*** mp/mp_sync.c.orig	Fri Dec 11 14:28:18 1998
--- mp/mp_sync.c	Sat Mar  6 09:23:04 1999
***************
*** 39,45 ****
  	DB_ENV *dbenv;
  	MPOOL *mp;
  	MPOOLFILE *mfp;
! 	int ar_cnt, nalloc, next, ret, wrote;
  
  	MP_PANIC_CHECK(dbmp);
  
--- 39,45 ----
  	DB_ENV *dbenv;
  	MPOOL *mp;
  	MPOOLFILE *mfp;
! 	int ar_cnt, nalloc, next, maxpin, ret, wrote;
  
  	MP_PANIC_CHECK(dbmp);
  
***************
*** 119,128 ****
--- 119,133 ----
  	 * finish.  Since the application may have restarted the sync, clear
  	 * any BH_WRITE flags that appear to be left over from previous calls.
  	 *
+ 	 * We don't want to pin down the entire buffer cache, otherwise we'll
+ 	 * starve threads needing new pages.  Don't pin down more than 80% of
+ 	 * the cache.
+ 	 *
  	 * Keep a count of the total number of buffers we need to write in
  	 * MPOOL->lsn_cnt, and for each file, in MPOOLFILE->lsn_count.
  	 */
  	ar_cnt = 0;
+ 	maxpin = ((mp->stat.st_page_dirty + mp->stat.st_page_clean) * 8) / 10;
  	for (bhp = SH_TAILQ_FIRST(&mp->bhq, __bh);
  	    bhp != NULL; bhp = SH_TAILQ_NEXT(bhp, q, __bh))
  		if (F_ISSET(bhp, BH_DIRTY) || bhp->ref != 0) {
***************
*** 144,154 ****
  			 * while holding a region lock, so we set the flag to
  			 * force the checkpoint to be done again, from scratch,
  			 * later.
  			 */
  			if (bhp->ref == 0) {
  				++bhp->ref;
  				bharray[ar_cnt] = bhp;
! 				if (++ar_cnt >= nalloc) {
  					F_SET(mp, MP_LSN_RETRY);
  					break;
  				}
--- 149,163 ----
  			 * while holding a region lock, so we set the flag to
  			 * force the checkpoint to be done again, from scratch,
  			 * later.
+ 			 *
+ 			 * If we've pinned down too much of the cache stop, and
+ 			 * set a flag to force the checkpoint to be tried again
+ 			 * later.
  			 */
  			if (bhp->ref == 0) {
  				++bhp->ref;
  				bharray[ar_cnt] = bhp;
! 				if (++ar_cnt >= nalloc || ar_cnt >= maxpin) {
  					F_SET(mp, MP_LSN_RETRY);
  					break;
  				}