migrations: drop packages table

The packages table is no longer used and dropped.

This frees up 827 GB of table space and 78 GB of indexes.

For golang/go#39629

Change-Id: I149707013c3fd39122b55f79976893ca979982cb
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/265243
Trust: Julie Qiu <[email protected]>
Run-TryBot: Julie Qiu <[email protected]>
TryBot-Result: kokoro <[email protected]>
Reviewed-by: Jamal Carvalho <[email protected]>

Author: julieqiu

migrations/000039_drop_packages_table.down.sql

@@ -0,0 +1,44 @@
+-- Copyright 2020 The Go Authors. All rights reserved.
+-- Use of this source code is governed by a BSD-style
+-- license that can be found in the LICENSE file.
+
+BEGIN;
+
+CREATE TABLE packages (
+    path text NOT NULL,
+    module_path text NOT NULL,
+    version text NOT NULL,
+    commit_time timestamp with time zone NOT NULL,
+    name text NOT NULL,
+    synopsis text,
+    license_types text[],
+    license_paths text[],
+    v1_path text NOT NULL,
+    goos text NOT NULL,
+    goarch text NOT NULL,
+    redistributable boolean DEFAULT false NOT NULL,
+    documentation text,
+    tsv_parent_directories tsvector,
+    created_at timestamp with time zone DEFAULT CURRENT_TIMESTAMP NOT NULL,
+    updated_at timestamp with time zone DEFAULT CURRENT_TIMESTAMP NOT NULL,
+    PRIMARY KEY (path, module_path, version),
+    FOREIGN KEY (module_path, version) REFERENCES modules(module_path, version) ON DELETE CASCADE
+);
+COMMENT ON TABLE packages IS
+'TABLE packages contains packages in a specific module version.';
+COMMENT ON COLUMN packages.commit_time IS
+'commit_time is the same as verions.commit_time. It is added here so that we can reduce the number of joins in our queries.';
+COMMENT ON COLUMN packages.tsv_parent_directories IS
+'tsv_parent_directories should always be NOT NULL, but it is populated by a trigger, so it will be initially NULL on insert.';
+
+CREATE INDEX idx_packages_v1_path ON packages (v1_path);
+COMMENT ON INDEX idx_packages_v1_path IS
+'INDEX idx_packages_v1_path is used to get all of the packages in a series.';
+
+CREATE INDEX idx_packages_module_path_text_pattern_ops ON packages (module_path text_pattern_ops);
+COMMENT ON INDEX idx_packages_module_path_text_pattern_ops IS
+'INDEX idx_packages_module_path_text_pattern_ops is used to improve performance of LIKE statements for module_path. It is used to fetch directories matching a given module_path prefix.';
+
+CREATE INDEX idx_packages_path_text_pattern_ops ON packages (path text_pattern_ops);
+
+END;

migrations/000039_drop_packages_table.up.sql

@@ -0,0 +1,9 @@
+-- Copyright 2020 The Go Authors. All rights reserved.
+-- Use of this source code is governed by a BSD-style
+-- license that can be found in the LICENSE file.
+
+BEGIN;
+
+DROP TABLE packages;
+
+END;