dict0dict.h, dict0dict.c, row0row.c, pars0opt.c:

  Fix bug #5180: having a column prefix index in the primary key, and the same column fully in a secondary key could cause an assertion failure in row_build_row_ref()

innobase/dict/dict0dict.c

@@ -526,8 +526,10 @@ dict_index_contains_col_or_prefix(
 }
 
 /************************************************************************
-Looks for a matching field in an index. The column and the prefix len have
-to be the same. */
+Looks for a matching field in an index. The column has to be the same. The
+column in index must be complete, or must contain a prefix longer than the
+column in index2. That is, we must be able to construct the prefix in index2
+from the prefix in index. */
 
 ulint
 dict_index_get_nth_field_pos(
@@ -555,7 +557,9 @@ dict_index_get_nth_field_pos(
 		field = dict_index_get_nth_field(index, pos);
 
 		if (field->col == field2->col
-		    && field->prefix_len == field2->prefix_len) {
+		    && (field->prefix_len == 0
+			|| (field->prefix_len >= field2->prefix_len
+			    && field2->prefix_len != 0))) {
 
 			return(pos);
 		}

innobase/include/dict0dict.h

@@ -566,8 +566,10 @@ dict_index_contains_col_or_prefix(
 	dict_index_t*	index,	/* in: index */
 	ulint		n);	/* in: column number */
 /************************************************************************
-Looks for a matching field in an index. The column and the prefix len has
-to be the same. */
+Looks for a matching field in an index. The column has to be the same. The
+column in index must be complete, or must contain a prefix longer than the
+column in index2. That is, we must be able to construct the prefix in index2
+from the prefix in index. */
 
 ulint
 dict_index_get_nth_field_pos(

innobase/pars/pars0opt.c

@@ -1094,6 +1094,19 @@ opt_clust_access(
 	for (i = 0; i < n_fields; i++) {
 		pos = dict_index_get_nth_field_pos(index, clust_index, i);
 
+		ut_a(pos != ULINT_UNDEFINED);
+
+		/* We optimize here only queries to InnoDB's internal system
+		tables, and they should not contain column prefix indexes. */
+
+		if (dict_index_get_nth_field(index, pos)->prefix_len != 0
+		    || dict_index_get_nth_field(clust_index, i)
+							->prefix_len != 0) {
+			fprintf(stderr,
+"InnoDB: Error in pars0opt.c: table %s has prefix_len != 0\n",
+				index->table_name);
+		}
+
 		*(plan->clust_map + i) = pos;
 
 		ut_ad((pos != ULINT_UNDEFINED)

innobase/row/row0row.c

@@ -334,6 +334,7 @@ row_build_row_ref(
 	ulint		ref_len;
 	ulint		pos;
 	byte*		buf;
+	ulint		clust_col_prefix_len;
 	ulint		i;
 	
 	ut_ad(index && rec && heap);
@@ -366,6 +367,22 @@ row_build_row_ref(
 		field = rec_get_nth_field(rec, pos, &len);
 
 		dfield_set_data(dfield, field, len);
+
+		/* If the primary key contains a column prefix, then the
+		secondary index may contain a longer prefix of the same
+		column, or the full column, and we must adjust the length
+		accordingly. */
+
+		clust_col_prefix_len =
+			dict_index_get_nth_field(clust_index, i)->prefix_len;
+
+		if (clust_col_prefix_len > 0) {
+		    	if (len != UNIV_SQL_NULL
+			    && len > clust_col_prefix_len) {
+
+				dfield_set_len(dfield, clust_col_prefix_len);
+			}
+		}
 	}
 
 	ut_ad(dtuple_check_typed(ref));
@@ -396,6 +413,7 @@ row_build_row_ref_in_tuple(
 	ulint		len;
 	ulint		ref_len;
 	ulint		pos;
+	ulint		clust_col_prefix_len;
 	ulint		i;
 	
 	ut_a(ref && index && rec);
@@ -433,6 +451,22 @@ row_build_row_ref_in_tuple(
 		field = rec_get_nth_field(rec, pos, &len);
 
 		dfield_set_data(dfield, field, len);
+
+		/* If the primary key contains a column prefix, then the
+		secondary index may contain a longer prefix of the same
+		column, or the full column, and we must adjust the length
+		accordingly. */
+
+		clust_col_prefix_len =
+			dict_index_get_nth_field(clust_index, i)->prefix_len;
+
+		if (clust_col_prefix_len > 0) {
+		    	if (len != UNIV_SQL_NULL
+			    && len > clust_col_prefix_len) {
+
+				dfield_set_len(dfield, clust_col_prefix_len);
+			}
+		}
 	}
 
 	ut_ad(dtuple_check_typed(ref));