Upgrading to v12

I'm upgrading from v9.4 to v12.10 as a half step to 15.

Q1: How do I tell it which database to upgrade?
I only need the primary.
Not the half dozen restored copies.
Or do I need to detach everything I don't want copied?

Q2: I get this error, and then at the end, it says "No error."

Performing Consistency Checks
-----------------------------
Checking cluster versions ok
SQL command failed
WITH regular_heap (reloid, indtable, toastheap) AS ( SELECT c.oid,
0::oid, 0::oid FROM pg_catalog.pg_class c JOIN pg_catalog.pg_namespace n
ON c.relnamespace = n.oid WHERE relkind IN ('r', 'm') AND
((n.nspname !~ '^pg_temp_' AND n.nspname !~ '^pg_toast_temp_' AND
n.nspname NOT IN ('pg_catalog', 'information_schema',
'binary_upgrade', 'pg_toast') AND c.oid >= 16384::pg_catalog.oid)
OR (n.nspname = 'pg_catalog' AND relname IN ('pg_largeobject')
))), toast_heap (reloid, indtable, toastheap) AS ( SELECT
c.reltoastrelid, 0::oid, c.oid FROM regular_heap JOIN pg_catalog.pg_class
c ON regular_heap.reloid = c.oid WHERE c.reltoastrelid != 0),
all_index (reloid, indtable, toastheap) AS ( SELECT indexrelid, indrelid,
0::oid FROM pg_catalog.pg_index WHERE indisvalid AND indisready AND
indrelid IN (SELECT reloid FROM regular_heap UNION ALL
SELECT reloid FROM toast_heap)) SELECT all_rels.*, n.nspname,
c.relname, c.relfilenode, c.reltablespace,
pg_catalog.pg_tablespace_location(t.oid) AS spclocation FROM (SELECT * FROM
regular_heap UNION ALL SELECT * FROM toast_heap UNION ALL
SELECT * FROM all_index) all_rels JOIN pg_catalog.pg_class c
ON all_rels.reloid = c.oid JOIN pg_catalog.pg_namespace n ON
c.relnamespace = n.oid LEFT OUTER JOIN pg_catalog.pg_tablespace t ON
c.reltablespace = t.oid ORDER BY 1;
ERROR: could not access status of transaction 22316920
DETAIL: Could not read from file "pg_clog/0015" at offset 73728: No error.