diff options
Diffstat (limited to 'syncapi/storage/postgres/backward_extremities_table.go')
| -rw-r--r-- | syncapi/storage/postgres/backward_extremities_table.go | 124 |
1 files changed, 0 insertions, 124 deletions
diff --git a/syncapi/storage/postgres/backward_extremities_table.go b/syncapi/storage/postgres/backward_extremities_table.go deleted file mode 100644 index cb362964..00000000 --- a/syncapi/storage/postgres/backward_extremities_table.go +++ /dev/null @@ -1,124 +0,0 @@ -// Copyright 2018 New Vector Ltd -// -// 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 postgres - -import ( - "context" - "database/sql" - - "github.com/matrix-org/dendrite/common" -) - -// The purpose of this table is to keep track of backwards extremities for a room. -// Backwards extremities are the earliest (DAG-wise) known events which we have -// the entire event JSON. These event IDs are used in federation requests to fetch -// even earlier events. -// -// We persist the previous event IDs as well, one per row, so when we do fetch even -// earlier events we can simply delete rows which referenced it. Consider the graph: -// A -// | Event C has 1 prev_event ID: A. -// B C -// |___| Event D has 2 prev_event IDs: B and C. -// | -// D -// The earliest known event we have is D, so this table has 2 rows. -// A backfill request gives us C but not B. We delete rows where prev_event=C. This -// still means that D is a backwards extremity as we do not have event B. However, event -// C is *also* a backwards extremity at this point as we do not have event A. Later, -// when we fetch event B, we delete rows where prev_event=B. This then removes D as -// a backwards extremity because there are no more rows with event_id=B. -const backwardExtremitiesSchema = ` --- Stores output room events received from the roomserver. -CREATE TABLE IF NOT EXISTS syncapi_backward_extremities ( - -- The 'room_id' key for the event. - room_id TEXT NOT NULL, - -- The event ID for the last known event. This is the backwards extremity. - event_id TEXT NOT NULL, - -- The prev_events for the last known event. This is used to update extremities. - prev_event_id TEXT NOT NULL, - - PRIMARY KEY(room_id, event_id, prev_event_id) -); -` - -const insertBackwardExtremitySQL = "" + - "INSERT INTO syncapi_backward_extremities (room_id, event_id, prev_event_id)" + - " VALUES ($1, $2, $3)" + - " ON CONFLICT DO NOTHING" - -const selectBackwardExtremitiesForRoomSQL = "" + - "SELECT DISTINCT event_id FROM syncapi_backward_extremities WHERE room_id = $1" - -const deleteBackwardExtremitySQL = "" + - "DELETE FROM syncapi_backward_extremities WHERE room_id = $1 AND prev_event_id = $2" - -type backwardExtremitiesStatements struct { - insertBackwardExtremityStmt *sql.Stmt - selectBackwardExtremitiesForRoomStmt *sql.Stmt - deleteBackwardExtremityStmt *sql.Stmt -} - -func (s *backwardExtremitiesStatements) prepare(db *sql.DB) (err error) { - _, err = db.Exec(backwardExtremitiesSchema) - if err != nil { - return - } - if s.insertBackwardExtremityStmt, err = db.Prepare(insertBackwardExtremitySQL); err != nil { - return - } - if s.selectBackwardExtremitiesForRoomStmt, err = db.Prepare(selectBackwardExtremitiesForRoomSQL); err != nil { - return - } - if s.deleteBackwardExtremityStmt, err = db.Prepare(deleteBackwardExtremitySQL); err != nil { - return - } - return -} - -func (s *backwardExtremitiesStatements) insertsBackwardExtremity( - ctx context.Context, txn *sql.Tx, roomID, eventID string, prevEventID string, -) (err error) { - _, err = txn.Stmt(s.insertBackwardExtremityStmt).ExecContext(ctx, roomID, eventID, prevEventID) - return -} - -func (s *backwardExtremitiesStatements) selectBackwardExtremitiesForRoom( - ctx context.Context, roomID string, -) (eventIDs []string, err error) { - rows, err := s.selectBackwardExtremitiesForRoomStmt.QueryContext(ctx, roomID) - if err != nil { - return - } - defer common.CloseAndLogIfError(ctx, rows, "selectBackwardExtremitiesForRoom: rows.close() failed") - - for rows.Next() { - var eID string - if err = rows.Scan(&eID); err != nil { - return - } - - eventIDs = append(eventIDs, eID) - } - - return eventIDs, rows.Err() -} - -func (s *backwardExtremitiesStatements) deleteBackwardExtremity( - ctx context.Context, txn *sql.Tx, roomID, knownEventID string, -) (err error) { - _, err = txn.Stmt(s.deleteBackwardExtremityStmt).ExecContext(ctx, roomID, knownEventID) - return -} |