From 53b94f135abfc1d67e8cefe6ab1f1550afe11d8d Mon Sep 17 00:00:00 2001 From: Felix Lange Date: Thu, 4 Nov 2021 17:44:35 +0100 Subject: [PATCH] rpc: linear time batch response matching (#23856) This avoids quadratic time complexity in the lookup of the batch element corresponding to an RPC response. Unfortunately, the new approach requires additional memory for the mapping from ID to index. Fixes #22805 --- rpc/client.go | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/rpc/client.go b/rpc/client.go index edd9ecf1b6..e43760c22c 100644 --- a/rpc/client.go +++ b/rpc/client.go @@ -17,7 +17,6 @@ package rpc import ( - "bytes" "context" "encoding/json" "errors" @@ -360,7 +359,10 @@ func (c *Client) BatchCall(b []BatchElem) error { // // Note that batch calls may not be executed atomically on the server side. func (c *Client) BatchCallContext(ctx context.Context, b []BatchElem) error { - msgs := make([]*jsonrpcMessage, len(b)) + var ( + msgs = make([]*jsonrpcMessage, len(b)) + byID = make(map[string]int, len(b)) + ) op := &requestOp{ ids: make([]json.RawMessage, len(b)), resp: make(chan *jsonrpcMessage, len(b)), @@ -372,6 +374,7 @@ func (c *Client) BatchCallContext(ctx context.Context, b []BatchElem) error { } msgs[i] = msg op.ids[i] = msg.ID + byID[string(msg.ID)] = i } var err error @@ -391,13 +394,7 @@ func (c *Client) BatchCallContext(ctx context.Context, b []BatchElem) error { // Find the element corresponding to this response. // The element is guaranteed to be present because dispatch // only sends valid IDs to our channel. - var elem *BatchElem - for i := range msgs { - if bytes.Equal(msgs[i].ID, resp.ID) { - elem = &b[i] - break - } - } + elem := &b[byID[string(resp.ID)]] if resp.Error != nil { elem.Error = resp.Error continue