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dendrite/roomserver/storage/sqlite3/state_snapshot_table.go
kegsay ed04eed441
Fix sqlite migration issues (#1960)
* Do not store 'null' in the database for empty JSON arrays

This can cause issues, though it should be noted that the majority
of the time this will marshal/unmarshal just fine, see
https://play.golang.org/p/Doe2NZUgv7Q

* bugfix: sqlite migration should handle create events as having no 'before' snapshot

The state snapshot for any given event in the roomserver represents the state _before_
the event. For the create event, this is nothing, so the state snapshot nid should be 0.

In some cases this wasn't happening, resulting in a nice mix of possible options including:
 - A state snapshot without any state blocks `[]` or `null`.
 - A state snapshot with a single state block with a single event, the create event, causing
   a circular loop. This is incorrect as it represents the state before the event, not after.

* Add state key check
2021-08-04 17:08:17 +01:00

142 lines
4.8 KiB
Go

// Copyright 2017-2018 New Vector Ltd
// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package sqlite3
import (
"context"
"database/sql"
"encoding/json"
"fmt"
"strings"
"github.com/matrix-org/dendrite/internal"
"github.com/matrix-org/dendrite/internal/sqlutil"
"github.com/matrix-org/dendrite/roomserver/storage/tables"
"github.com/matrix-org/dendrite/roomserver/types"
"github.com/matrix-org/util"
)
const stateSnapshotSchema = `
CREATE TABLE IF NOT EXISTS roomserver_state_snapshots (
-- The state snapshot NID that identifies this snapshot.
state_snapshot_nid INTEGER PRIMARY KEY AUTOINCREMENT,
-- The hash of the state snapshot, which is used to enforce uniqueness. The hash is
-- generated in Dendrite and passed through to the database, as a btree index over
-- this column is cheap and fits within the maximum index size.
state_snapshot_hash BLOB UNIQUE,
-- The room NID that the snapshot belongs to.
room_nid INTEGER NOT NULL,
-- The state blocks contained within this snapshot, encoded as JSON.
state_block_nids TEXT NOT NULL DEFAULT '[]'
);
`
// Insert a new state snapshot. If we conflict on the hash column then
// we must perform an update so that the RETURNING statement returns the
// ID of the row that we conflicted with, so that we can then refer to
// the original snapshot.
const insertStateSQL = `
INSERT INTO roomserver_state_snapshots (state_snapshot_hash, room_nid, state_block_nids)
VALUES ($1, $2, $3)
ON CONFLICT (state_snapshot_hash) DO UPDATE SET room_nid=$2
RETURNING state_snapshot_nid
`
// Bulk state data NID lookup.
// Sorting by state_snapshot_nid means we can use binary search over the result
// to lookup the state data NIDs for a state snapshot NID.
const bulkSelectStateBlockNIDsSQL = "" +
"SELECT state_snapshot_nid, state_block_nids FROM roomserver_state_snapshots" +
" WHERE state_snapshot_nid IN ($1) ORDER BY state_snapshot_nid ASC"
type stateSnapshotStatements struct {
db *sql.DB
insertStateStmt *sql.Stmt
bulkSelectStateBlockNIDsStmt *sql.Stmt
}
func createStateSnapshotTable(db *sql.DB) error {
_, err := db.Exec(stateSnapshotSchema)
return err
}
func prepareStateSnapshotTable(db *sql.DB) (tables.StateSnapshot, error) {
s := &stateSnapshotStatements{
db: db,
}
return s, sqlutil.StatementList{
{&s.insertStateStmt, insertStateSQL},
{&s.bulkSelectStateBlockNIDsStmt, bulkSelectStateBlockNIDsSQL},
}.Prepare(db)
}
func (s *stateSnapshotStatements) InsertState(
ctx context.Context, txn *sql.Tx, roomNID types.RoomNID, stateBlockNIDs types.StateBlockNIDs,
) (stateNID types.StateSnapshotNID, err error) {
if stateBlockNIDs == nil {
stateBlockNIDs = []types.StateBlockNID{} // zero slice to not store 'null' in the DB
}
stateBlockNIDs = stateBlockNIDs[:util.SortAndUnique(stateBlockNIDs)]
stateBlockNIDsJSON, err := json.Marshal(stateBlockNIDs)
if err != nil {
return
}
insertStmt := sqlutil.TxStmt(txn, s.insertStateStmt)
var id int64
err = insertStmt.QueryRowContext(ctx, stateBlockNIDs.Hash(), int64(roomNID), string(stateBlockNIDsJSON)).Scan(&id)
if err != nil {
return 0, err
}
stateNID = types.StateSnapshotNID(id)
return
}
func (s *stateSnapshotStatements) BulkSelectStateBlockNIDs(
ctx context.Context, stateNIDs []types.StateSnapshotNID,
) ([]types.StateBlockNIDList, error) {
nids := make([]interface{}, len(stateNIDs))
for k, v := range stateNIDs {
nids[k] = v
}
selectOrig := strings.Replace(bulkSelectStateBlockNIDsSQL, "($1)", sqlutil.QueryVariadic(len(nids)), 1)
selectStmt, err := s.db.Prepare(selectOrig)
if err != nil {
return nil, err
}
rows, err := selectStmt.QueryContext(ctx, nids...)
if err != nil {
return nil, err
}
defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectStateBlockNIDs: rows.close() failed")
results := make([]types.StateBlockNIDList, len(stateNIDs))
i := 0
for ; rows.Next(); i++ {
result := &results[i]
var stateBlockNIDsJSON string
if err := rows.Scan(&result.StateSnapshotNID, &stateBlockNIDsJSON); err != nil {
return nil, err
}
if err := json.Unmarshal([]byte(stateBlockNIDsJSON), &result.StateBlockNIDs); err != nil {
return nil, err
}
}
if i != len(stateNIDs) {
return nil, fmt.Errorf("storage: state NIDs missing from the database (%d != %d)", i, len(stateNIDs))
}
return results, nil
}