Operations · 2 min read

BulkDeleteByKey

This method deletes rows from the database using a list of primary keys in bulk. It is supported only for CockroachDB.

Call Flow Diagram

The diagram below shows the flow when calling this operation.

flowchart TD
    Client["Client<br/>(RepoDB)"] -->|BulkDeleteByKey| Keys["Primary Keys<br/>IEnumerable&lt;TPrimaryKey&gt;"]
    Keys --> Pseudo["Create Pseudo Table<br/>(Memory by default,<br/>key column only) + index"]
    Pseudo --> Copy["CockroachDbBulkCopy"]
    Copy -->|Write| PseudoTable[("Pseudo Table")]
    PseudoTable -->|"DELETE ... USING Pseudo<br/>WHERE (key match)"| Table[("Target Table")]
    PseudoTable -->|Drop| Cleanup(["Pseudo Table Dropped"])

Use Case

Use this method to delete rows by primary key at high speed. It leverages CockroachDbBulkCopy, a native binary COPY-based bulk writer from RepoDb.Connector.CockroachDb.

Special Arguments

The bulkCopyTimeout, batchSize and pseudoTableType arguments are available for this operation.

batchSize overrides the number of rows sent to the server per batch. When not set, all items are sent at once.

pseudoTableType (via CockroachDbBulkImportPseudoTableType) controls the kind of staging table used internally.

Usability

Pass the target table name and the list of primary keys to the operation.

using (var connection = new CockroachDbConnection(connectionString))
{
    var primaryKeys = connection.Query<Person>(p => p.IsActive == false).Select(p => p.Id);
    var deletedRows = connection.BulkDeleteByKey("Person", primaryKeys);
}

It returns the number of rows deleted from the underlying table.

To specify a batch size:

using (var connection = new CockroachDbConnection(connectionString))
{
    var primaryKeys = connection.Query<Person>(p => p.IsActive == false).Select(p => p.Id);
    var deletedRows = connection.BulkDeleteByKey("Person",
        primaryKeys,
        batchSize: 100);
}

Async Method

An equivalent BulkDeleteByKeyAsync method is also available.

using (var connection = new CockroachDbConnection(connectionString))
{
    var primaryKeys = connection.Query<Person>(p => p.IsActive == false).Select(p => p.Id);
    var deletedRows = await connection.BulkDeleteByKeyAsync("Person", primaryKeys);
}