Add workflow for running sqlsmith

sqlsmith is a random SQL query generator and very useful for finding
bugs in our implementation as it tests complex queries and thereby
hits codepaths and interactions between different features not tested
in our normal regression checks.

.github/workflows/sqlsmith.yaml

@@ -0,0 +1,109 @@
+name: SQLsmith
+on:
+  schedule:
+    # run daily 20:00 on master branch
+    - cron: '0 2 * * *'
+jobs:
+  regress:
+    name: SQLsmith PG${{ matrix.pg }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: ["ubuntu-20.04"]
+        pg: ["14.2"]
+        cc: ["gcc"]
+        build_type: ["Debug"]
+      fail-fast: false
+    env:
+      PG_SRC_DIR: pgbuild
+      PG_INSTALL_DIR: postgresql
+
+    steps:
+    - name: Install Linux Dependencies
+      run: |
+        sudo apt-get update
+        sudo apt-get install flex bison systemd-coredump gdb clang-9 llvm-9 llvm-9-dev llvm-9-tools build-essential autoconf autoconf-archive libpqxx-dev libboost-regex-dev libsqlite3-dev
+
+    # this workflow depends on the cached postgres build from the main regression
+    # workflow since that workflow runs daily there should always be a cache hit
+    - name: Cache PostgreSQL ${{ matrix.pg }}
+      id: cache-postgresql
+      uses: actions/cache@v2
+      with:
+        path: ~/${{ env.PG_SRC_DIR }}
+        key: ${{ matrix.os }}-postgresql-${{ matrix.pg }}-${{ matrix.cc }}-${{ matrix.build_type }}
+
+    # we abort on cache miss otherwise we would have to reproduce most variables
+    # of the main regression build matrix in this workflow
+    - name: Abort on cache miss
+      if: steps.cache-postgresql.outputs.cache-hit != 'true'
+      run: false
+
+    - name: Install PostgreSQL ${{ matrix.pg }} ${{ matrix.build_type }}
+      run: |
+        make -C ~/$PG_SRC_DIR install
+        make -C ~/$PG_SRC_DIR/contrib/postgres_fdw install
+
+    - name: Checkout TimescaleDB
+      uses: actions/checkout@v2
+
+    - name: Build TimescaleDB
+      run: |
+        ./bootstrap -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} -DPG_SOURCE_DIR=~/$PG_SRC_DIR -DPG_PATH=~/$PG_INSTALL_DIR ${{ matrix.tsdb_build_args }}
+        make -C build
+        make -C build install
+
+    - name: Checkout sqlsmith
+      uses: actions/checkout@v2
+      with:
+        repository: 'timescale/sqlsmith'
+        path: 'sqlsmith'
+        ref: 'timescaledb'
+
+    - name: Build SQLsmith
+      run: |
+        cd sqlsmith
+        autoreconf -i
+        ./configure
+        make
+
+    - name: Setup test environment
+      run: |
+        mkdir ~/pgdata
+        ~/$PG_INSTALL_DIR/bin/initdb ~/pgdata
+        ~/$PG_INSTALL_DIR/bin/pg_ctl -D ~/pgdata start -o "-cshared_preload_libraries=timescaledb" -o "-cmax_connections=200" -o "-cmax_prepared_transactions=100"
+        psql -h /tmp postgres -c 'CREATE DATABASE smith;'
+        psql -h /tmp smith -c 'CREATE EXTENSION timescaledb;'
+        psql -h /tmp smith -c '\i ${{ github.workspace }}/tsl/test/shared/sql/include/shared_setup.sql'
+
+    # we run these in a loop to reinitialize the random number generator
+    # 10 times 10000 queries seems to take roughly 40 minutes in CI
+    - name: Run SQLsmith
+      run: |
+        cd sqlsmith
+        for i in `seq 1 10`; do ./sqlsmith --seed=$((16#$(openssl rand -hex 3))) --exclude-catalog --target="host=/tmp dbname=smith" --max-queries=10000; done
+
+    - name: Check for coredumps
+      if: always()
+      id: collectlogs
+      run: |
+        # wait for in progress coredumps
+        sleep 10
+        if coredumpctl list; then
+          echo "::set-output name=coredumps::true"
+          false
+        fi
+
+    - name: Stack trace
+      if: always() && steps.collectlogs.outputs.coredumps == 'true'
+      run: |
+        echo "bt full" | sudo coredumpctl gdb
+        ./scripts/bundle_coredumps.sh
+        false
+
+    - name: Upload Coredumps
+      if: always() && steps.collectlogs.outputs.coredumps == 'true'
+      uses: actions/upload-artifact@v2
+      with:
+        name: Coredumps sqlsmith ${{ matrix.os }} PG${{ matrix.pg }}
+        path: coredumps