Horton

Re: preserving db/ts/relfilenode OIDs across pg_upgrade (was Re: storing an explicit nonce)

Shruthi Gowda <gowdashru@gmail.com>

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From: Shruthi Gowda <gowdashru@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Sadhuprasad Patro <b.sadhu@gmail.com>, Stephen Frost <sfrost@snowman.net>, Bruce Momjian <bruce@momjian.us>, Andres Freund <andres@anarazel.de>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Masahiko Sawada <sawada.mshk@gmail.com>, Tom Kincaid <tomjohnkincaid@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, PostgreSQL Development <pgsql-hackers@postgresql.org>, Masahiko Sawada <masahiko.sawada@2ndquadrant.com>, Tom Lane <tgl@sss.pgh.pa.us>
Date: 2021-12-13T15:13:32Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Rethink method for assigning OIDs to the template0 and postgres DBs.

  2. pg_upgrade: Preserve database OIDs.

  3. pg_upgrade: Preserve relfilenodes and tablespace OIDs.

  4. Fix for new Boolean node

  5. Improve error handling of HMAC computations

  6. Add macro RelationIsPermanent() to report relation permanence

  7. Enhance nbtree index tuple deletion.

On Mon, Dec 6, 2021 at 11:25 PM Robert Haas <robertmhaas@gmail.com> wrote:
>
> On Sun, Dec 5, 2021 at 11:44 PM Sadhuprasad Patro <b.sadhu@gmail.com> wrote:
> > 3.
> > @@ -504,11 +525,15 @@ createdb(ParseState *pstate, const CreatedbStmt *stmt)
> >   */
> >   pg_database_rel = table_open(DatabaseRelationId, RowExclusiveLock);
> >
> > - do
> > + /* Select an OID for the new database if is not explicitly configured. */
> > + if (!OidIsValid(dboid))
> >   {
> > - dboid = GetNewOidWithIndex(pg_database_rel, DatabaseOidIndexId,
> > -    Anum_pg_database_oid);
> > - } while (check_db_file_conflict(dboid));
> >
> > I think we need to do 'check_db_file_conflict' for the USER given OID
> > also.. right? It may already be present.
>
> Hopefully, if that happens, we straight up fail later on.

That's right. If a database with user-specified OID exists, the
createdb fails with a "duplicate key value" error.
If just a data directory with user-specified OID exists,
MakePGDirectory() fails to create the directory and the cleanup
callback createdb_failure_callback() removes the directory that was
not created by 'createdb()' function.
The subsequent create database call with the same OID will succeed.
Should we handle the case where a data directory exists and the
corresponding DB with that oid does not exist? I presume this
situation doesn't arise unless the user tries to create directories in
the data path. Any thoughts?


Thanks & Regards
Shruthi KC
EnterpriseDB: http://www.enterprisedb.com