Same name in this branch

1. 9 core/modules/sqlite/src/Driver/Database/sqlite/Connection.php \Drupal\sqlite\Driver\Database\sqlite\Connection::nextId()
2. 9 core/modules/mysql/src/Driver/Database/mysql/Connection.php \Drupal\mysql\Driver\Database\mysql\Connection::nextId()
3. 9 core/tests/fixtures/database_drivers/custom/fake/Connection.php \Drupal\Driver\Database\fake\Connection::nextId()
4. 9 core/lib/Drupal/Core/Database/Connection.php \Drupal\Core\Database\Connection::nextId()

Same name and namespace in other branches

1. 8.9.x core/tests/fixtures/database_drivers/custom/fake/Connection.php \Drupal\Driver\Database\fake\Connection::nextId()
2. 8.9.x core/lib/Drupal/Core/Database/Driver/sqlite/Connection.php \Drupal\Core\Database\Driver\sqlite\Connection::nextId()
3. 8.9.x core/lib/Drupal/Core/Database/Driver/mysql/Connection.php \Drupal\Core\Database\Driver\mysql\Connection::nextId()
4. 8.9.x core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php \Drupal\Core\Database\Driver\pgsql\Connection::nextId()
5. 8.9.x core/lib/Drupal/Core/Database/Connection.php \Drupal\Core\Database\Connection::nextId()
6. 10 core/modules/sqlite/src/Driver/Database/sqlite/Connection.php \Drupal\sqlite\Driver\Database\sqlite\Connection::nextId()
7. 10 core/modules/mysql/src/Driver/Database/mysql/Connection.php \Drupal\mysql\Driver\Database\mysql\Connection::nextId()
8. 10 core/modules/pgsql/src/Driver/Database/pgsql/Connection.php \Drupal\pgsql\Driver\Database\pgsql\Connection::nextId()
9. 10 core/tests/fixtures/database_drivers/custom/fake/Connection.php \Drupal\Driver\Database\fake\Connection::nextId()
10. 10 core/lib/Drupal/Core/Database/Connection.php \Drupal\Core\Database\Connection::nextId()

Retrieve a the next id in a sequence.

PostgreSQL has built in sequences. We'll use these instead of inserting and updating a sequences table.

Parameters

$existing_id: (optional) After a database import, it might be that the sequences table is behind, so by passing in the maximum existing ID, it can be assured that we never issue the same ID.

Return value

int|string An integer number larger than any number returned by earlier calls and also larger than the $existing_id if one was passed in.

Overrides Connection::nextId

File

core/modules/pgsql/src/Driver/Database/pgsql/Connection.php, line 274

Class

Connection

PostgreSQL implementation of \Drupal\Core\Database\Connection.

Namespace

Drupal\pgsql\Driver\Database\pgsql

Code

public function nextId($existing = 0) {
    // Retrieve the name of the sequence. This information cannot be cached
    // because the prefix may change, for example, like it does in tests.
    $sequence_name = $this->makeSequenceName('sequences', 'value');
    // When PostgreSQL gets a value too small then it will lock the table,
    // retry the INSERT and if it's still too small then alter the sequence.
    $id = $this->query("SELECT nextval('" . $sequence_name . "')")
        ->fetchField();
    if ($id > $existing) {
        return $id;
    }
    // PostgreSQL advisory locks are simply locks to be used by an
    // application such as Drupal. This will prevent other Drupal processes
    // from altering the sequence while we are.
    $this->query("SELECT pg_advisory_lock(" . self::POSTGRESQL_NEXTID_LOCK . ")");
    // While waiting to obtain the lock, the sequence may have been altered
    // so lets try again to obtain an adequate value.
    $id = $this->query("SELECT nextval('" . $sequence_name . "')")
        ->fetchField();
    if ($id > $existing) {
        $this->query("SELECT pg_advisory_unlock(" . self::POSTGRESQL_NEXTID_LOCK . ")");
        return $id;
    }
    // Reset the sequence to a higher value than the existing id.
    $this->query("ALTER SEQUENCE " . $sequence_name . " RESTART WITH " . ($existing + 1));
    // Retrieve the next id. We know this will be as high as we want it.
    $id = $this->query("SELECT nextval('" . $sequence_name . "')")
        ->fetchField();
    $this->query("SELECT pg_advisory_unlock(" . self::POSTGRESQL_NEXTID_LOCK . ")");
    return $id;
}

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