Adam Dear <adear@xxxxxxxx> writes: > pg_dump: query to obtain list of schemas failed: ERROR: more than one > row returned by a subquery used as an expression > The pg_dump command is from version 7.4.11. This is the version of > postgres I am running on my old server. Just FYI, when doing a version upgrade it's considered better practice to dump with the newer version's pg_dump, if possible. Sometimes the newer pg_dump knows things that will smooth the migration. However, that's not related to your immediate problem. A look at the pg_dump source code shows that the subquery it's complaining about is trying to fetch the name of each view's owner. Apparently you've got multiple rows in pg_shadow with the same usesysid --- or perhaps just one row but the index on usesysid is corrupt and is returning it more than once. Try select ctid, usename, usesysid from pg_shadow; and see if you see any duplicate usesysid's. If so, try removing the extra copies (use WHERE ctid = '...' if there isn't any other difference between the rows). If you see no dups in a query like this, then the index is at fault --- try reindexing. regards, tom lane
