feat(coprocessor): add transaction-based performance metrics

coprocessor/fhevm-engine/db-migration/migrations/20250929064611_create_transactions_table.sql

@@ -0,0 +1,27 @@
+-- Add transaction_id column to pbs_computations (if not present)
+ALTER TABLE pbs_computations
+ADD COLUMN IF NOT EXISTS transaction_id bytea NULL;
+CREATE INDEX IF NOT EXISTS idx_pbs_computations_transactions ON pbs_computations USING HASH (transaction_id);
+
+-- Add transaction_id column to allowed_handles (if not present)
+ALTER TABLE allowed_handles
+ADD COLUMN IF NOT EXISTS transaction_id bytea NULL;
+CREATE INDEX IF NOT EXISTS idx_allowed_handles_transactions ON allowed_handles USING HASH (transaction_id);
+
+-- Add transaction_id column to verify_proofs (if not present)
+ALTER TABLE verify_proofs
+ADD COLUMN IF NOT EXISTS transaction_id bytea NULL;
+CREATE INDEX IF NOT EXISTS idx_verify_proofs_transactions ON verify_proofs USING HASH (transaction_id);
+
+-- Add transaction_id column to ciphertext_digest (if not present)
+ALTER TABLE ciphertext_digest
+ADD COLUMN IF NOT EXISTS transaction_id bytea NULL;
+CREATE INDEX IF NOT EXISTS idx_ciphertext_digest_transactions ON ciphertext_digest USING HASH (transaction_id);
+
+CREATE TABLE transactions (
+    id BYTEA PRIMARY KEY,
+    chain_id BIGINT NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    block_number BIGINT NOT NULL,
+    completed_at TIMESTAMPTZ DEFAULT NULL
+);

coprocessor/fhevm-engine/db-migration/migrations/20251002083309_add_transactions_index.sql

@@ -0,0 +1,9 @@
+-- For completed txns
+CREATE INDEX idx_transactions_completed_createdat
+  ON transactions (created_at)
+  WHERE completed_at IS NOT NULL;
+
+-- For incomplete txns
+CREATE INDEX idx_transactions_incomplete_createdat
+  ON transactions (created_at)
+  WHERE completed_at IS NULL;

coprocessor/fhevm-engine/fhevm-engine-common/Cargo.toml

@@ -19,7 +19,7 @@ rand = { workspace = true }
 serde = { workspace = true }
 sha3 = { workspace = true }
 strum = { workspace = true }
-sqlx = {workspace = true}
+sqlx = {workspace = true, features = ["bigdecimal"]}
 tfhe = { workspace = true }
 tonic  = { workspace = true }
 tokio = { workspace = true }
@@ -30,6 +30,7 @@ axum = { workspace = true}
 serde_json = { workspace = true}
 http = {workspace = true}
 thiserror = { workspace = true }
+prometheus = { workspace = true }
 
 
 # crates.io dependencies