<p>
The message that using "statement" variant specifies the name of an existing prepared statement.
<p>
The response is a {@link ParamDesc} message describing the parameters needed by the statement,
followed by a {@link RowDesc} message describing the rows that will be returned when the statement is eventually
executed or a {@link NoData} message if the statement will not return rows.
{@link ErrorResponse} is issued if there is no such prepared statement.
<p>
Note that since {@link Bind} has not yet been issued, the formats to be used for returned columns are not yet known to
the backend; the format code fields in the {@link RowDesc} message will be zeroes in this case.
<p>
The message that using "portal" variant specifies the name of an existing portal.
<p>
The response is a {@link RowDesc} message describing the rows that will be returned by executing the portal;
or a {@link NoData} message if the portal does not contain a query that will return rows; or {@link ErrorResponse}
if there is no such portal.
<p> The message that using "statement" variant specifies the name of an existing prepared statement. <p> The response is a {@link ParamDesc} message describing the parameters needed by the statement, followed by a {@link RowDesc} message describing the rows that will be returned when the statement is eventually executed or a {@link NoData} message if the statement will not return rows. {@link ErrorResponse} is issued if there is no such prepared statement. <p> Note that since {@link Bind} has not yet been issued, the formats to be used for returned columns are not yet known to the backend; the format code fields in the {@link RowDesc} message will be zeroes in this case. <p> The message that using "portal" variant specifies the name of an existing portal. <p> The response is a {@link RowDesc} message describing the rows that will be returned by executing the portal; or a {@link NoData} message if the portal does not contain a query that will return rows; or {@link ErrorResponse} if there is no such portal.