Fix max db size inconsistency.

Change-Id: Id07007f28db88920d4881fe4f98ccba1ff956d98

Author: Changochen

oak_private_memory/app/db_client.rs

@@ -18,12 +18,13 @@ use std::net::SocketAddr;
 use anyhow::bail;
 use log::info;
 use metrics::get_global_metrics;
+pub use oak_private_memory_database::database_with_cache::MAX_DECODE_SIZE;
 use sealed_memory_grpc_proto::oak::private_memory::sealed_memory_database_service_client::SealedMemoryDatabaseServiceClient;
 use tokio::sync::RwLock;
 use tonic::transport::{Channel, Endpoint};
+
 const MAX_CONNECT_RETRIES: usize = 5;
 const INITIAL_BACKOFF_MS: u64 = 100;
-pub const MAX_DECODE_SIZE: usize = 100 * 1024 * 1024; // 100 MB
 
 pub struct SharedDbClient {
     database_service_host: SocketAddr,

oak_private_memory/database/database_with_cache.rs

@@ -26,8 +26,9 @@ use crate::{
     memory_cache::MemoryCache,
 };
 
-const DATABASE_MAX_SIZE: usize = 1024 * 1024 * 1024; // 1 GB
-
+// We limit the decode size to 100 MB and use this limit as the max size of the
+// database.
+pub const MAX_DECODE_SIZE: usize = 100 * 1024 * 1024; // 100 MB
 /// A database with cache. It loads the meta database of the user at start,
 /// then loads documents at request. The loaded documents will be then cached
 /// in memory.
@@ -52,7 +53,7 @@ impl DatabaseWithCache {
             cache: MemoryCache::new(db_client, dek),
             key_derivation_info,
             current_size: initial_size,
-            max_size: DATABASE_MAX_SIZE,
+            max_size: MAX_DECODE_SIZE,
         }
     }