As enterprises move to cloud-based analytics, the risk of cloud security breaches poses a serious threat. Encrypting data at rest and in transit is a major first step. However, data must still be decrypted in memory for processing, exposing it to an attacker who has compromised the operating system or hypervisor. Trusted hardware such as Intel SGX has recently become available in latest-generation processors. Such hardware enables arbitrary computation on encrypted data while shielding it from a malicious OS or hypervisor. However, it still suffers from a significant side channel: access pattern leakage. We present Opaque, a package for Apache Spark SQL that enables very strong security for SQL queries: data encryption, computation verification, and access pattern leakage protection (a.k.a. obliviousness). Opaque achieves these guarantees by introducing new oblivious distributed relational operators that provide 2000x performance gain over state of the art oblivious systems, as well as novel query planning techniques for these operators implemented using Catalyst.