John Davidson

Message:

I am trying to create a function that exports the mysql database. I researched many ways to do that. I have arrived to the function below. The problem with this is the exporting is so slow my database size is only 10mb. Is there a way to make this faster or improve it?

public function backup_database($tables = '*'){

    if ($this->databaseConnection()) {

        $return = '';



        if($tables == '*') {

            $tables = array();



            $sql = $this->db_connection->prepare('SHOW TABLES');



            if($sql->execute()){

                while($row = $sql->fetch()){

                    $tables[] = $row[0];

                }

            }

        }

        else {

            $tables = is_array($tables) ? $tables : explode(',',$tables);

        }



        foreach($tables as $table) {

            $result = $this->db_connection->prepare('SELECT * FROM ' . $table);

            $result->execute();

            $num_fields = $result->rowCount();



            $return .= 'DROP TABLE ' . $table . ';';



            $row2 = $this->db_connection->prepare('SHOW CREATE TABLE '.$table);

            $row2->execute();

            $row2 = $row2->fetch();



            $return .= "\n\n".$row2[1].";\n\n";



            for ($i = 0; $i < $num_fields; $i++){

                while($row = $result->fetch())

                {

                    $return .= 'INSERT INTO '. $table .' VALUES(';

                    for($j = 0; $j < $num_fields; $j++){

                        $row[$j] = addslashes($row[$j]);

                        $row[$j] = preg_replace("/\\n/","\\n",$row[$j]);

                        if (isset($row[$j])) { $return .= '"'. $row[$j] .'"' ; } else { $return .= '""'; }

                        if ($j<($num_fields-1)) { $return .= ','; }

                    }

                    $return .= ");\n";

                }

            }



            $return .="\n\n\n";

        }



        if (!file_exists('database_backups')) {

            mkdir('database_backups', 0777, true);

        }

        

        $filename = 'database_backups/db-backup-'.time().'-'.(md5(implode(',',$tables))).'.sql.gz';

        $handle = fopen($filename,'w+');

        $gzdata = gzencode($return, 9);

        fwrite($handle,$gzdata);

        fclose($handle);

        

        return '1';

    }

---

My Answer:
To improve the export speed of your database using PHP, you can consider the following optimizations:

1. Use mysqldump: Instead of fetching each row individually using SELECT queries, you can use the mysqldump command-line tool to export the entire database in a single command. This will be much faster than fetching rows one by one in PHP.

2. Increase memory limit and execution time: If you are dealing with large databases, you may need to increase the memory limit and execution time in your PHP configuration to handle the export process efficiently.

3. Use batch processing: Instead of fetching and inserting all rows at once, you can process the data in batches to reduce memory usage and improve performance. You can fetch a certain number of rows at a time and insert them into the export file before moving on to the next batch.

4. Optimize SQL queries: Make sure your SQL queries are optimized for performance. Use indexes, limit the number of columns selected, and avoid unnecessary joins to speed up the export process.

5. Compress the export file: Compressing the export file using gzip or another compression algorithm can reduce the file size and improve the overall export speed.

By implementing these optimizations, you should be able to improve the export speed of your database using PHP.