SAVEPOINT

reference

The SAVEPOINT statement enables you to set a savepoint within a transaction.

Purpose

The SAVEPOINT statement enables you to set a savepoint within an ACID transaction. Refer to SQL++ Support for Couchbase Transactions for further information.

This statement may only be used within a transaction.

If you are using the Query REST API, you must set the txid query parameter to specify the transaction ID.

If you are using the Query Workbench, you don’t need to specify the transaction ID, as long as the statement is part of a multi-statement request. When you start a transaction within a multi-statement request, all statements within the request are assumed to be part of the same transaction until you rollback or commit the transaction.

Similarly, if you are using the cbq shell, you don’t need to specify the transaction ID. Once you have started a transaction, all statements within the cbq shell session are assumed to be part of the same transaction until you rollback or commit the transaction. ^[1]

Syntax

savepoint ::= 'SAVEPOINT' savepointname

savepointname: An identifier specifying a name for the savepoint.

If a savepoint with the same name already exists, the existing savepoint is replaced.

Example

If you want to try this example, first refer to Preparation to set up your environment.

Example 1. Set savepoints

Transaction

-- Start the transaction
BEGIN TRANSACTION;

-- Specify transaction settings
SET TRANSACTION ISOLATION LEVEL READ COMMITTED;

-- Create a booking document
UPSERT INTO bookings
VALUES("bf7ad6fa-bdb9-4099-a840-196e47179f03", {
  "date": "07/24/2021",
  "flight": "WN533",
  "flighttime": 7713,
  "price": 964.13,
  "route": "63986"
});

-- Set a savepoint
SAVEPOINT s1;

-- Update the booking document to include a user
UPDATE bookings AS b
USE KEYS "bf7ad6fa-bdb9-4099-a840-196e47179f03"
SET b.`user` = "0";

-- Check the content of the booking and user
SELECT b.*, u.name
FROM bookings b
USE KEYS "bf7ad6fa-bdb9-4099-a840-196e47179f03"
JOIN users u
ON KEYS b.`user`;

-- Set a second savepoint
SAVEPOINT s2;

-- Update the booking documents to change the user
UPDATE bookings AS b
USE KEYS "bf7ad6fa-bdb9-4099-a840-196e47179f03"
SET b.`user` = "1";

-- Check the content of the booking and user
SELECT b.*, u.name
FROM bookings b
USE KEYS "bf7ad6fa-bdb9-4099-a840-196e47179f03"
JOIN users u
ON KEYS b.`user`;

-- Roll back the transaction to the second savepoint
ROLLBACK TRANSACTION TO SAVEPOINT s2;

-- Check the content of the booking and user again
SELECT b.*, u.name
FROM bookings b
USE KEYS "bf7ad6fa-bdb9-4099-a840-196e47179f03"
JOIN users u
ON KEYS b.`user`;

-- Commit the transaction
COMMIT TRANSACTION;

Results

[
  {
    "_sequence_num": 1,
    "_sequence_query": "-- Start the transaction\nBEGIN TRANSACTION;",
    "_sequence_query_status": "success",
    "_sequence_result": [
      {
        "txid": "d81d9b4a-b758-4f98-b007-87ba262d3a51" (1)
      }
    ]
  },
  {
    "_sequence_num": 2,
    "_sequence_query": "\n\n-- Specify transaction settings\nSET TRANSACTION ISOLATION LEVEL READ COMMITTED;",
    "_sequence_query_status": "success",
    "_sequence_result": {
      "results": []
    }
  },
  {
    "_sequence_num": 3,
    "_sequence_query": "\n\n-- Create a booking document\nUPSERT INTO bookings\nVALUES(\"bf7ad6fa-bdb9-4099-a840-196e47179f03\", {\n  \"date\": \"07/24/2021\",\n  \"flight\": \"WN533\",\n  \"flighttime\": 7713,\n  \"price\": 964.13,\n  \"route\": \"63986\"\n});",
    "_sequence_query_status": "success",
    "_sequence_result": {
      "results": []
    }
  },
  {
    "_sequence_num": 4,
    "_sequence_query": "\n\n-- Set a savepoint\nSAVEPOINT s1;",
    "_sequence_query_status": "success",
    "_sequence_result": {
      "results": []
    }
  },
  {
    "_sequence_num": 5,
    "_sequence_query": "\n\n-- Update the booking document to include a user\nUPDATE bookings AS b\nUSE KEYS \"bf7ad6fa-bdb9-4099-a840-196e47179f03\"\nSET b.`user` = \"0\";",
    "_sequence_query_status": "success",
    "_sequence_result": {
      "results": []
    }
  },
  {
    "_sequence_num": 6,
    "_sequence_query": "\n\n-- Check the content of the booking and user\nSELECT b.*, u.name\nFROM bookings b\nUSE KEYS \"bf7ad6fa-bdb9-4099-a840-196e47179f03\"\nJOIN users u\nON KEYS b.`user`;",
    "_sequence_query_status": "success",
    "_sequence_result": [
      {
        "date": "07/24/2021",
        "flight": "WN533",
        "flighttime": 7713,
        "price": 964.13,
        "route": "63986",
        "user": "0", (2)
        "name": "Keon Hoppe"
      }
    ]
  },
  {
    "_sequence_num": 7,
    "_sequence_query": "\n\n-- Set a second savepoint\nSAVEPOINT s2;",
    "_sequence_query_status": "success",
    "_sequence_result": {
      "results": []
    }
  },
  {
    "_sequence_num": 8,
    "_sequence_query": "\n\n-- Update the booking documents to change the user\nUPDATE bookings AS b\nUSE KEYS \"bf7ad6fa-bdb9-4099-a840-196e47179f03\"\nSET b.`user` = \"1\";",
    "_sequence_query_status": "success",
    "_sequence_result": {
      "results": []
    }
  },
  {
    "_sequence_num": 9,
    "_sequence_query": "\n\n-- Check the content of the booking and user\nSELECT b.*, u.name\nFROM bookings b\nUSE KEYS \"bf7ad6fa-bdb9-4099-a840-196e47179f03\"\nJOIN users u\nON KEYS b.`user`;",
    "_sequence_query_status": "success",
    "_sequence_result": [
      {
        "date": "07/24/2021",
        "flight": "WN533",
        "flighttime": 7713,
        "price": 964.13,
        "route": "63986",
        "user": "1", (3)
        "name": "Rigoberto Bernier"
      }
    ]
  },
  {
    "_sequence_num": 10,
    "_sequence_query": "\n\n-- Roll back the transaction to the second savepoint\nROLLBACK TRANSACTION TO SAVEPOINT s2;",
    "_sequence_query_status": "success",
    "_sequence_result": {
      "results": []
    }
  },
  {
    "_sequence_num": 11,
    "_sequence_query": "\n\n-- Check the content of the booking and user again\nSELECT b.*, u.name\nFROM bookings b\nUSE KEYS \"bf7ad6fa-bdb9-4099-a840-196e47179f03\"\nJOIN users u\nON KEYS b.`user`;",
    "_sequence_query_status": "success",
    "_sequence_result": [
      {
        "date": "07/24/2021",
        "flight": "WN533",
        "flighttime": 7713,
        "price": 964.13,
        "route": "63986",
        "user": "0", (4)
        "name": "Keon Hoppe"
      }
    ]
  },
  {
    "_sequence_num": 12,
    "_sequence_query": "\n\n-- Commit the transaction\nCOMMIT TRANSACTION;",
    "_sequence_query_status": "success",
    "_sequence_result": {
      "results": []
    }
  }
]

1	Beginning a transaction returns a transaction ID.
2	Before setting the second savepoint, the booking document has user `"0"`, name `"Keon Hoppe"`.
3	After setting the second savepoint and performing an update, the booking document has user `"1"`, name `"Rigoberto Bernier"`.
4	After rolling back to the second savepoint, the booking document again has user `"0"`, name `"Keon Hoppe"`.

For an overview of Couchbase transactions, refer to Transactions.
To begin a transaction, refer to BEGIN TRANSACTION.
To specify transaction settings, refer to SET TRANSACTION.
To rollback a transaction, refer to ROLLBACK TRANSACTION.
To commit a transaction, refer to COMMIT TRANSACTION.
Blog post: Couchbase Transactions: Elastic, Scalable, and Distributed.

1. You must be using cbq shell version 2.0 or above to use the automatic transaction ID functionality.

SAVEPOINT

Purpose

Syntax

Example

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