Constant zebra_consensus::primitives::halo2::HALO2_MAX_BATCH_SIZE

const HALO2_MAX_BATCH_SIZE: usize = 2;

Adjusted batch size for halo2 batches.

Unlike other batch verifiers, halo2 has aggregate proofs. This means that there can be hundreds of actions verified by some proofs, but just one action in others.

To compensate for larger proofs, we decrease the batch size.

We also decrease the batch size for these reasons:

• the default number of actions in zcashd is 2,
• halo2 proofs take longer to verify than Sapling proofs, and
• transactions with many actions generate very large proofs.

TODO

Count each halo2 action as a batch item. We could increase the batch item count by the action count each time a batch request is received, which would reduce batch size, but keep the batch queue size larger.