Issue #3185399 by alexpott, mondrake, daffie: Use RETURNING to determine last...

namespace Drupal\Core\Database\Driver\pgsql;

use Drupal\Core\Database\Database;

use Drupal\Core\Database\DatabaseExceptionWrapper;

use Drupal\Core\Database\IntegrityConstraintViolationException;

use Drupal\Core\Database\Query\Insert as QueryInsert;

          if ($serial_key !== FALSE) {

            $serial_value = $insert_values[$serial_key];

            // Force $last_insert_id to the specified value. This is only done

            // if $index is 0.

            if ($index == 0) {

              $last_insert_id = $serial_value;

            }

            // Sequences must be greater than or equal to 1.

            if ($serial_value === NULL || !$serial_value) {

              $serial_value = 1;

      }

    }

    // PostgreSQL requires the table name to be specified explicitly when

    // requesting the last insert ID. If there are no sequences, then we can't

    // get a last insert id.

    $sequence_name = $table_information->sequences[0] ?? NULL;

    // Create a savepoint so we can rollback a failed query. This is so we can

    // mimic MySQL and SQLite transactions which don't fail if a single query

    // fails. This is important for tables that are created on demand. For

    $this->connection->addSavepoint();

    try {

      $stmt->execute(NULL, $this->queryOptions);

      // Only use the returned last_insert_id if it is not already set.

      // PostgreSQL requires the table name to be specified explicitly when

      // requesting the last insert ID.

      if (!isset($last_insert_id)) {

        if ($this->queryOptions['return'] === Database::RETURN_INSERT_ID && $sequence_name !== NULL) {

          // cspell:ignore currval

          $last_insert_id = $this->connection->query("SELECT currval('$sequence_name')")->fetchField();

        }

        else {

          $last_insert_id = NULL;

        }

      if (isset($table_information->serial_fields[0])) {

        $last_insert_id = $stmt->fetchField();

      }

      $this->connection->releaseSavepoint();

    }

    // Re-initialize the values array so that we can re-use this query.

    $this->insertValues = [];

    return $last_insert_id;

    return $last_insert_id ?? NULL;

  }

  public function __toString() {

    // pass it back, as any remaining options are irrelevant.

    if (!empty($this->fromQuery)) {

      $insert_fields_string = $insert_fields ? ' (' . implode(', ', $insert_fields) . ') ' : ' ';

      return $comments . 'INSERT INTO {' . $this->table . '}' . $insert_fields_string . $this->fromQuery;

      $query = $comments . 'INSERT INTO {' . $this->table . '}' . $insert_fields_string . $this->fromQuery;

    }

    else {

      $query = $comments . 'INSERT INTO {' . $this->table . '} (' . implode(', ', $insert_fields) . ') VALUES ';

      $values = $this->getInsertPlaceholderFragment($this->insertValues, $this->defaultFields);

      $query .= implode(', ', $values);

    }

    try {

      // Fetch the list of blobs and sequences used on that table.

      $table_information = $this->connection->schema()->queryTableInformation($this->table);

      if (isset($table_information->serial_fields[0])) {

        // Use RETURNING syntax to get the last insert ID in the same INSERT

        // query, see https://www.postgresql.org/docs/10/dml-returning.html.

        $query .= ' RETURNING ' . $table_information->serial_fields[0];

      }

    }

    catch (DatabaseExceptionWrapper $e) {

      // If we fail to get the table information it is probably because the

      // table does not exist yet so adding the returning statement is pointless

      // because the query will fail. This happens for tables created on demand,

      // for example, cache tables.

    }

    return $query;

  }