Fix position seek bug for varchar short key (#1167)

apache · May 16, 2019 · 18e06d2 · 18e06d2
1 parent b2e6391
commit 18e06d2
Showing 1 changed file with 14 additions and 1 deletion.
diff --git a/be/src/olap/field.h b/be/src/olap/field.h
@@ -154,11 +154,24 @@ inline int Field::index_cmp(char* left, char* right) const {
         Slice* l_slice = reinterpret_cast<Slice*>(left + 1);
         Slice* r_slice = reinterpret_cast<Slice*>(right + 1);
 
-        if (r_slice->size + OLAP_STRING_MAX_BYTES > _index_size) {
+        if (r_slice->size + OLAP_STRING_MAX_BYTES > _index_size
+                || l_slice->size + OLAP_STRING_MAX_BYTES > _index_size) {
             // 如果field的实际长度比short key长，则仅比较前缀，确保相同short key的所有block都被扫描，
             // 否则，可以直接比较short key和field
             int compare_size = _index_size - OLAP_STRING_MAX_BYTES;
+            // l_slice size and r_slice size may be less than compare_size
+            // so calculate the min of the three size as new compare_size
+            compare_size = std::min(std::min(compare_size, (int)l_slice->size), (int)r_slice->size);
             res = strncmp(l_slice->data, r_slice->data, compare_size);
+            if (res == 0) {
+                if (l_slice->size < r_slice->size) {
+                    res = -1;
+                } else if (l_slice->size > r_slice->size) {
+                    res = 1;
+                } else {
+                    res = 0;
+                }
+            }
         } else {
             res = l_slice->compare(*r_slice);
         }