From 5cfa05ee9c6f075875b4eb9ad6d64e81c9cbdcbb Mon Sep 17 00:00:00 2001
From: "Paul A. Jungwirth" <pj@illuminatedcomputing.com>
Date: Tue, 20 Jan 2026 10:33:31 -0800
Subject: [PATCH v1] docs: Clarify cmin and cmax system columns

These are two names for the same physical field. The docs suggested that they
were distinct, and the cmax description was simply wrong for not-yet-deleted
rows.
---
 doc/src/sgml/ddl.sgml | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 9070aaa5a7c..7fdfc8da1b8 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -1510,7 +1510,10 @@ CREATE TABLE circles (
 
      <para>
       The command identifier (starting at zero) within the inserting
-      transaction.
+      transaction.  Once the row has been deleted, this is replaced by the
+      identifier of the delete command (or a combo identifier, if still in the
+      same transaction as the insert). <structfield>cmin</structfield> always
+      has the same value as <structfield>cmax</structfield>.
      </para>
     </listitem>
    </varlistentry>
@@ -1540,7 +1543,12 @@ CREATE TABLE circles (
      </indexterm>
 
      <para>
-      The command identifier within the deleting transaction, or zero.
+      The command identifier (starting at zero) within the deleting
+      transaction.  If the row has not yet been deleted, this is the identifier
+      of the insert command. If the row was inserted and deleted in the same
+      transaction, it is a combo identifier instead, whose meaning is private
+      to that transaction. <structfield>cmax</structfield> always has the same
+      value as <structfield>cmin</structfield>.
      </para>
     </listitem>
    </varlistentry>
-- 
2.47.3