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 N1QL 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
    Syntax diagram: refer to source code listing
    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 WORK;
    
    -- Specify transaction settings
    SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
    
    -- Create a booking document
    UPSERT INTO `travel-sample`.tenant_agent_00.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 `travel-sample`.tenant_agent_00.bookings AS b
    SET b.`user` = "0"
    WHERE META(b).id = "bf7ad6fa-bdb9-4099-a840-196e47179f03";
    
    -- Check the content of the booking and user
    SELECT b.*, u.name
    FROM `travel-sample`.tenant_agent_00.bookings b
    JOIN `travel-sample`.tenant_agent_00.users u
    ON b.`user` = META(u).id
    WHERE META(b).id = "bf7ad6fa-bdb9-4099-a840-196e47179f03";
    
    -- Set a second savepoint
    SAVEPOINT s2;
    
    -- Update the booking documents to change the user
    UPDATE `travel-sample`.tenant_agent_00.bookings AS b
    SET b.`user` = "1"
    WHERE META(b).id = "bf7ad6fa-bdb9-4099-a840-196e47179f03";
    
    -- Check the content of the booking and user
    SELECT b.*, u.name
    FROM `travel-sample`.tenant_agent_00.bookings b
    JOIN `travel-sample`.tenant_agent_00.users u
    ON b.`user` = META(u).id
    WHERE META(b).id = "bf7ad6fa-bdb9-4099-a840-196e47179f03";
    
    -- Roll back the transaction to the second savepoint
    ROLLBACK TRAN TO SAVEPOINT s2;
    
    -- Check the content of the booking and user again
    SELECT b.*, u.name
    FROM `travel-sample`.tenant_agent_00.bookings b
    JOIN `travel-sample`.tenant_agent_00.users u
    ON b.`user` = META(u).id
    WHERE META(b).id = "bf7ad6fa-bdb9-4099-a840-196e47179f03";
    
    -- Commit the transaction
    COMMIT WORK;
    Results
    [
      {
        "_sequence_num": 1,
        "_sequence_query": "-- Start the transaction\nBEGIN WORK;",
        "_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 `travel-sample`.tenant_agent_00.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 `travel-sample`.tenant_agent_00.bookings AS b\nSET b.`user` = \"0\"\nWHERE META(b).id = \"bf7ad6fa-bdb9-4099-a840-196e47179f03\";",
        "_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 `travel-sample`.tenant_agent_00.bookings b\nJOIN `travel-sample`.tenant_agent_00.users u\nON b.`user` = META(u).id\nWHERE META(b).id = \"bf7ad6fa-bdb9-4099-a840-196e47179f03\";",
        "_sequence_query_status": "success",
        "_sequence_result": [
          {
            "date": "07/24/2021",
            "flight": "WN533",
            "flighttime": 7713,
            "name": "Keon Hoppe",
            "price": 964.13,
            "route": "63986",
            "user": "0" (2)
          }
        ]
      },
      {
        "_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 `travel-sample`.tenant_agent_00.bookings AS b\nSET b.`user` = \"1\"\nWHERE META(b).id = \"bf7ad6fa-bdb9-4099-a840-196e47179f03\";",
        "_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 `travel-sample`.tenant_agent_00.bookings b\nJOIN `travel-sample`.tenant_agent_00.users u\nON b.`user` = META(u).id\nWHERE META(b).id = \"bf7ad6fa-bdb9-4099-a840-196e47179f03\";",
        "_sequence_query_status": "success",
        "_sequence_result": [
          {
            "date": "07/24/2021",
            "flight": "WN533",
            "flighttime": 7713,
            "name": "Rigoberto Bernier",
            "price": 964.13,
            "route": "63986",
            "user": "1" (3)
          }
        ]
      },
      {
        "_sequence_num": 10,
        "_sequence_query": "\n\n-- Roll back the transaction to the second savepoint\nROLLBACK TRAN 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 `travel-sample`.tenant_agent_00.bookings b\nJOIN `travel-sample`.tenant_agent_00.users u\nON b.`user` = META(u).id\nWHERE META(b).id = \"bf7ad6fa-bdb9-4099-a840-196e47179f03\";",
        "_sequence_query_status": "success",
        "_sequence_result": [
          {
            "date": "07/24/2021",
            "flight": "WN533",
            "flighttime": 7713,
            "name": "Keon Hoppe",
            "price": 964.13,
            "route": "63986",
            "user": "0" (4)
          }
        ]
      },
      {
        "_sequence_num": 12,
        "_sequence_query": "\n\n-- Commit the transaction\nCOMMIT WORK;",
        "_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".

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