diff --git a/src/backend/access/gin/ginfast.c b/src/backend/access/gin/ginfast.c
index 4a65046..38cda14 100644
*** a/src/backend/access/gin/ginfast.c
--- b/src/backend/access/gin/ginfast.c
***************
*** 21,26 ****
--- 21,27 ----
  #include "access/gin_private.h"
  #include "commands/vacuum.h"
  #include "miscadmin.h"
+ #include "storage/lmgr.h"
  #include "utils/memutils.h"
  #include "utils/rel.h"
  
*************** ginInsertCleanup(GinState *ginstate,
*** 739,744 ****
--- 740,755 ----
  	KeyArray	datums;
  	BlockNumber blkno;
  
+ 	/*
+ 	 * We use a heavyweight lock on the metapage to ensure that only one
+ 	 * backend at a time tries to clean up the pending list.  While it does
+ 	 * actually work for multiple backends to run this code concurrently, that
+ 	 * turns out to be a bad idea because there's lots of locking conflicts.
+ 	 * So if someone else is already running cleanup, we just do nothing.
+ 	 */
+ 	if (!ConditionalLockPage(index, GIN_METAPAGE_BLKNO, ExclusiveLock))
+ 		return;
+ 
  	metabuffer = ReadBuffer(index, GIN_METAPAGE_BLKNO);
  	LockBuffer(metabuffer, GIN_SHARE);
  	metapage = BufferGetPage(metabuffer);
*************** ginInsertCleanup(GinState *ginstate,
*** 748,753 ****
--- 759,765 ----
  	{
  		/* Nothing to do */
  		UnlockReleaseBuffer(metabuffer);
+ 		UnlockPage(index, GIN_METAPAGE_BLKNO, ExclusiveLock);
  		return;
  	}
  
*************** ginInsertCleanup(GinState *ginstate,
*** 925,930 ****
--- 937,944 ----
  
  	ReleaseBuffer(metabuffer);
  
+ 	UnlockPage(index, GIN_METAPAGE_BLKNO, ExclusiveLock);
+ 
  	/* Clean up temporary space */
  	MemoryContextSwitchTo(oldCtx);
  	MemoryContextDelete(opCtx);