--- a/src/INSTALL
+++ b/src/INSTALL
@@ -631,8 +631,9 @@
Threshold (megabytes of new text data) where we flush from memory
to disk index. Setting this can help control memory usage. A value
of 0 means no explicit flushing, letting Xapian use its own
- default, which is flushing every 10000 documents (memory usage
- depends on average document size). The default value is 10.
+ default, which is flushing every 10000 (or XAPIAN_FLUSH_THRESHOLD)
+ documents, which gives little memory usage control, as memory
+ usage depends on average document size. The default value is 10.
5.4.1.4. Miscellaneous parameters: