From 1f636c445bcbc66b1765bcc3966887adcb14bdbf Mon Sep 17 00:00:00 2001
From: Guo Xiang Tan <tgx_world@hotmail.com>
Date: Thu, 6 Sep 2018 14:29:45 +0800
Subject: [PATCH] PERF: Add fast path to find uploads before resorting to
 `LIKE` query.
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For a normal upload url

Before

```
Warming up --------------------------------------
                       264.000  i/100ms
Calculating -------------------------------------
                          2.754k (± 8.4%) i/s -     13.728k in   5.022066s
```

After

```
Warming up --------------------------------------
                       341.000  i/100ms
Calculating -------------------------------------
                          3.435k (±11.6%) i/s -     17.050k in   5.045676s
```
---
 app/models/upload.rb       | 12 ++++++------
 spec/models/upload_spec.rb |  5 +++--
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/app/models/upload.rb b/app/models/upload.rb
index 4ab07e4ce1b..f035751098f 100644
--- a/app/models/upload.rb
+++ b/app/models/upload.rb
@@ -175,12 +175,12 @@ class Upload < ActiveRecord::Base
     end
 
     return if uri&.path.blank?
-
-    path = uri.path[/(\/original\/\dX\/[\/\.\w]+)/, 1]
-
-    return if path.blank?
-
-    Upload.find_by("url LIKE ?", "%#{path}")
+    data = uri.path.match(/(\/original\/\dX\/[\/\.\w]+\/([a-zA-Z0-9]+)[\.\w]+)/)
+    return if data.blank?
+    sha1 = data[2]
+    upload = nil
+    upload = Upload.find_by(sha1: sha1) if sha1
+    upload || Upload.find_by("url LIKE ?", "%#{data[1]}")
   end
 
   def self.migrate_to_new_scheme(limit = nil)
diff --git a/spec/models/upload_spec.rb b/spec/models/upload_spec.rb
index a52af4a0bd5..b19bcd3d3e3 100644
--- a/spec/models/upload_spec.rb
+++ b/spec/models/upload_spec.rb
@@ -74,8 +74,9 @@ describe Upload do
   end
 
   context ".get_from_url" do
-    let(:url) { "/uploads/default/original/3X/1/0/10f73034616a796dfd70177dc54b6def44c4ba6f.png" }
-    let(:upload) { Fabricate(:upload, url: url) }
+    let(:sha1) { "10f73034616a796dfd70177dc54b6def44c4ba6f" }
+    let(:url) { "/uploads/default/original/3X/1/0/#{sha1}.png" }
+    let(:upload) { Fabricate(:upload, url: url, sha1: sha1) }
 
     it "works when the file has been uploaded" do
       expect(Upload.get_from_url(upload.url)).to eq(upload)