On Thu, Dec 14, 2017 at 08:51:06AM +0700, Ali Akbar wrote:
> Patch for adding check in pg_upgrade.
[...]
On Fri, Sep 29, 2023 at 11:36:42AM -0500, Justin Pryzby wrote:
> On Fri, Sep 29, 2023 at 09:16:35AM +0900, Michael Paquier wrote:
> > You mean when upgrading from an instance of 9.6 or older as c30f177 is
> > not there, right?
>
> No - while upgrading from v15 to v16. I'm not clear on how we upgraded
> *to* v15 without hitting the issue, nor how the "not null" got
> dropped...
>
> > Anyway, it seems like the patch from [1] has no need to run this check
> > when the old cluster's version is 10 or newer. And perhaps it should
> > mention that this check could be removed from pg_upgrade once v10
> > support is out of scope, in the shape of a comment.
>
> You're still thinking of PRIMARY KEY as the only way to hit this, right?
> But Ali Akbar already pointed out how to reproduce the problem with DROP
> NOT NULL - which still applies to both v16 and v17.
Rebased and amended the forgotten patch.
See also ZiE3NoY6DdvlvFl9@pryzbyj2023 et seq.
>From f804bec39acac0b53e29563be9ef7a10237ba717 Mon Sep 17 00:00:00 2001
From: Ali Akbar <the.ap...@gmail.com>
Date: Thu, 14 Dec 2017 19:18:59 +0700
Subject: [PATCH] pg_upgrade: check for inconsistent inherited not null columns
Otherwise, the upgrade can fail halfway through with error:
CREATE TABLE ip(id int PRIMARY KEY); CREATE TABLE ic(id int) INHERITS (ip); ALTER TABLE ic ALTER id DROP NOT NULL;
ERROR: column "a" in child table must be marked NOT NULL
JTP: updated to handle contype='n' - otherwise, the cnn_grandchild2
added at b0e96f311 triggers the issue this patch tries to avoid ...
Should be backpatched to all versions.
---
src/bin/pg_upgrade/check.c | 101 +++++++++++++++++++++++++++++++++++++
1 file changed, 101 insertions(+)
diff --git a/src/bin/pg_upgrade/check.c b/src/bin/pg_upgrade/check.c
index ad1f8e3bcb1..79671a9cdb4 100644
--- a/src/bin/pg_upgrade/check.c
+++ b/src/bin/pg_upgrade/check.c
@@ -31,6 +31,7 @@ static void check_new_cluster_logical_replication_slots(void);
static void check_new_cluster_subscription_configuration(void);
static void check_old_cluster_for_valid_slots(bool live_check);
static void check_old_cluster_subscription_state(void);
+static void check_for_not_null_inheritance(ClusterInfo *cluster);
/*
* DataTypesUsageChecks - definitions of data type checks for the old cluster
@@ -646,6 +647,8 @@ check_and_dump_old_cluster(bool live_check)
if (GET_MAJOR_VERSION(old_cluster.major_version) <= 1100)
check_for_tables_with_oids(&old_cluster);
+ check_for_not_null_inheritance(&old_cluster);
+
/*
* Pre-PG 10 allowed tables with 'unknown' type columns and non WAL logged
* hash indexes
@@ -1832,6 +1835,104 @@ check_new_cluster_subscription_configuration(void)
check_ok();
}
+/*
+ * check_for_not_null_inheritance()
+ *
+ * Currently pg_upgrade will fail if there are any inconsistencies in NOT NULL
+ * constraint inheritance: In PostgreSQL, we can have a column that is NOT NULL
+ * in parent, but nullable in its children. So check for inconsistent NOT NULL
+ * constraints in inheritance tree.
+ */
+static void
+check_for_not_null_inheritance(ClusterInfo *cluster)
+{
+ int dbnum;
+ FILE *script = NULL;
+ char output_path[MAXPGPATH];
+
+ prep_status("Checking for NOT NULL inconsistencies in inheritance");
+
+ snprintf(output_path, sizeof(output_path), "not_null_inconsistent_columns.txt");
+
+ for (dbnum = 0; dbnum < cluster->dbarr.ndbs; dbnum++)
+ {
+ PGresult *res;
+ bool db_used = false;
+ int ntups;
+ int rowno;
+ int i_nspname,
+ i_relname,
+ i_attname;
+ DbInfo *active_db = &cluster->dbarr.dbs[dbnum];
+ PGconn *conn = connectToServer(cluster, active_db->db_name);
+
+ res = executeQueryOrDie(conn,
+ "WITH RECURSIVE parents AS ( "
+ " SELECT i.inhrelid, i.inhparent "
+ " FROM pg_catalog.pg_inherits i "
+ " UNION ALL "
+ " SELECT p.inhrelid, i.inhparent "
+ " FROM parents p "
+ " JOIN pg_catalog.pg_inherits i "
+ " ON i.inhrelid = p.inhparent "
+ ") "
+ "SELECT n.nspname, c.relname, ac.attname "
+ "FROM parents p, "
+ " pg_catalog.pg_attribute ac, "
+ " pg_catalog.pg_attribute ap, "
+ " pg_catalog.pg_constraint cc, "
+ " pg_catalog.pg_class c, "
+ " pg_catalog.pg_namespace n "
+ "WHERE NOT ac.attnotnull AND "
+ " ac.attrelid = p.inhrelid AND "
+ " ap.attrelid = p.inhparent AND "
+ " ac.attname = ap.attname AND "
+ " ac.attrelid = cc.conrelid AND ac.attnum = ANY(cc.conkey) AND contype='n' AND NOT connoinherit AND"
+ " ap.attnotnull AND "
+ " c.oid = ac.attrelid AND "
+ " c.relnamespace = n.oid");
+
+ ntups = PQntuples(res);
+ i_nspname = PQfnumber(res, "nspname");
+ i_relname = PQfnumber(res, "relname");
+ i_attname = PQfnumber(res, "attname");
+ for (rowno = 0; rowno < ntups; rowno++)
+ {
+ if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
+ pg_fatal("could not open file \"%s\": %s", output_path,
+ strerror(errno));
+ if (!db_used)
+ {
+ fprintf(script, "Database: %s\n", active_db->db_name);
+ db_used = true;
+ }
+ fprintf(script, " %s.%s.%s\n",
+ PQgetvalue(res, rowno, i_nspname),
+ PQgetvalue(res, rowno, i_relname),
+ PQgetvalue(res, rowno, i_attname));
+ }
+
+ PQclear(res);
+
+ PQfinish(conn);
+ }
+
+ if (script)
+ {
+ fclose(script);
+ pg_log(PG_REPORT, "fatal");
+ pg_fatal("Your installation contains has inconsistencies in NOT NULL\n"
+ "constraint inheritance: child column is not marked NOT NULL\n"
+ "while parent column has NOT NULL constraint. You can fix the\n"
+ "inconsistency by adding NOT NULL constraints and rerunning the\n"
+ "upgrade.\n"
+ "A list of the problematic columns is in the file:\n"
+ " %s", output_path);
+ }
+ else
+ check_ok();
+}
+
/*
* check_old_cluster_for_valid_slots()
*
--
2.42.0
