[#2957] Fix dhcp4_server_modification_ts index

src/share/database/scripts/pgsql/upgrade_020_to_021.sh.in
    - new file, corrects dhcp4_server_modifcation_ts index

configure.ac
    added src/share/database/scripts/pgsql/upgrade_020_to_021.sh

src/bin/admin/tests/pgsql_tests.sh.in
    Added pgsql_upgrade_20_to_21_test()

src/lib/pgsql/pgsql_connection.h
    Updated schema version

src/share/database/scripts/pgsql/.gitignore
src/share/database/scripts/pgsql/Makefile.am
    Added upgrade_020_to_021.sh

src/share/database/scripts/pgsql/dhcpdb_create.pgsql
    Added correction of dhcp4_server_modifcation_ts index

4 files changed, 69 insertions, 0 deletions

diff --git a/src/share/database/scripts/pgsql/.gitignore b/src/share/database/scripts/pgsql/.gitignore
index b4156d8989..b8e0b819f2 100644
--- a/src/share/database/scripts/pgsql/.gitignore
+++ b/src/share/database/scripts/pgsql/.gitignore
@@ -23,4 +23,5 @@
 /upgrade_017_to_018.sh
 /upgrade_018_to_019.sh
 /upgrade_019_to_020.sh
+/upgrade_020_to_021.sh
 /wipe_data.sh
diff --git a/src/share/database/scripts/pgsql/Makefile.am b/src/share/database/scripts/pgsql/Makefile.am
index 32685c44e5..a7049a4c96 100644
--- a/src/share/database/scripts/pgsql/Makefile.am
+++ b/src/share/database/scripts/pgsql/Makefile.am
@@ -34,6 +34,7 @@ pgsql_SCRIPTS += upgrade_016_to_017.sh
 pgsql_SCRIPTS += upgrade_017_to_018.sh
 pgsql_SCRIPTS += upgrade_018_to_019.sh
 pgsql_SCRIPTS += upgrade_019_to_020.sh
+pgsql_SCRIPTS += upgrade_020_to_021.sh
 pgsql_SCRIPTS += wipe_data.sh
 
 DISTCLEANFILES = ${pgsql_SCRIPTS}
diff --git a/src/share/database/scripts/pgsql/dhcpdb_create.pgsql b/src/share/database/scripts/pgsql/dhcpdb_create.pgsql
index 36502129f3..bececdcd76 100644
--- a/src/share/database/scripts/pgsql/dhcpdb_create.pgsql
+++ b/src/share/database/scripts/pgsql/dhcpdb_create.pgsql
@@ -6325,6 +6325,18 @@ UPDATE schema_version
 
 -- This line concludes the schema upgrade to version 20.0.
 
+-- This line starts the schema upgrade to version 21.0.
+
+-- Correct dhcp4_server_modifcation_ts to index the dhcp4_server table.
+DROP INDEX dhcp4_server_modification_ts;
+CREATE INDEX dhcp4_server_modification_ts ON dhcp4_server (modification_ts);
+
+-- Update the schema version number.
+UPDATE schema_version
+    SET version = '21', minor = '0';
+
+-- This line concludes the schema upgrade to version 21.0.
+
 -- Commit the script transaction.
 COMMIT;
 
diff --git a/src/share/database/scripts/pgsql/upgrade_020_to_021.sh.in b/src/share/database/scripts/pgsql/upgrade_020_to_021.sh.in
new file mode 100644
index 0000000000..65b2e0496e
--- /dev/null
+++ b/src/share/database/scripts/pgsql/upgrade_020_to_021.sh.in
@@ -0,0 +1,55 @@
+#!/bin/sh
+
+# Copyright (C) 2023-2024 Internet Systems Consortium, Inc. ("ISC")
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Exit with error if commands exit with non-zero and if undefined variables are
+# used.
+set -eu
+
+# shellcheck disable=SC2034
+# SC2034: ... appears unused. Verify use (or export if used externally).
+prefix="@prefix@"
+
+# Include utilities based on location of this script. Check for sources first,
+# so that the unexpected situations with weird paths fall on the default
+# case of installed.
+script_path=$(cd "$(dirname "${0}")" && pwd)
+if test "${script_path}" = "@abs_top_builddir@/src/share/database/scripts/pgsql"; then
+    # shellcheck source=./src/bin/admin/admin-utils.sh.in
+    . "@abs_top_builddir@/src/bin/admin/admin-utils.sh"
+else
+    # shellcheck source=./src/bin/admin/admin-utils.sh.in
+    . "@datarootdir@/@PACKAGE_NAME@/scripts/admin-utils.sh"
+fi
+
+VERSION=$(pgsql_version "$@")
+
+if [ "$VERSION" != "20.0" ]; then
+    printf 'This script upgrades 20.0 to 21.0. '
+    printf 'Reported version is %s. Skipping upgrade.\n' "${VERSION}"
+    exit 0
+fi
+
+psql "$@" >/dev/null <<EOF
+START TRANSACTION;
+
+-- This line starts the schema upgrade to version 21.0.
+
+-- Correct dhcp4_server_modifcation_ts to index the dhcp4_server table.
+DROP INDEX dhcp4_server_modification_ts;
+CREATE INDEX dhcp4_server_modification_ts ON dhcp4_server (modification_ts);
+
+-- Update the schema version number.
+UPDATE schema_version
+    SET version = '21', minor = '0';
+
+-- This line concludes the schema upgrade to version 21.0.
+
+-- Commit the script transaction.
+COMMIT;
+
+EOF