Re: Use "WAL segment" instead of "log segment" consistently in user-facing messages

    At all times, <productname>PostgreSQL</productname> maintains a
    <firstterm>write ahead log</firstterm> (WAL) in the <filename>pg_wal/</filename>
-   subdirectory of the cluster's data directory. The log records
-   every change made to the database's data files.  This log exists
+   subdirectory of the cluster's data directory. The WAL records
+   capture every change made to the database's data files.  This log exists

I don't think this change really adds anything.  The preceding sentence
makes it clear that we are discussing the write-ahead log, and IMO the
change in phrasing ("the log records every change" is changed to "the
records capture every change") subtly changes the meaning of the sentence.

The rest looks good to me. 

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com