Point-in-Time Recovery for YSQL - Yugabyte Db

Point-in-time recovery (PITR) allows you to restore the state of your cluster's data and certain types of metadata from a specific point in time. This can be relative, such as "three hours ago", or an absolute timestamp.

For more information, see Point-in-time recovery. For details on the yb-admin commands, refer to the Backup and snapshot commands section of the yb-admin documentation.

The following examples show how you can use the PITR feature by creating a database and populating it, creating a snapshot schedule, and restoring from a snapshot on the schedule.

Note that the examples are deliberately simplified. In many of the scenarios, you could drop the index or table to recover. Consider the examples as part of an effort to undo a larger schema change, such as a database migration, which has performed several operations.

Set up universe

The examples run on a local multi-node YugabyteDB universe. To create a universe, see Set up YugabyteDB universe.

Undo data changes

The process of undoing data changes involves creating and taking a snapshot of a table, and then performing a restore from either an absolute or relative time.

Before attempting a restore, you need to confirm that there is no restore in progress for the subject keyspace or table; if multiple restore commands are issued, the data might enter an inconsistent state. For details, see Restore to a point in time.

Create a table

Start the YSQL shell and connect to your local instance:
sh
```
./bin/ysqlsh -h 127.0.0.1
```

Create a table and populate some sample data:

sql

CREATE TABLE employees (
  employee_no integer PRIMARY KEY,
  name text,
  department text,
  salary integer
);

INSERT INTO employees (employee_no, name, department, salary)
  VALUES
  (1221, 'John Smith', 'Marketing', 50000),
  (1222, 'Bette Davis', 'Sales', 55000),
  (1223, 'Lucille Ball', 'Operations', 70000),
  (1224, 'John Zimmerman', 'Sales', 60000);

SELECT * from employees;

output

 employee_no |      name      | department | salary
-------------+----------------+------------+--------
        1223 | Lucille Ball   | Operations |  70000
        1224 | John Zimmerman | Sales      |  60000
        1221 | John Smith     | Marketing  |  50000
        1222 | Bette Davis    | Sales      |  55000
(4 rows)

Create a snapshot

Create a snapshot as follows:

At a terminal prompt, create a snapshot schedule for the database from a shell prompt. In the following example, the schedule is one snapshot every minute, and each snapshot is retained for ten minutes:
sh
```
./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    create_snapshot_schedule 1 10 ysql.yugabyte
```
output.json
```
{
    "schedule_id": "0e4ceb83-fe3d-43da-83c3-013a8ef592ca"
}
```

Verify that a snapshot has happened:

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    list_snapshot_schedules

output.json

{
    "schedules": [
        {
            "id": "0e4ceb83-fe3d-43da-83c3-013a8ef592ca",
            "options": {
                "interval": "60.000s",
                "retention": "600.000s"
            },
            "snapshots": [
                {
                    "id": "8d588cb7-13f2-4bda-b584-e9be47a144c5",
                    "snapshot_time_utc": "2021-05-07T20:16:08.492330+0000"
                }
            ]
        }
    ]
}

Restore from an absolute time

From a command prompt, get a timestamp:

python -c 'import datetime; print(datetime.datetime.now().strftime("%s%f"))'

output

1620418817729963

Add a row for employee 9999 to the table:

sql

INSERT INTO employees (employee_no, name, department, salary)
  VALUES
  (9999, 'Wrong Name', 'Marketing', 10000);

SELECT * FROM employees;

output

 employee_no |      name      | department | salary
-------------+----------------+------------+--------
        1223 | Lucille Ball   | Operations |  70000
        9999 | Wrong Name     | Marketing  |  10000
        1224 | John Zimmerman | Sales      |  60000
        1221 | John Smith     | Marketing  |  50000
        1222 | Bette Davis    | Sales      |  55000
(5 rows)

Restore the snapshot schedule to the timestamp you obtained before you added the data, at a terminal prompt:

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    restore_snapshot_schedule 0e4ceb83-fe3d-43da-83c3-013a8ef592ca 1620418817729963

output.json

{
    "snapshot_id": "2287921b-1cf9-4bbc-ad38-e309f86f72e9",
    "restoration_id": "1c5ef7c3-a33a-46b5-a64e-3fa0c72709eb"
}

Next, verify the restoration is in RESTORED state (you'll see more snapshots in the list, as well):

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    list_snapshots

output

Snapshot UUID                           State       Creation Time
8d588cb7-13f2-4bda-b584-e9be47a144c5    COMPLETE    2023-04-20 00:24:58.246932
1f4db0e2-0706-45db-b157-e577702a648a    COMPLETE    2023-04-20 00:26:03.257519
b91c734b-5c57-4276-851e-f982bee73322    COMPLETE    2023-04-20 00:27:08.272905
04fc6f05-8775-4b43-afbd-7a11266da110    COMPLETE    2023-04-20 00:28:13.287202
e7bc7b48-351b-4713-b46b-dd3c9c028a79    COMPLETE    2023-04-20 00:29:18.294031
2287921b-1cf9-4bbc-ad38-e309f86f72e9    COMPLETE    2023-04-20 00:30:23.306355
97aa2968-6b56-40ce-b2c5-87d2e54e9786    COMPLETE    2023-04-20 00:31:28.319685
Restoration UUID                        State
1c5ef7c3-a33a-46b5-a64e-3fa0c72709eb    RESTORED

In the YSQL shell, verify the data is restored, without a row for employee 9999:

sql

yugabyte=# select * from employees;

output

 employee_no |      name      | department | salary
-------------+----------------+------------+--------
        1223 | Lucille Ball   | Operations |  70000
        1224 | John Zimmerman | Sales      |  60000
        1221 | John Smith     | Marketing  |  50000
        1222 | Bette Davis    | Sales      |  55000
(4 rows)

Restore from a relative time

In addition to restoring to a particular timestamp, you can also restore from a relative time, such as "ten minutes ago".

When you specify a relative time, you can specify any or all of days, hours, minutes, and seconds. For example:

"5m" to restore from five minutes ago
"1h" to restore from one hour ago
"3d" to restore from three days ago
"1h 5m" to restore from one hour and five minutes ago

Relative times can be in any of the following formats (again, note that you can specify any or all of days, hours, minutes, and seconds):

ISO 8601: 3d 4h 5m 6s
Abbreviated PostgreSQL: 3 d 4 hrs 5 mins 6 secs
Traditional PostgreSQL: 3 days 4 hours 5 minutes 6 seconds
SQL standard: D H:M:S

Refer to the yb-admin restore-snapshot-schedule command for more details.

Undo metadata changes

In addition to data changes, you can also use PITR to recover from metadata changes, such as creating, altering, and deleting tables and indexes.

Before you begin, if a local universe is currently running, first destroy it, and create a local multi-node YugabyteDB universe as described in Set up YugabyteDB universe.

Undo table creation

At a terminal prompt, create a snapshot schedule for the database. In this example, the schedule is on the default yugabyte database, one snapshot every minute, and each snapshot is retained for ten minutes:
sh
```
./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    create_snapshot_schedule 1 10 ysql.yugabyte
```
output.json
```
{
  "schedule_id": "1fb2d85a-3608-4cb1-af63-3e4062300dc1"
}
```

Verify that a snapshot has happened:

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    list_snapshot_schedules

output.json

{
    "schedules": [
        {
            "id": "1fb2d85a-3608-4cb1-af63-3e4062300dc1",
            "options": {
                "filter": "ysql.yugabyte",
                "interval": "1 min",
                "retention": "10 min"
            },
            "snapshots": [
                {
                    "id": "34b44c96-c340-4648-a764-7965fdcbd9f1",
                    "snapshot_time": "2023-04-20 00:20:38.214201"
                }
            ]
        }
    ]
}

To restore from an absolute time, get a timestamp from the command prompt. You'll create a table, then restore to this time to undo the table creation:
sh
```
python -c 'import datetime; print(datetime.datetime.now().strftime("%s%f"))'
```
output
```
1681964544554620
```
Start the YSQL shell and create a table as described in Create a table.

Restore the snapshot schedule to the timestamp you obtained before you created the table, at a terminal prompt:

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    restore_snapshot_schedule 1fb2d85a-3608-4cb1-af63-3e4062300dc1 1681964544554620

output.json

{
    "snapshot_id": "0f1582ea-c10d-4ad9-9cbf-e2313156002c",
    "restoration_id": "a61046a2-8b77-4d6e-87e1-1dc44b5ebc69"
}

Verify the restoration is in RESTORED state (you'll see more snapshots in the list, as well):

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    list_snapshots

output

Snapshot UUID                           State       Creation Time
34b44c96-c340-4648-a764-7965fdcbd9f1    COMPLETE    2023-04-20 00:20:38.214201
bacd0b53-6a51-4628-b898-e35116860735    COMPLETE    2023-04-20 00:21:43.221612
0f1582ea-c10d-4ad9-9cbf-e2313156002c    COMPLETE    2023-04-20 00:22:48.231456
617f9df8-3087-4b04-9187-399b52e738ee    COMPLETE    2023-04-20 00:23:53.239147
489e6903-2848-478b-9519-577084e49adf    COMPLETE    2023-04-20 00:24:58.246932
Restoration UUID                        State
a61046a2-8b77-4d6e-87e1-1dc44b5ebc69    RESTORED

Verify that the table no longer exists:

./bin/ysqlsh -d yugabyte;

sql

\d employees;

output

Did not find any relation named "employees".

Undo table deletion

Start the YSQL shell and create a table as described in Create a table.

Verify that a snapshot has happened since table creation:

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    list_snapshot_schedules

output.json

{
    "schedules": [
        {
            "id": "1fb2d85a-3608-4cb1-af63-3e4062300dc1",
            "options": {
                "filter": "ysql.yugabyte",
                "interval": "1 min",
                "retention": "10 min"
            },
            "snapshots": [
                {
                    "id": "34b44c96-c340-4648-a764-7965fdcbd9f1",
                    "snapshot_time": "2023-04-20 00:20:38.214201"
                },
                {
                    "id": "bacd0b53-6a51-4628-b898-e35116860735",
                    "snapshot_time": "2023-04-20 00:21:43.221612",
                    "previous_snapshot_time": "2023-04-20 00:20:38.214201"
                },
                [...]
                {
                    "id": "c98c890a-97ae-49f0-9c73-8d27c430874f",
                    "snapshot_time": "2023-04-20 00:28:13.287202",
                    "previous_snapshot_time": "2023-04-20 00:27:08.272905"
                }
            ]
        }
    ]
}

To restore from an absolute time, get a timestamp from the command prompt. You'll delete the table, then restore to this time to undo the delete:
sh
```
python -c 'import datetime; print(datetime.datetime.now().strftime("%s%f"))'
```
output
```
1681965106732671
```
In ysqlsh, drop this table:
sql
```
drop table employees;
```
output
```
DROP TABLE
```

Restore the snapshot schedule to the timestamp you obtained before you deleted the table, at a terminal prompt:

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    restore_snapshot_schedule 1fb2d85a-3608-4cb1-af63-3e4062300dc1 1681965106732671

output.json

{
    "snapshot_id": "fc95304a-b713-4468-a128-d5155c85333a",
    "restoration_id": "2bc005ca-c842-4c7c-9cc7-34e1f75ca467"
}

Verify the restoration is in RESTORED state (you'll see more snapshots in the list, as well):

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    list_snapshots

output

Snapshot UUID                           State       Creation Time
489e6903-2848-478b-9519-577084e49adf    COMPLETE    2023-04-20 00:24:58.246932
e4c12e39-6b15-49f2-97d1-86f777650d6b    COMPLETE    2023-04-20 00:26:03.257519
3d1176d0-f56d-44f3-bb29-2fcb9b08186b    COMPLETE    2023-04-20 00:27:08.272905
c98c890a-97ae-49f0-9c73-8d27c430874f    COMPLETE    2023-04-20 00:28:13.287202
17e9c8f7-2965-48d0-8459-c9dc90b8ed93    COMPLETE    2023-04-20 00:29:18.294031
e1900004-9a89-4c3a-b60b-4b570058c4da    COMPLETE    2023-04-20 00:30:23.306355
15ac0ae6-8ac2-4248-af69-756bb0abf534    COMPLETE    2023-04-20 00:31:28.319685
fc95304a-b713-4468-a128-d5155c85333a    COMPLETE    2023-04-20 00:32:33.332482
4a42a175-8065-4def-969a-b33ddc1bbdba    COMPLETE    2023-04-20 00:33:38.345533
Restoration UUID                        State
a61046a2-8b77-4d6e-87e1-1dc44b5ebc69    RESTORED
2bc005ca-c842-4c7c-9cc7-34e1f75ca467    RESTORED

Verify that the table exists with the data:

./bin/ysqlsh -d yugabyte;

sql

select * from employees;

output

 employee_no |      name      | department | salary
-------------+----------------+------------+--------
        1223 | Lucille Ball   | Operations |  70000
        1224 | John Zimmerman | Sales      |  60000
        1221 | John Smith     | Marketing  |  50000
        1222 | Bette Davis    | Sales      |  55000
(4 rows)

Undo table alteration

Undo column addition

Verify that a snapshot has happened since table restoration:

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    list_snapshot_schedules

output.json

{
    "schedules": [
        {
            "id": "1fb2d85a-3608-4cb1-af63-3e4062300dc1",
            "options": {
                "filter": "ysql.yugabyte",
                "interval": "1 min",
                "retention": "10 min"
            },
            "snapshots": [
                {
                    "id": "e4c12e39-6b15-49f2-97d1-86f777650d6b",
                    "snapshot_time": "2023-04-20 00:26:03.257519",
                    "previous_snapshot_time": "2023-04-20 00:24:58.246932"
                },
                {
                    "id": "3d1176d0-f56d-44f3-bb29-2fcb9b08186b",
                    "snapshot_time": "2023-04-20 00:27:08.272905",
                    "previous_snapshot_time": "2023-04-20 00:26:03.257519"
                },
                [...]
                {
                    "id": "d30fb638-6315-466a-a080-a6050e0dbb04",
                    "snapshot_time": "2023-04-20 00:34:43.358691",
                    "previous_snapshot_time": "2023-04-20 00:33:38.345533"
                }
            ]
        }
    ]
}

To restore from an absolute time, get a timestamp from the command prompt. You'll add a column to the table, then restore to this time in order to undo the column addition:
sh
```
python -c 'import datetime; print(datetime.datetime.now().strftime("%s%f"))'
```
output
```
1681965472490517
```

Using the same database, alter your table by adding a column:

sql

alter table employees add column v2 int;
select * from employees;

output

 employee_no |      name      | department | salary | v2
-------------+----------------+------------+--------+----
        1223 | Lucille Ball   | Operations |  70000 |
        1224 | John Zimmerman | Sales      |  60000 |
        1221 | John Smith     | Marketing  |  50000 |
        1222 | Bette Davis    | Sales      |  55000 |
(4 rows)

At a terminal prompt, restore the snapshot schedule to the timestamp you obtained before you added the column:

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    restore_snapshot_schedule 1fb2d85a-3608-4cb1-af63-3e4062300dc1 1681965472490517

output.json

{
    "snapshot_id": "b3c12c51-e7a3-41a5-bf0d-77cde8520527",
    "restoration_id": "470a8e0b-9fe4-418f-a13a-773bdedca013"
}

Verify the restoration is in RESTORED state (you'll see more snapshots in the list, as well):

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    list_snapshots

output

Snapshot UUID                           State       Creation Time
e1900004-9a89-4c3a-b60b-4b570058c4da    COMPLETE    2023-04-20 00:30:23.306355
15ac0ae6-8ac2-4248-af69-756bb0abf534    COMPLETE    2023-04-20 00:31:28.319685
fc95304a-b713-4468-a128-d5155c85333a    COMPLETE    2023-04-20 00:32:33.332482
4a42a175-8065-4def-969a-b33ddc1bbdba    COMPLETE    2023-04-20 00:33:38.345533
d30fb638-6315-466a-a080-a6050e0dbb04    COMPLETE    2023-04-20 00:34:43.358691
d228210b-cd87-4a74-bff6-42108f73456f    COMPLETE    2023-04-20 00:35:48.372783
390e4fec-8aa6-466d-827d-6bee435af5aa    COMPLETE    2023-04-20 00:36:53.394833
b3c12c51-e7a3-41a5-bf0d-77cde8520527    COMPLETE    2023-04-20 00:37:58.408458
d99317fe-6d20-4c7f-b469-ffb16409fbcf    COMPLETE    2023-04-20 00:39:03.419109
Restoration UUID                        State
a61046a2-8b77-4d6e-87e1-1dc44b5ebc69    RESTORED
2bc005ca-c842-4c7c-9cc7-34e1f75ca467    RESTORED
470a8e0b-9fe4-418f-a13a-773bdedca013    RESTORED

Check that the v2 column is gone:

sql

select * from employees;

output

 employee_no | name           | department | salary
-------------+----------------+------------+--------
        1223 |   Lucille Ball | Operations |  70000
        1224 | John Zimmerman |      Sales |  60000
        1221 |     John Smith |  Marketing |  50000
        1222 |    Bette Davis |      Sales |  55000

(4 rows)

Undo column deletion

To restore from an absolute time, get a timestamp from the command prompt. You'll remove a column from the table, then restore to this time to get the column back:
sh
```
python -c 'import datetime; print(datetime.datetime.now().strftime("%s%f"))'
```
output
```
1681965684502460
```

Using the same database, alter your table by dropping a column:

sql

alter table employees drop salary;
select * from employees;

output

 employee_no | name           | department
-------------+----------------+-----------
        1223 |   Lucille Ball | Operations
        1224 | John Zimmerman |      Sales
        1221 |     John Smith |  Marketing
        1222 |    Bette Davis |      Sales

(4 rows)

Restore the snapshot schedule to the timestamp you obtained before you dropped the column, at a terminal prompt.

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    restore_snapshot_schedule 1fb2d85a-3608-4cb1-af63-3e4062300dc1 1681965684502460

output

{
    "snapshot_id": "49311e65-cc5b-4d41-9f87-e84d630016a9",
    "restoration_id": "fe08826b-9b1d-4621-99ca-505d1d58e184"
}

Verify the restoration is in RESTORED state (you'll see more snapshots in the list, as well):

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    list_snapshots

output

Snapshot UUID                           State       Creation Time
4a42a175-8065-4def-969a-b33ddc1bbdba    COMPLETE    2023-04-20 00:33:38.345533
d30fb638-6315-466a-a080-a6050e0dbb04    COMPLETE    2023-04-20 00:34:43.358691
d228210b-cd87-4a74-bff6-42108f73456f    COMPLETE    2023-04-20 00:35:48.372783
390e4fec-8aa6-466d-827d-6bee435af5aa    COMPLETE    2023-04-20 00:36:53.394833
b3c12c51-e7a3-41a5-bf0d-77cde8520527    COMPLETE    2023-04-20 00:37:58.408458
d99317fe-6d20-4c7f-b469-ffb16409fbcf    COMPLETE    2023-04-20 00:39:03.419109
3f6651a5-00b2-4a9d-99e2-63b8b8e75ccf    COMPLETE    2023-04-20 00:40:08.432723
7aa1054a-1c96-4d33-bd37-02cdefaa5cad    COMPLETE    2023-04-20 00:41:13.445282
49311e65-cc5b-4d41-9f87-e84d630016a9    COMPLETE    2023-04-20 00:42:18.454674
Restoration UUID                        State
a61046a2-8b77-4d6e-87e1-1dc44b5ebc69    RESTORED
2bc005ca-c842-4c7c-9cc7-34e1f75ca467    RESTORED
470a8e0b-9fe4-418f-a13a-773bdedca013    RESTORED
fe08826b-9b1d-4621-99ca-505d1d58e184    RESTORED

Verify that the salary column is back:

sql

select * from employees;

output

 employee_no | name           | department | salary
-------------+----------------+------------+--------
        1223 |   Lucille Ball | Operations |  70000
        1224 | John Zimmerman |      Sales |  60000
        1221 |     John Smith |  Marketing |  50000
        1222 |    Bette Davis |      Sales |  55000

(4 rows)

Undo index creation

To restore from an absolute time, get a timestamp from the command prompt. You'll create an index on the table, then restore to this time to undo the index creation:
sh
```
python -c 'import datetime; print(datetime.datetime.now().strftime("%s%f"))'
```
output
```
1681965868912921
```

Create an index on the table:

sql

create index t1_index on employees (employee_no);
\d employees;

output

              Table "public.employees"
   Column    |  Type   | Collation | Nullable | Default
-------------+---------+-----------+----------+---------
 employee_no | integer |           | not null |
 name        | text    |           |          |
 department  | text    |           |          |
 salary      | integer |           |          |
 Indexes:
     "employees_pkey" PRIMARY KEY, lsm (employee_no HASH)
     "t1_index" lsm (employee_no HASH)

Restore the snapshot schedule to the timestamp you obtained before you created the index, at a terminal prompt:

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    restore_snapshot_schedule 1fb2d85a-3608-4cb1-af63-3e4062300dc1 1681965868912921

output

{
    "snapshot_id": "6a014fd7-5aad-4da0-883b-0c59a9261ed6",
    "restoration_id": "6698a1c4-58f4-48cb-8ec7-fa7b31ecca72"
}

Verify the restoration is in RESTORED state (you'll see more snapshots in the list, as well):

./bin/yb-admin \
    --master_addresses 127.0.0.1:7100,127.0.0.2:7100,127.0.0.3:7100 \
    list_snapshots

output

Snapshot UUID                           State       Creation Time
390e4fec-8aa6-466d-827d-6bee435af5aa    COMPLETE    2023-04-20 00:36:53.394833
b3c12c51-e7a3-41a5-bf0d-77cde8520527    COMPLETE    2023-04-20 00:37:58.408458
d99317fe-6d20-4c7f-b469-ffb16409fbcf    COMPLETE    2023-04-20 00:39:03.419109
3f6651a5-00b2-4a9d-99e2-63b8b8e75ccf    COMPLETE    2023-04-20 00:40:08.432723
7aa1054a-1c96-4d33-bd37-02cdefaa5cad    COMPLETE    2023-04-20 00:41:13.445282
49311e65-cc5b-4d41-9f87-e84d630016a9    COMPLETE    2023-04-20 00:42:18.454674
c6d37ea5-002e-4dff-b691-94d458f4b1f9    COMPLETE    2023-04-20 00:43:23.469233
98879e83-d507-496c-aa69-368fc2de8cf8    COMPLETE    2023-04-20 00:44:28.476244
6a014fd7-5aad-4da0-883b-0c59a9261ed6    COMPLETE    2023-04-20 00:45:33.467234
Restoration UUID                        State
a61046a2-8b77-4d6e-87e1-1dc44b5ebc69    RESTORED
2bc005ca-c842-4c7c-9cc7-34e1f75ca467    RESTORED
470a8e0b-9fe4-418f-a13a-773bdedca013    RESTORED
fe08826b-9b1d-4621-99ca-505d1d58e184    RESTORED
6698a1c4-58f4-48cb-8ec7-fa7b31ecca72    RESTORED

Verify that the index is gone:

sql

\d employees;

output

            Table "public.employees"
   Column    |  Type   | Collation | Nullable | Default
-------------+---------+-----------+----------+---------
 employee_no | integer |           | not null |
 name        | text    |           |          |
 department  | text    |           |          |
 salary      | integer |           |          |
 Indexes:
     "employees_pkey" PRIMARY KEY, lsm (employee_no HASH)

Along similar lines, you can undo index deletions and alter table rename columns.