Add diesel to the rustc perf test suite

As far as I know diesel is a rather strange workload for rustc.
According to some short measurements most of the time compiling diesel is
spend type checking the crate and resolving trait bounds. I see multiple
reasons for this:

* Diesel builts a complex abstract query dsl for SQL based on rust
generics. All fo this needs to be type checked.
* Diesel generates a ton of trait impls for tuples of various sizes.
There are features to set the supported max size to 16, 32, 64 and 128
tuple elements. As this is a benchmark, I've chosen to set it to 128 to
maximize the number of impls.

As consequence of this diesels compile times are quite sensitive to
changes touching the type system in general and the trait resolution in
detail. Any change that will introduce a behaviour which does not scale
well with the number of available trait impls will likely result in a huge
increase for this benchmark.

Author: weiznich

collector/benchmarks/README.md

@@ -41,6 +41,10 @@ These are real programs that are important in some way, and worth tracking.
 These are real programs that are known to stress the compiler in interesting
 ways.
 
+- **diesel**: A type save SQL query builder. Utilizes the type system to
+  ensure a lot of invariants. Stresses anything related to resolving 
+  trait bounds, by having a lot of trait impls for a large number of different
+  types.
 - **encoding**: Character encoding support. Contains some large tables.
 - **html5ever**: An HTML parser. Stresses macro parsing code significantly.
 - **inflate**: An old implementation of the DEFLATE algorithm. Stresses the

collector/benchmarks/diesel/.editorconfig

@@ -0,0 +1,29 @@
+# EditorConfig helps developers define and maintain consistent
+# coding styles between different editors and IDEs
+# editorconfig.org
+
+root = true
+
+
+[*]
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+indent_style = space
+indent_size = 4
+
+[*.rs]
+indent_style = space
+indent_size = 4
+
+[*.toml]
+indent_style = space
+indent_size = 4
+
+[*.md]
+trim_trailing_whitespace = false
+
+[*.{yml,yaml}]
+indent_style = space
+indent_size = 2

collector/benchmarks/diesel/.env.sample

@@ -0,0 +1,15 @@
+# The database to use when testing against Postgres.
+PG_DATABASE_URL=postgresql://postgres:postgres@localhost:5432/diesel_test
+# The database to use when running the Postgres examples during testing.
+PG_EXAMPLE_DATABASE_URL=postgresql://postgres:postgres@localhost:5432/diesel_example
+
+# The database to use when testing against MySQL.
+MYSQL_DATABASE_URL=mysql://[email protected]:3306/diesel_test
+# The database to use when running the MySQL examples during testing.
+MYSQL_EXAMPLE_DATABASE_URL=mysql://[email protected]:3306/diesel_example
+# A database different from the others above used for certain unit tests.
+# TODO: this is magical, explain what it's there for.
+MYSQL_UNIT_TEST_DATABASE_URL=mysql://[email protected]:3306/diesel_unit_test
+
+# The database to use when testing against SQLite.
+SQLITE_DATABASE_URL=/tmp/diesel_test.sqlite

collector/benchmarks/diesel/.github/FUNDING.yml

@@ -0,0 +1 @@
+github: [sgrif, weiznich]

collector/benchmarks/diesel/.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,51 @@
+<!--
+If you want to report a bug, we added some points below you can fill out. If you want to request a feature, feel free to remove all the irrelevant text. In addition to this [issue tracker](https://github.com/diesel-rs/diesel/issues), you can also talk to Diesel maintainers and users on [Gitter](https://gitter.im/diesel-rs/diesel).
+-->
+
+## Setup
+
+### Versions
+
+- **Rust:**
+- **Diesel:**
+- **Database:**
+- **Operating System**
+
+### Feature Flags
+
+- **diesel:**
+
+## Problem Description
+
+
+### What are you trying to accomplish?
+
+
+### What is the expected output?
+
+
+### What is the actual output?
+
+
+### Are you seeing any additional errors?
+
+
+### Steps to reproduce
+
+<!--
+Please include as much of your codebase as needed to reproduce the error.  If the relevant files are large, please consider linking to a public repository or a [Gist](https://gist.github.com/).
+
+Please post as much of your database schema as necessary. If you are using `infer_schema!`, you can use `diesel print-schema` and post the relevant parts from that.
+-->
+
+## Checklist
+
+- [ ] I have already looked over the [issue tracker](https://github.com/diesel-rs/diesel/issues) for similar issues.
+- [ ] This issue can be reproduced on Rust's stable channel. (Your issue will be
+  closed if this is not the case)
+
+<!--
+Thank you for your submission!  You're helping make Diesel more robust 🎉
+
+We'll try to respond as quickly as possible.
+-->

collector/benchmarks/diesel/.github/workflows/audit.yml

@@ -0,0 +1,16 @@
+name: Security audit
+on:
+  push:
+    paths:
+      - '**/Cargo.toml'
+      - '**/Cargo.lock'
+  schedule:
+    - cron: '0 0 */7 * *'
+jobs:
+  security_audit:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/audit-check@v1
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}

collector/benchmarks/diesel/.github/workflows/benches.yml

@@ -0,0 +1,53 @@
+on:
+  pull_request:
+    types:
+      - labeled
+
+name: Benchmarks
+
+jobs:
+  benchmarks:
+    if: github.event.label.name == 'run-benchmarks'
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        backend: ["postgres", "sqlite", "mysql"]
+    steps:
+      - name: Checkout sources
+        if: steps.bench.outputs.triggered == 'true'
+        uses: actions/checkout@v2
+
+      - name: Install postgres (Linux)
+        if: matrix.backend == 'postgres'
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libpq-dev postgresql
+          echo "host    all             all             127.0.0.1/32            md5" > sudo tee -a /etc/postgresql/10/main/pg_hba.conf
+          sudo service postgresql restart && sleep 3
+          sudo -u postgres psql -c "ALTER USER postgres PASSWORD 'postgres';"
+          sudo service postgresql restart && sleep 3
+          echo '::set-env name=PG_DATABASE_URL::postgres://postgres:postgres@localhost/'
+
+      - name: Install sqlite (Linux)
+        if: matrix.backend == 'sqlite'
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libsqlite3-dev
+          echo '::set-env name=SQLITE_DATABASE_URL::/tmp/test.db'
+
+        
+      - name: Install mysql (Linux)
+        if: matrix.backend == 'mysql'
+        run: |
+          sudo apt-get update
+          sudo apt-get -y install mysql-server libmysqlclient-dev
+          sudo /etc/init.d/mysql start
+          mysql -e "create database diesel_test; create database diesel_unit_test; grant all on \`diesel_%\`.* to 'root'@'localhost';" -uroot -proot
+          echo '::set-env name=MYSQL_DATABASE_URL::mysql://root:root@localhost/diesel_test'
+
+      - name: Run benches
+        uses: jasonwilliams/criterion-compare-action@move_to_actions
+        with:
+          cwd: "diesel_bench"
+          token: ${{ secrets.GITHUB_TOKEN }}
+