stasis-aries-wal/src/lladd/bufferManager.c

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---*/
/*******************************
 * $Id$
 *
 * implementation of the page buffer
 * *************************************************/

#include <config.h>
#include <lladd/common.h>
#include <latches.h>
#include <assert.h>

#include "page.h"

#include <lladd/bufferManager.h>
#include "blobManager.h"
#include <lladd/pageCache.h>

#include "pageFile.h"

/**
   Invariant: This lock should be held while updating lastFreepage, or
   while performing any operation that may decrease the amount of
   freespace in the page that lastFreepage refers to.  

   Since pageCompact and pageDeRalloc may only increase this value,
   they do not need to hold this lock.  Since bufferManager is the
   only place where pageRalloc is called, pageRalloc does not obtain
   this lock.
*/

static pthread_mutex_t lastFreepage_mutex;
static unsigned int lastFreepage = 0;

int bufInit() {

	pageInit();
	openPageFile();
	pageCacheInit();
	openBlobStore();

	lastFreepage = 0;
	pthread_mutex_init(&lastFreepage_mutex , NULL);
	return 0;
}

void bufDeinit() {

	closeBlobStore();
	pageCacheDeinit();
	closePageFile();

	return;
}
/**
    Just close file descriptors, don't do any other clean up. (For
    testing.)
*/
void simulateBufferManagerCrash() {
  closeBlobStore();
  closePageFile();
}

/* ** No file I/O below this line. ** */

void releasePage (Page * p) {
  unlock(p->loadlatch);
}

Page * lastRallocPage = 0;

/** @todo ralloc ignores it's xid parameter; change the interface? */
recordid ralloc(int xid, /*lsn_t lsn,*/ long size) {
  
  recordid ret;
  Page * p;
  
  /*  DEBUG("Rallocing record of size %ld\n", (long int)size); */
  
  assert(size < BLOB_THRESHOLD_SIZE || size == BLOB_SLOT);
  

  pthread_mutex_lock(&lastFreepage_mutex);  
  while(freespace(p = loadPage(lastFreepage)) < size ) { 
    releasePage(p);
    lastFreepage++; 
  }
  
  ret = pageRalloc(p, size);
    
  releasePage(p);

  pthread_mutex_unlock(&lastFreepage_mutex);
  
  /*  DEBUG("alloced rid = {%d, %d, %ld}\n", ret.page, ret.slot, ret.size); */

  return ret;
}

void writeRecord(int xid, Page * p, lsn_t lsn, recordid rid, const void *dat) {

  /*  Page *p; */
  
  if(rid.size > BLOB_THRESHOLD_SIZE) {
    /*    DEBUG("Writing blob.\n"); */
    writeBlob(xid, p, lsn, rid, dat);

  } else {
    /*    DEBUG("Writing record.\n"); */

    assert( (p->id == rid.page) && (p->memAddr != NULL) );	

    /** @todo This assert should be here, but the tests are broken, so it causes bogus failures. */
    /*assert(pageReadLSN(*p) <= lsn);*/
    
    pageWriteRecord(xid, p, rid, lsn, dat);

    assert( (p->id == rid.page) && (p->memAddr != NULL) );	
    
  }
}

void readRecord(int xid, Page * p, recordid rid, void *buf) {
  if(rid.size > BLOB_THRESHOLD_SIZE) {
    /*    DEBUG("Reading blob. xid = %d rid = { %d %d %ld } buf = %x\n", 
	  xid, rid.page, rid.slot, rid.size, (unsigned int)buf); */
    /* @todo should readblob take a page pointer? */
    readBlob(xid, p, rid, buf);
  } else {
    assert(rid.page == p->id); 
    /*    DEBUG("Reading record xid = %d rid = { %d %d %ld } buf = %x\n", 
	  xid, rid.page, rid.slot, rid.size, (unsigned int)buf); */
    pageReadRecord(xid, p, rid, buf);
    assert(rid.page == p->id); 
  }
}

int bufTransCommit(int xid, lsn_t lsn) {

  commitBlobs(xid);
  pageCommit(xid);

  return 0;
}

int bufTransAbort(int xid, lsn_t lsn) {

  abortBlobs(xid);  /* abortBlobs doesn't write any log entries, so it doesn't need the lsn. */
  pageAbort(xid);

  return 0;
}