@@ -1163,10 +1163,10 @@ CREATE INDEX test1c_content_y_index ON test1c (content COLLATE "y");
11631163 </indexterm>
11641164
11651165 <para>
1166- All indexes in <productname>PostgreSQL </> are <firstterm>secondary</>
1166+ All indexes in <productname>&productname; </> are <firstterm>secondary</>
11671167 indexes, meaning that each index is stored separately from the table's
11681168 main data area (which is called the table's <firstterm>heap</>
1169- in <productname>PostgreSQL </> terminology). This means that in an
1169+ in <productname>&productname; </> terminology). This means that in an
11701170 ordinary index scan, each row retrieval requires fetching data from both
11711171 the index and the heap. Furthermore, while the index entries that match a
11721172 given indexable <literal>WHERE</> condition are usually close together in
@@ -1179,7 +1179,7 @@ CREATE INDEX test1c_content_y_index ON test1c (content COLLATE "y");
11791179 </para>
11801180
11811181 <para>
1182- To solve this performance problem, <productname>PostgreSQL </>
1182+ To solve this performance problem, <productname>&productname; </>
11831183 supports <firstterm>index-only scans</>, which can answer queries from an
11841184 index alone without any heap access. The basic idea is to return values
11851185 directly out of each index entry instead of consulting the associated heap
@@ -1226,14 +1226,14 @@ SELECT x FROM tab WHERE x = 'key' AND z < 42;
12261226 If these two fundamental requirements are met, then all the data values
12271227 required by the query are available from the index, so an index-only scan
12281228 is physically possible. But there is an additional requirement for any
1229- table scan in <productname>PostgreSQL </>: it must verify that each
1229+ table scan in <productname>&productname; </>: it must verify that each
12301230 retrieved row be <quote>visible</> to the query's MVCC snapshot, as
12311231 discussed in <xref linkend="mvcc">. Visibility information is not stored
12321232 in index entries, only in heap entries; so at first glance it would seem
12331233 that every row retrieval would require a heap access anyway. And this is
12341234 indeed the case, if the table row has been modified recently. However,
12351235 for seldom-changing data there is a way around this
1236- problem. <productname>PostgreSQL </> tracks, for each page in a table's
1236+ problem. <productname>&productname; </> tracks, for each page in a table's
12371237 heap, whether all rows stored in that page are old enough to be visible to
12381238 all current and future transactions. This information is stored in a bit
12391239 in the table's <firstterm>visibility map</>. An index-only scan, after
@@ -1284,7 +1284,7 @@ SELECT y FROM tab WHERE x = 'key';
12841284SELECT f(x) FROM tab WHERE f(x) < 1;
12851285</programlisting>
12861286 as an index-only scan; and this is very attractive if <literal>f()</> is
1287- an expensive-to-compute function. However, <productname>PostgreSQL </>'s
1287+ an expensive-to-compute function. However, <productname>&productname; </>'s
12881288 planner is currently not very smart about such cases. It considers a
12891289 query to be potentially executable by index-only scan only when
12901290 all <emphasis>columns</> needed by the query are available from the index.
@@ -1300,7 +1300,7 @@ SELECT f(x) FROM tab WHERE f(x) < 1;
13001300 indexable <literal>WHERE</> clauses to the index column. It will usually
13011301 get this right in simple queries such as shown above, but not in queries
13021302 that involve joins. These deficiencies may be remedied in future versions
1303- of <productname>PostgreSQL </>.
1303+ of <productname>&productname; </>.
13041304 </para>
13051305
13061306 <para>
@@ -1321,7 +1321,7 @@ SELECT target FROM tests WHERE subject = 'some-subject' AND success;
13211321 not need to recheck that part of the <literal>WHERE</> clause at run time:
13221322 all entries found in the index necessarily have <literal>success = true</>
13231323 so this need not be explicitly checked in the
1324- plan. <productname>PostgreSQL </> versions 9.6 and later will recognize
1324+ plan. <productname>&productname; </> versions 9.6 and later will recognize
13251325 such cases and allow index-only scans to be generated, but older versions
13261326 will not.
13271327 </para>