Oral argument on any motion in any prisoner civil action shall be heard orally only at the request of the court; whenever possible, the court shall rule upon the record before it. No prisoner shall be permitted to request subpoenas for witnesses or documents, or file discovery requests, until the court has ruled upon any demurrer, plea or motion to dismiss. Where a case proceeds past the initial dispositive motions, the court shall require the prisoner seeking discovery to demonstrate that his requests are relevant and material to the issues in the case. No subpoena for witnesses or documents shall issue unless a judge of the court has reviewed the subpoena request and specifically authorized a subpoena to issue. The court shall exercise its discretion in determining the scope of the subpoena and may condition its issuance on such terms as the court finds appropriate. The court shall take into account the burden placed upon the object of the subpoena in relation to the needs of the case, the amount in controversy, and the importance of the issues at stake in the litigation.