diff --git a/libsrc/Makefile.am b/libsrc/Makefile.am
index 4e3ea3dce..b6ae1c30d 100644
--- a/libsrc/Makefile.am
+++ b/libsrc/Makefile.am
@@ -34,7 +34,7 @@ netcdf.3: $(top_srcdir)/man4/netcdf.m4
 libnetcdf3_la_SOURCES = nc.h error3.c libvers.c string.c v1hpg.c fbits.h ncio.h	\
 onstack.h rnd.h utf8proc.c utf8proc.h utf8proc_data.h nclistmgr.c	\
 putget.m4 attr.m4 nc3dispatch.c nc3dispatch.h nc.c var.c dim.c ncx.m4	\
-ncx.h
+ncx.h lookup3.c
 
 # Does the user want to use ffio or posixio?
 if USE_FFIO
diff --git a/libsrc/dim.c b/libsrc/dim.c
index 6c264d28f..c9573c0cc 100644
--- a/libsrc/dim.c
+++ b/libsrc/dim.c
@@ -37,6 +37,7 @@ new_x_NC_dim(NC_string *name)
 		return NULL;
 
 	dimp->name = name;
+ 	dimp->hash = hash_fast(name->cp, strlen(name->cp));
 	dimp->size = 0;
 
 	return(dimp);
@@ -126,7 +127,7 @@ NC_finddim(const NC_dimarray *ncap, const char *uname, NC_dim **dimpp)
 {
 
    int dimid;
-   size_t slen;
+   uint32_t shash;
    NC_dim ** loc;
    char *name;
 
@@ -142,11 +143,11 @@ NC_finddim(const NC_dimarray *ncap, const char *uname, NC_dim **dimpp)
       name = (char *)utf8proc_NFC((const unsigned char *)uname);
       if(name == NULL)
 	 return NC_ENOMEM;
-      slen = strlen(name);
+      shash = hash_fast(name, strlen(name));
 
       for(; (size_t) dimid < ncap->nelems
-	     && (strlen((*loc)->name->cp) != slen
-		 || strncmp((*loc)->name->cp, name, slen) != 0);
+	     && ((*loc)->hash != shash
+		 || strncmp((*loc)->name->cp, name, strlen(name)) != 0);
 	  dimid++, loc++)
       {
 	 /*EMPTY*/
@@ -469,6 +470,7 @@ NC3_rename_dim( int ncid, int dimid, const char *unewname)
 		if(newStr == NULL)
 			return NC_ENOMEM;
 		dimp->name = newStr;
+		dimp->hash = hash_fast(newStr->cp, strlen(newStr->cp));
 		free_NC_string(old);
 		return NC_NOERR;
 	}
diff --git a/libsrc/nc.h b/libsrc/nc.h
index c6a9b6a4d..2161d4d14 100644
--- a/libsrc/nc.h
+++ b/libsrc/nc.h
@@ -11,6 +11,11 @@
  */
 #include <config.h>
 #include <stddef.h>	/* size_t */
+#ifndef HAVE_STDINT_H
+#  include "pstdint.h"	/* attempts to define uint32_t etc portably */
+#else
+#  include <stdint.h>
+#endif /* HAVE_STDINT_H */
 #include <sys/types.h>	/* off_t */
 #ifdef USE_PARALLEL
 #include <netcdf_par.h>
@@ -80,6 +85,7 @@ set_NC_string(NC_string *ncstrp, const char *str);
 typedef struct {
 	/* all xdr'd */
 	NC_string *name;
+ 	uint32_t hash;
 	size_t size;
 } NC_dim;
 
@@ -178,6 +184,7 @@ typedef struct NC_var {
 	off_t *dsizes; /* compiled info: the right to left product of shape */
 	/* below gets xdr'd */
 	NC_string *name;
+ 	uint32_t hash;
 	/* next two: formerly NC_iarray *assoc */ /* user definition */
 	size_t ndims;	/* assoc->count */
 	int *dimids;	/* assoc->value */
@@ -195,6 +202,13 @@ typedef struct NC_vararray {
 	NC_var **value;
 } NC_vararray;
 
+/* Begin defined in lookup3.c */
+
+extern uint32_t
+hash_fast(const void *key, size_t length);
+
+/* End defined in lookup3.c */
+
 /* Begin defined in var.c */
 
 extern void
diff --git a/libsrc/var.c b/libsrc/var.c
index bc1fafb63..8bcbb8b9b 100644
--- a/libsrc/var.c
+++ b/libsrc/var.c
@@ -65,6 +65,7 @@ new_x_NC_var(
 	(void) memset(varp, 0, sz);
 	varp->name = strp;
 	varp->ndims = ndims;
+ 	varp->hash = hash_fast(strp->cp, strlen(strp->cp));
 
 	if(ndims != 0)
 	{
@@ -321,7 +322,7 @@ int
 NC_findvar(const NC_vararray *ncap, const char *uname, NC_var **varpp)
 {
 	NC_var **loc;
-	size_t slen;
+ 	uint32_t shash;
 	int varid;
 	char *name;
 
@@ -336,12 +337,12 @@ NC_findvar(const NC_vararray *ncap, const char *uname, NC_var **varpp)
 	name = (char *)utf8proc_NFC((const unsigned char *)uname);
 	if(name == NULL)
 	    return NC_ENOMEM;
-	slen = strlen(name);
+ 	shash = hash_fast(name, strlen(name));
 
 	for(varid = 0; (size_t) varid < ncap->nelems; varid++, loc++)
 	{
-		if(strlen((*loc)->name->cp) == slen &&
-			strncmp((*loc)->name->cp, name, slen) == 0)
+		if((*loc)->hash == shash &&
+		   strncmp((*loc)->name->cp, name, strlen(name)) == 0)
 		{
 			if(varpp != NULL)
 				*varpp = *loc;
@@ -714,12 +715,14 @@ NC3_rename_var(int ncid, int varid, const char *unewname)
 		if(newStr == NULL)
 			return(-1);
 		varp->name = newStr;
+		varp->hash = hash_fast(newStr->cp, strlen(newStr->cp));
 		free_NC_string(old);
 		return NC_NOERR;
 	}
 
 	/* else, not in define mode */
 	status = set_NC_string(varp->name, newname);
+	varp->hash = hash_fast(newname, strlen(newname));
 	free(newname);
 	if(status != NC_NOERR)
 		return status;