diff --git a/crates/bindings-typescript/src/sdk/db_connection_impl.ts b/crates/bindings-typescript/src/sdk/db_connection_impl.ts
index c2c26123bfe..ffef108d936 100644
--- a/crates/bindings-typescript/src/sdk/db_connection_impl.ts
+++ b/crates/bindings-typescript/src/sdk/db_connection_impl.ts
@@ -158,6 +158,10 @@ export class DbConnectionImpl<RemoteModule extends UntypedRemoteModule>
   #reducerCallInfo = new Map<number, { name: string; args: object }>();
   #procedureCallbacks = new Map<number, ProcedureCallback>();
   #rowDeserializers: Record<string, Deserializer<any>>;
+  #rowIdMetadata: Record<
+    string,
+    { primaryKeyColName?: string; primaryKeyColType?: AlgebraicType }
+  >;
   #reducerArgsSerializers: Record<
     string,
     { serialize: Serializer<any>; deserialize: Deserializer<any> }
@@ -205,6 +209,7 @@ export class DbConnectionImpl<RemoteModule extends UntypedRemoteModule>
     this.#emitter = emitter;
 
     this.#rowDeserializers = Object.create(null);
+    this.#rowIdMetadata = Object.create(null);
     this.#sourceNameToTableDef = Object.create(null);
     for (const table of Object.values(remoteModule.tables)) {
       this.#rowDeserializers[table.sourceName] = ProductType.makeDeserializer(
@@ -213,6 +218,15 @@ export class DbConnectionImpl<RemoteModule extends UntypedRemoteModule>
       this.#sourceNameToTableDef[table.sourceName] = table as Values<
         RemoteModule['tables']
       >;
+      const primaryKeyColumn = Object.entries(table.columns).find(
+        ([, column]) => column.columnMetadata.isPrimaryKey
+      );
+      this.#rowIdMetadata[table.sourceName] = primaryKeyColumn
+        ? {
+            primaryKeyColName: primaryKeyColumn[0],
+            primaryKeyColType: primaryKeyColumn[1].typeBuilder.algebraicType,
+          }
+        : {};
     }
 
     this.#reducerArgsSerializers = Object.create(null);
@@ -302,8 +316,6 @@ export class DbConnectionImpl<RemoteModule extends UntypedRemoteModule>
   #makeReducers(def: RemoteModule): ReducersView<RemoteModule> {
     const out: Record<string, unknown> = {};
 
-    const writer = new BinaryWriter(1024);
-
     for (const reducer of def.reducers) {
       const reducerName = reducer.name;
       const key = reducer.accessorName;
@@ -312,6 +324,7 @@ export class DbConnectionImpl<RemoteModule extends UntypedRemoteModule>
         this.#reducerArgsSerializers[reducerName];
 
       (out as any)[key] = (params: InferTypeOfRow<typeof reducer.params>) => {
+        const writer = this.#reducerArgsEncoder;
         writer.clear();
         serializeArgs(writer, params);
         const argsBuffer = writer.getBuffer();
@@ -428,20 +441,13 @@ export class DbConnectionImpl<RemoteModule extends UntypedRemoteModule>
     const rows: Operation[] = [];
 
     const deserializeRow = this.#rowDeserializers[tableName];
-    const table = this.#sourceNameToTableDef[tableName];
-    // TODO: performance
-    const columnsArray = Object.entries(table.columns);
-    const primaryKeyColumnEntry = columnsArray.find(
-      col => col[1].columnMetadata.isPrimaryKey
-    );
+    const { primaryKeyColName, primaryKeyColType } =
+      this.#rowIdMetadata[tableName];
     let previousOffset = 0;
     while (reader.remaining > 0) {
       const row = deserializeRow(reader);
       let rowId: ComparablePrimitive | undefined = undefined;
-      if (primaryKeyColumnEntry !== undefined) {
-        const primaryKeyColName = primaryKeyColumnEntry[0];
-        const primaryKeyColType =
-          primaryKeyColumnEntry[1].typeBuilder.algebraicType;
+      if (primaryKeyColName !== undefined && primaryKeyColType !== undefined) {
         rowId = AlgebraicType.intoMapKey(
           primaryKeyColType,
           row[primaryKeyColName]
@@ -548,6 +554,7 @@ export class DbConnectionImpl<RemoteModule extends UntypedRemoteModule>
     }
   }
 
+  #reducerArgsEncoder = new BinaryWriter(1024);
   #clientMessageEncoder = new BinaryWriter(1024);
   #sendMessage(message: ClientMessage): void {
     const writer = this.#clientMessageEncoder;
@@ -906,7 +913,8 @@ export class DbConnectionImpl<RemoteModule extends UntypedRemoteModule>
     _paramsType: ProductType,
     params: object
   ): Promise<void> {
-    const writer = new BinaryWriter(1024);
+    const writer = this.#reducerArgsEncoder;
+    writer.clear();
     this.#reducerArgsSerializers[reducerName].serialize(writer, params);
     const argsBuffer = writer.getBuffer();
     return this.callReducer(reducerName, argsBuffer, params);
diff --git a/crates/bindings-typescript/src/sdk/table_cache.ts b/crates/bindings-typescript/src/sdk/table_cache.ts
index 17ce4b42548..42645daaecf 100644
--- a/crates/bindings-typescript/src/sdk/table_cache.ts
+++ b/crates/bindings-typescript/src/sdk/table_cache.ts
@@ -66,6 +66,7 @@ export class TableCacheImpl<
   TableName extends TableNamesOf<RemoteModule>,
 > implements ClientTableCoreImplementable<RemoteModule, TableName>
 {
+  private readonly hasPrimaryKey: boolean;
   private rows: Map<
     ComparablePrimitive,
     [RowType<TableDefForTableName<RemoteModule, TableName>>, number]
@@ -83,6 +84,9 @@ export class TableCacheImpl<
     this.tableDef = tableDef;
     this.rows = new Map();
     this.emitter = new EventEmitter();
+    this.hasPrimaryKey = Object.values(this.tableDef.columns).some(
+      col => col.columnMetadata.isPrimaryKey === true
+    );
     // Build index views from the resolved runtime index metadata.
     //
     // We intentionally use `resolvedIndexes` rather than `indexes`:
@@ -281,11 +285,7 @@ export class TableCacheImpl<
       return pendingCallbacks;
     }
 
-    // TODO: performance
-    const hasPrimaryKey = Object.values(this.tableDef.columns).some(
-      col => col.columnMetadata.isPrimaryKey === true
-    );
-    if (hasPrimaryKey) {
+    if (this.hasPrimaryKey) {
       const insertMap = new Map<
         ComparablePrimitive,
         [