GoToSocial/internal/db/bundb/migrations/20230405130021_status_fave_...

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// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package migrations
import (
"context"
"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
"github.com/uptrace/bun"
)
func init() {
up := func(ctx context.Context, db *bun.DB) error {
// To update fave constraints, we need to migrate faves into a new table.
// See section 7 here: https://www.sqlite.org/lang_altertable.html
return db.RunInTx(ctx, nil, func(ctx context.Context, tx bun.Tx) error {
// Remove any duplicate faves that were created before constraints.
// We need to ensure that we don't just delete all faves that are
// duplicates--we should keep the original, non-duplicate fave.
// So, produced query will look something like this:
//
// DELETE FROM "status_faves"
// WHERE id IN (
// WITH cte AS (
// SELECT
// "id",
// ROW_NUMBER() OVER(
// PARTITION BY "account_id", "status_id"
// ORDER BY "account_id", "status_id"
// ) AS "row_number"
// FROM status_faves
// )
// SELECT "id" FROM cte
// WHERE "row_number" > 1
// )
//
// The above query only deletes status_faves with ids that are
// in the subquery. The subquery selects the IDs of all duplicate
// status faves past the first one, where 'duplicate' means 'has
// the same account id and status id'.
overQ := tx.NewRaw(
"PARTITION BY ?, ? ORDER BY ?, ?",
bun.Ident("account_id"),
bun.Ident("status_id"),
bun.Ident("account_id"),
bun.Ident("status_id"),
)
rowNumberQ := tx.NewRaw(
"SELECT ?, ROW_NUMBER() OVER(?) AS ? FROM status_faves",
bun.Ident("id"),
overQ,
bun.Ident("row_number"),
)
inQ := tx.NewRaw(
"WITH cte AS (?) SELECT ? FROM cte WHERE ? > 1",
rowNumberQ,
bun.Ident("id"),
bun.Ident("row_number"),
)
if _, err := tx.
NewDelete().
Table("status_faves").
Where("id IN (?)", inQ).
Exec(ctx); err != nil {
return err
}
// Create the new faves table.
if _, err := tx.
NewCreateTable().
ModelTableExpr("new_status_faves").
Model(&gtsmodel.StatusFave{}).
Exec(ctx); err != nil {
return err
}
// Specify columns explicitly to
// avoid any Postgres shenanigans.
columns := []string{
"id",
"created_at",
"updated_at",
"account_id",
"target_account_id",
"status_id",
"uri",
}
// Copy remaining faves to the new table.
if _, err := tx.
NewInsert().
Table("new_status_faves").
Table("status_faves").
Column(columns...).
Exec(ctx); err != nil {
return err
}
// Drop the old table.
if _, err := tx.
NewDropTable().
Table("status_faves").
Exec(ctx); err != nil {
return err
}
// Rename new table to old table.
if _, err := tx.
ExecContext(
ctx,
"ALTER TABLE ? RENAME TO ?",
bun.Ident("new_status_faves"),
bun.Ident("status_faves"),
); err != nil {
return err
}
// Add indexes to the new table.
for index, columns := range map[string][]string{
"status_faves_id_idx": {"id"},
"status_faves_account_id_idx": {"account_id"},
"status_faves_status_id_idx": {"status_id"},
} {
if _, err := tx.
NewCreateIndex().
Table("status_faves").
Index(index).
Column(columns...).
Exec(ctx); err != nil {
return err
}
}
return nil
})
}
down := func(ctx context.Context, db *bun.DB) error {
return db.RunInTx(ctx, nil, func(ctx context.Context, tx bun.Tx) error {
return nil
})
}
if err := Migrations.Register(up, down); err != nil {
panic(err)
}
}