Doc: Refer to line pointers as item identifiers.

An upcoming HEAD-only patch will standardize the terminology around
ItemIdData variables/line pointers, ending the practice of referring to
them as "item pointers".  Make the "Database Page Layout" docs
consistent with the new policy.  The term "item identifier" is already
used in the same section, so stick with that.

Discussion: https://postgr.es/m/CAH2-Wz=c=MZQjUzde3o9+2PLAPuHTpVZPPdYxN=E4ndQ2--8ew@mail.gmail.com
Backpatch: All supported branches.

diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 164d08ce49073d7930a11c2595ef6383332b9838..adf9343363a6713c1c0d9bf1c6a8b4a5895df3f7 100644 (file)
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -730,14 +730,14 @@ free space pointers.</entry>
 
 <row>
 <entry>ItemIdData</entry>
-<entry>Array of (offset,length) pairs pointing to the actual items.
-4 bytes per item.</entry>
+<entry>Array of item identifiers pointing to the actual items. Each
+entry is an (offset,length) pair. 4 bytes per item.</entry>
 </row>
 
 <row>
 <entry>Free space</entry>
-<entry>The unallocated space. New item pointers are allocated from the start
-of this area, new items from the end.</entry>
+<entry>The unallocated space. New item identifiers are allocated from
+the start of this area, new items from the end.</entry>
 </row>
 
 <row>