oci_set_prefetch_lob

Sets the amount of data prefetched for each CLOB or BLOB.

&reftitle.description; `bool` `oci_set_prefetch_lob` `resource` `statement` `int` `prefetch_lob_size`

Sets the internal buffer size used to fetch each CLOB or BLOB value when the implementation gets the internal Oracle LOB locator from the database after a successful query call to `oci_execute` and for each subsequent internal fetch request to the database. Increasing this value can improve the performance of fetching smaller LOBs by reducing round-trips between PHP and the database. Memory usage will change.

The value affects LOBs returned as OCILob instances and also those returned using `OCI_RETURN_LOBS`.

Call `oci_set_prefetch_lob` before calling `oci_execute`. If it is not called, the value of oci8.prefetch_lob_size is used.

The LOB prefetch value should only be set with Oracle Database 12.2 or later.

&reftitle.parameters;

`statement`

- &oci.arg.statement.id;

`prefetch_lob_size`

- The number of bytes of each LOB to be prefetched, >= 0

&reftitle.returnvalues;

&return.success;

&reftitle.examples;

### Changing the LOB prefetch value for a query

    <?php

    $conn = oci_connect('hr', 'welcome', 'localhost/XE');

    $stid = oci_parse($conn, 'SELECT myclob FROM mytable');
    oci_set_prefetch_lob($stid, 100000);  // Set before calling oci_execute()
    oci_execute($stid);

    echo "<table border='1'>\n";
    while ($row = oci_fetch_array($stid, OCI_ASSOC+OCI_RETURN_NULLS+OCI_RETURN_LOBS)) {
        echo "<tr>\n";
        foreach ($row as $item) {
            echo "    <td>".($item !== null ? htmlentities($item, ENT_QUOTES) : "&nbsp;")."</td>\n";
        }
        echo "</tr>\n";
    }
    echo "</table>\n";

    oci_free_statement($stid);
    oci_close($conn);

    ?>

&reftitle.seealso;

- oci8.prefetch_lob_size ini option