the COMMIT process is the transaction is commiting
 863  */
 864  int transComProcess(trans_commit_data_t *transinfo) {
 865          objheader_t *header;
 866          int i = 0, offset = 0;
 867          char control;
 868
 869          printf("DEBUG -> Recv TRANS_COMMIT\n");
 870          /* Process each modified object saved in the mainobject store */
 871          for(i=0; i<transinfo->nummod; i++) {
 872                  if((header = (objheader_t *) mhashSearch(transinfo->objmod[i])) == NULL) {
 873                          printf("mhashsearch returns NULL at %s, %d\n", __FILE__, __LINE__);
 874                  }
 875                  /* Change reference count of older address and free space in objstr ?? */
 876                  header->rcount = 1; //TODO Not sure what would be the val
 877
 878                  /* Change ptr address in mhash table */
 879                  mhashRemove(transinfo->objmod[i]);
 880                  mhashInsert(transinfo->objmod[i], (transinfo->modptr + offset));
 881                  offset += sizeof(objheader_t) + classsize[header->type];
 882
 883                  /* Update object version number */
 884                  header = (objheader_t *) mhashSearch(transinfo->objmod[i]);
 885                  header->version += 1;
 886          }
 887
 888          /* Unlock locked objects */
 889          for(i=0; i<transinfo->numlocked; i++) {
 890                  header = (objheader_t *) mhashSearch(transinfo->objlocked[i]);
 891                  header->status &= ~(LOCK);
 892          }
 893
 894          //TODO Update location lookup table
 895          //TODO/* Unset the bit for local objects */
 896
 897          /* Send ack to Coordinator */
 898          printf("DEBUG-> TRANS_SUCESSFUL\n");
 899          return 0;
 900  }
 901
 902 /* This function is called by the thread calling transPrefetch */
 903 void *transPrefetch(void *prefdata) {
 904         int *offstarray = NULL;
 905         prefetchqelem_t *qnode;
 906
 907         while(1) {
 908                 /* lock mutex of primary prefetch queue */
 909                 pthread_mutex_lock(&pqueue.qlock);
 910                 /* while primary queue is empty, then wait */
 911                 while((pqueue.front == NULL) && (pqueue.rear == NULL)) {
 912                         pthread_cond_wait(&pqueue.qcond, &pqueue.qlock);
 913                 }
 914
 915                 /* dequeue node to create a machine piles and  finally unlock mutex */
 916                 if((qnode = dequeue()) == NULL) {
 917                         printf("Error: No node returned %s, %d\n", __FILE__, __LINE__);
 918                         return NULL;
 919                 }
 920                 pthread_mutex_unlock(&pqueue.qlock);
 921                 /* Reduce redundant prefetch requests */
 922                 /* Group Requests by where objects are located */
 923
 924
 925
 926         }
 927 }
 928
 929 /* This function checks if the prefetch oids are same and have same offsets
 930  * for case x.a.b and y.a.b where x and y have same oid's
 931  * or if a.b.c is a subset of x.b.c.d*/
 932 /* check for case where the generated request a.y.z or x.y.z.g then
 933  * prefetch needs to be generated for x.y.z.g  if oid of a and x are same*/
 934 void checkPrefetchTuples(prefetchqelem_t *node) {
 935         int i,j, count,k, sindex, index;
 936         char *ptr, *tmp;
 937         int ntuples, slength;
 938         unsigned int *oid;
 939         short *endoffsets, *arryfields;
 940
 941         /* Check for the case x.y.z and a.b.c are same oids */
 942         ptr = (char *) node;
 943         ntuples = *(GET_NTUPLES(ptr));
 944         oid = GET_PTR_OID(ptr);
 945         endoffsets = GET_PTR_EOFF(ptr, ntuples);
 946         arryfields = GET_PTR_ARRYFLD(ptr, ntuples);
 947         /* Find offset length for each tuple */
 948         int numoffset[ntuples];
 949         numoffset[0] = endoffsets[0];
 950         for(i = 1; i<ntuples; i++) {
 951                 numoffset[i] = endoffsets[i] - endoffsets[i-1];
 952         }
 953         /* Check for redundant tuples by comparing oids of each tuple */
 954         for(i = 0; i < ntuples; i++) {
 955                 if(oid[i] == -1)
 956                         continue;
 957                 for(j = i+1 ; j < ntuples; j++) {
 958                         if(oid[j] == -1)
 959                                 continue;
 960                         /*If oids of tuples match */
 961                         if (oid[i] == oid[j]) {
 962                                 /* Find the smallest offset length of two tuples*/
 963                                 if(numoffset[i] >  numoffset[j]){
 964                                         slength = numoffset[j];
 965                                         sindex = j;
 966                                 }
 967                                 else {
 968                                         slength = numoffset[i];
 969                                         sindex = i;
 970                                 }
 971
 972                                 /* Compare the offset values based on the current indices
 973                                  * break if they do not match
 974                                  * if all offset values match then pick the largest tuple*/
 975
 976                                 if(i == 0) {
 977                                         k = 0;
 978                                         index = endoffsets[j -1];
 979                                         for(count = 0; count < slength; count ++) {
 980                                                 if (arryfields[k] != arryfields[index]) {
 981                                                         break;
 982                                                 }
 983                                                 index++;
 984                                                 k++;
 985                                         }
 986                                 } else {
 987                                         printf("i = %d, j = %d\n", i, j);
 988                                         k = endoffsets[i-1];
 989                                         index = endoffsets[j-1];
 990                                         printf("Value of slength = %d\n", slength);
 991                                         for(count = 0; count < slength; count++) {
 992                                                 printf("Value of count =%d\n", count);
 993                                                 if(arryfields[k] != arryfields[index]) {
 994                                                         break;
 995                                                 }
 996                                                 index++;
 997                                                 k++;
 998                                         }
 999                                         printf("Value of count =%d\n", count);
1000                                 }
1001                                 printf("The value of sindex = %d\n", sindex);
1002
1003                                 if(slength == count) {
1004                                         printf("DEBUG-> Inside slength if %d\n", sindex);
1005                                         oid[sindex] = -1;
1006                                 }
1007                         }
1008                 }
1009         }
1010 }
1011
1012 void checkPreCache(prefetchqelem_t *node, int *numoffset, int counter, int loopcount, unsigned int objoid, int index, int iter, int oidnfound) {
1013         char *ptr, *tmp;
1014         int ntuples, i, k, flag;
1015         unsigned int * oid;
1016         short *endoffsets, *arryfields;
1017         objheader_t *header;
1018
1019         ptr = (char *) node;
1020         ntuples = *(GET_NTUPLES(ptr));
1021         oid = GET_PTR_OID(ptr);
1022         endoffsets = GET_PTR_EOFF(ptr, ntuples);
1023         arryfields = GET_PTR_ARRYFLD(ptr, ntuples);
1024
1025         if(oidnfound == 1) {
1026                 if((header = (objheader_t *) prehashSearch(objoid)) == NULL) {
1027                         return;
1028                 } else { //Found in Prefetch Cache
1029                         //TODO Decide if object is too old, if old remove from cache
1030                         tmp = (char *) header;
1031                         /* Check if any of the offset oid is available in the Prefetch cache */
1032                         for(i = counter; i < loopcount; i++) {
1033                                 objoid = *(tmp + sizeof(objheader_t) + arryfields[counter]);
1034                                 if((header = (objheader_t *)prehashSearch(objoid)) != NULL) {
1035                                         flag = 0;
1036                                 } else {
1037                                         flag = 1;
1038                                         break;
1039                                 }
1040                         }
1041                 }
1042         } else {
1043                 for(i = counter; i<loopcount; i++) {
1044                         if((header = (objheader_t *)prehashSearch(objoid)) != NULL) {
1045                                 tmp = (char *) header;
1046                                 objoid = *(tmp + sizeof(objheader_t) + arryfields[index]);
1047                                 flag = 0;
1048                                 index++;
1049                         } else {
1050                                 flag = 1;
1051                                 break;
1052                         }
1053                 }
1054         }
1055
1056         /* If oid not found locally or in prefetch cache then
1057          * assign the latest oid found as the new oid
1058          * and copy left over offsets into the arrayoffsetfieldarray*/
1059         oid[iter] = objoid;
1060         numoffset[iter] = numoffset[iter] - (i+1);
1061         if(iter == 0)
1062                 endoffsets[iter] = numoffset[iter];
1063         else
1064                 endoffsets[iter] = numoffset[iter] + endoffsets[iter - 1];
1065         for(k = 0; k < numoffset[iter] ; k++) {
1066                 arryfields[k] = arryfields[counter+1];
1067                 counter++;
1068         }
1069
1070         if(flag == 0) {
1071                 oid[iter] = -1;
1072                 numoffset[iter] = 0;
1073                 endoffsets[iter] = 0;
1074         }
1075 }
1076
1077 /* This function checks if the oids within the prefetch tuples are available locally.
1078  * If yes then makes the tuple invalid. If no then rearranges oid and offset values in
1079  * the prefetchqelem_t node to represent a new prefetch tuple */
1080 void foundLocal(prefetchqelem_t *node) {
1081         int ntuples,i, j, k, oidnfound = 0, index, flag;
1082         unsigned int *oid;
1083         unsigned int  objoid;
1084         char *ptr, *tmp;
1085         objheader_t *objheader;
1086         short *endoffsets, *arryfields;
1087
1088         ptr = (char *) node;
1089         ntuples = *(GET_NTUPLES(ptr));
1090         oid = GET_PTR_OID(ptr);
1091         endoffsets = GET_PTR_EOFF(ptr, ntuples);
1092         arryfields = GET_PTR_ARRYFLD(ptr, ntuples);
1093         /* Find offset length for each tuple */
1094         int numoffset[ntuples];//Number of offsets for each tuple
1095         numoffset[0] = endoffsets[0];
1096         for(i = 1; i<ntuples; i++) {
1097                 numoffset[i] = endoffsets[i] - endoffsets[i-1];
1098         }
1099         for(i = 0; i < ntuples; i++) {
1100                 if(oid[i] == -1)
1101                         continue;
1102                 /* If object found locally */
1103                 if((objheader = (objheader_t*) mhashSearch(oid[i])) != NULL) {
1104                         oidnfound = 0;
1105                         tmp = (char *) objheader;
1106                         /* Find the oid of its offset value */
1107                         if(i == 0)
1108                                 index = 0;
1109                         else
1110                                 index = endoffsets[i - 1];
1111                         for(j = 0 ; j < numoffset[i] ; j++) {
1112                                 objoid = *(tmp + sizeof(objheader_t) + arryfields[index]);
1113                                 index++;
1114                                 /*New offset oid not found */
1115                                 if((objheader = (objheader_t*) mhashSearch(objoid)) == NULL) {
1116                                         flag = 1;
1117                                         checkPreCache(node, numoffset, j, numoffset[i], objoid, index, i, oidnfound);
1118                                         break;
1119                                 } else
1120                                         flag = 0;
1121                         }
1122                         /*If oid not found locally then
1123                          *assign the latest oid found as the new oid
1124                          *and copy left over offsets into the arrayoffsetfieldarray*/
1125                         oid[i] = objoid;
1126                         numoffset[i] = numoffset[i] - (j+1);
1127                         if(i == 0)
1128                                 endoffsets[i] = numoffset[i];
1129                         else
1130                                 endoffsets[i] = numoffset[i] - endoffsets[i - 1];
1131                         for(k = 0; k < numoffset[i]; k++) {
1132                                 arryfields[k] = arryfields[j+1];
1133                                 j++;
1134                         }
1135                         /*If all offset oids are found locally,make the prefetch tuple invalid */
1136                         if(flag == 0) {
1137                                 oid[i] = -1;
1138                                 numoffset[i] = 0;
1139                                 endoffsets[i] = 0;
1140                         }
1141                 } else {
1142                         oidnfound = 1;
1143                         /* Look in Prefetch cache */
1144                         checkPreCache(node, numoffset, 0, numoffset[i], oid[i], 0, i, oidnfound);
1145                 }
1146
1147         }
1148 }
1149
1150 void makePreGroups(prefetchqelem_t *node) {
1151         char *ptr, *tmp;
1152         int ntuples, slength, i, machinenum;
1153         unsigned int *oid;
1154         short *endoffsets, *arryfields;
1155
1156
1157         /* Check for the case x.y.z and a.b.c are same oids */
1158         ptr = (char *) node;
1159         ntuples = *(GET_NTUPLES(ptr));
1160         oid = GET_PTR_OID(ptr);
1161         endoffsets = GET_PTR_EOFF(ptr, ntuples);
1162         arryfields = GET_PTR_ARRYFLD(ptr, ntuples);
1163         /* Find offset length for each tuple */
1164         int numoffset[ntuples];
1165         numoffset[0] = endoffsets[0];
1166         for(i = 1; i<ntuples; i++) {
1167                 numoffset[i] = endoffsets[i] - endoffsets[i-1];
1168         }
1169
1170         /* Check for redundant tuples by comparing oids of each tuple */
1171         for(i = 0; i < ntuples; i++) {
1172                 if(oid[i] == -1)
1173                         continue;
1174                 /* For each tuple make piles */
1175                 if ((machinenum = lhashSearch(oid[i])) == 0) {
1176                         printf("Error: No such Machine %s, %d\n", __FILE__, __LINE__);
1177                         return;
1178                 }
1179         }
1180
1181 }
1182
1183 /*This function is called by the thread that processes the
1184  * prefetch request makes piles to prefetch records and prefetches the oids from remote machines */
1185 int transPrefetchProcess(transrecord_t *record, int *arrayofoffset[], short numoids){
1186         int i, k = 0, rc;
1187         int arraylength[numoids];
1188         unsigned int machinenumber;
1189         objheader_t *tmp, *objheader;
1190         void *objcopy;
1191         int size;
1192         pthread_attr_t attr;
1193
1194         /* Given tuple find length of tuple*/
1195         for(i = 0; i < numoids ; i++) {
1196                 arraylength[i] = arrayLength(arrayofoffset[i]);
1197         }
1198
1199         /* Initialize and set thread attributes
1200          * Spawn a thread for each prefetch request sent*/
1201         pthread_t thread[numoids];
1202         pthread_attr_init(&attr);
1203         pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
1204
1205         /* Create  Machine Piles to send prefetch requests use threads*/
1206         for( i = 0 ; i< numoids ; i++) {
1207                 if(arrayofoffset[i][0] == -1)
1208                         continue;
1209                 else{
1210                         /* For each Pile in the machine send TRANS_PREFETCH */
1211                         //makePiles(arrayofoffset, numoids);
1212                         /* Fill thread data structure */
1213                         rc = pthread_create(&thread[i] , &attr, sendPrefetchReq, (void *) arrayofoffset[i]);
1214                         if (rc) {
1215                                 perror("Error in pthread create at transPrefetchProcess()\n");
1216                                 return 1;
1217                         }
1218
1219                 }
1220         }
1221
1222         /* Free attribute and wait to join other threads */
1223         for (i = 0 ;i < numoids ; i++) {
1224                 rc = pthread_join(thread[i], NULL);
1225                 if (rc) {
1226                         perror("Error pthread_join() in transPrefetchProcess()\n");
1227                         return 1;
1228                 }
1229         }
1230         pthread_attr_destroy(&attr);
1231
1232         return 0;
1233
1234 }
1235
1236 void *sendPrefetchReq(void *prefetchtuple) {
1237         int sd, i;
1238         struct sockaddr_in serv_addr;
1239         struct hostent *server;
1240         char buffer[RECEIVE_BUFFER_SIZE], control, recvcontrol;
1241         char machineip[16], retval;
1242
1243
1244         /* Send Trans Prefetch Request */
1245         if ((sd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
1246                 perror("Error in socket for TRANS_REQUEST\n");
1247                 return NULL;
1248         }
1249         bzero((char*) &serv_addr, sizeof(serv_addr));
1250         serv_addr.sin_family = AF_INET;
1251         serv_addr.sin_port = htons(LISTEN_PORT);
1252         //midtoIP(tdata->mid,machineip);
1253 //      machineip[15] = '\0';
1254 //      serv_addr.sin_addr.s_addr = inet_addr(machineip);
1255
1256         /* Open Connection */
1257         if (connect(sd, (struct sockaddr *) &serv_addr, sizeof(struct sockaddr)) < 0) {
1258                 perror("Error in connect for TRANS_REQUEST\n");
1259                 return NULL;
1260         }
1261
1262         close(sd);
1263         pthread_exit(NULL);
1264
1265 }