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Get the SQL working, and make it more idempotent (#17) 

* Get the SQL working, and make it more idempotent
main
Mark Haines 2017-02-22 16:51:10 +00:00 committed by GitHub
parent c96d3eec0c
commit a9b296c522
6 changed files with 66 additions and 32 deletions
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15
src/github.com/matrix-org/dendrite/roomserver/input/latest_events.go
View File

@ -58,15 +58,23 @@ func doUpdateLatestEvents(
}
// Check if this event references any of the latest events in the room.
var alreadyInLatest bool
var newLatest []types.StateAtEventAndReference
for _, l := range oldLatest {
keep := true
for _, prevEvent := range prevEvents {
if l.EventID == prevEvent.EventID && bytes.Compare(l.EventSHA256, prevEvent.EventSHA256) == 0 {
// This event can be removed from the latest events cause we've found an event that references it.
// (If an event is referenced by another event then it can't be one of the latest events in the room
// because we have an event that comes after it)
continue
keep = false
break
}
}
if l.EventNID == stateAtEvent.EventNID {
alreadyInLatest = true
}
if keep {
// Keep the event in the latest events.
newLatest = append(newLatest, l)
}
@ -79,8 +87,9 @@ func doUpdateLatestEvents(
return err
}
if !alreadyReferenced {
// This event is not referenced by any of the events in the room.
if !alreadyReferenced && !alreadyInLatest {
// This event is not referenced by any of the events in the room
// and the event is not already in the latest events.
// Add it to the latest events
newLatest = append(newLatest, types.StateAtEventAndReference{
StateAtEvent: stateAtEvent,

3
src/github.com/matrix-org/dendrite/roomserver/storage/event_state_keys_table.go
View File

@ -31,8 +31,7 @@ INSERT INTO event_state_keys (event_state_key_nid, event_state_key) VALUES
const insertEventStateKeyNIDSQL = "" +
"INSERT INTO event_state_keys (event_state_key) VALUES ($1)" +
" ON CONFLICT ON CONSTRAINT event_state_key_unique" +
" DO UPDATE SET event_state_key = $1" +
" RETURNING (event_state_key_nid)"
" DO NOTHING RETURNING (event_state_key_nid)"
const selectEventStateKeyNIDSQL = "" +
"SELECT event_state_key_nid FROM event_state_keys WHERE event_state_key = $1"

14
src/github.com/matrix-org/dendrite/roomserver/storage/event_types_table.go
View File

@ -50,14 +50,18 @@ INSERT INTO event_types (event_type_nid, event_type) VALUES
// In that case the ID will be assigned using the next value from the sequence.
// We use `RETURNING` to tell postgres to return the assigned ID.
// But it's possible that the type was added in a query that raced with us.
// This will result in a conflict on the event_type_unique constraint.
// We peform a update that does nothing rather that doing nothing at all because
// postgres won't return anything unless we touch a row in the table.
// This will result in a conflict on the event_type_unique constraint, in this
// case we do nothing. Postgresql won't return a row in that case so we rely on
// the caller catching the sql.ErrNoRows error and running a select to get the row.
// We could get postgresql to return the row on a conflict by updating the row
// but it doesn't seem like a good idea to modify the rows just to make postgresql
// return it. Modifying the rows will cause postgres to assign a new tuple for the
// row even though the data doesn't change resulting in unncesssary modifications
// to the indexes.
const insertEventTypeNIDSQL = "" +
"INSERT INTO event_types (event_type) VALUES ($1)" +
" ON CONFLICT ON CONSTRAINT event_type_unique" +
" DO UPDATE SET event_type = $1" +
" RETURNING (event_type_nid)"
" DO NOTHING RETURNING (event_type_nid)"
const selectEventTypeNIDSQL = "" +
"SELECT event_type_nid FROM event_types WHERE event_type = $1"

20
src/github.com/matrix-org/dendrite/roomserver/storage/events_table.go
View File

@ -47,9 +47,12 @@ const insertEventSQL = "" +
"INSERT INTO events (room_nid, event_type_nid, event_state_key_nid, event_id, reference_sha256, auth_event_nids)" +
" VALUES ($1, $2, $3, $4, $5, $6)" +
" ON CONFLICT ON CONSTRAINT event_id_unique" +
" DO UPDATE SET event_id = $1" +
" DO NOTHING" +
" RETURNING event_nid, state_snapshot_nid"
const selectEventSQL = "" +
"SELECT event_nid, state_snapshot_nid FROM events WHERE event_id = $1"
// Bulk lookup of events by string ID.
// Sort by the numeric IDs for event type and state key.
// This means we can use binary search to lookup entries by type and state key.
@ -71,6 +74,7 @@ const bulkSelectStateAtEventAndReferenceSQL = "" +
type eventStatements struct {
insertEventStmt *sql.Stmt
selectEventStmt *sql.Stmt
bulkSelectStateEventByIDStmt *sql.Stmt
bulkSelectStateAtEventByIDStmt *sql.Stmt
updateEventStateStmt *sql.Stmt
@ -85,6 +89,9 @@ func (s *eventStatements) prepare(db *sql.DB) (err error) {
if s.insertEventStmt, err = db.Prepare(insertEventSQL); err != nil {
return
}
if s.selectEventStmt, err = db.Prepare(selectEventSQL); err != nil {
return
}
if s.bulkSelectStateEventByIDStmt, err = db.Prepare(bulkSelectStateEventByIDSQL); err != nil {
return
}
@ -119,6 +126,13 @@ func (s *eventStatements) insertEvent(
return types.EventNID(eventNID), types.StateSnapshotNID(stateNID), err
}
func (s *eventStatements) selectEvent(eventID string) (types.EventNID, types.StateSnapshotNID, error) {
var eventNID int64
var stateNID int64
err := s.selectEventStmt.QueryRow(eventID).Scan(&eventNID, &stateNID)
return types.EventNID(eventNID), types.StateSnapshotNID(stateNID), err
}
func (s *eventStatements) bulkSelectStateEventByID(eventIDs []string) ([]types.StateEntry, error) {
rows, err := s.bulkSelectStateEventByIDStmt.Query(pq.StringArray(eventIDs))
if err != nil {
@ -134,9 +148,9 @@ func (s *eventStatements) bulkSelectStateEventByID(eventIDs []string) ([]types.S
for ; rows.Next(); i++ {
result := &results[i]
if err = rows.Scan(
&result.EventNID,
&result.EventTypeNID,
&result.EventStateKeyNID,
&result.EventNID,
); err != nil {
return nil, err
}
@ -163,9 +177,9 @@ func (s *eventStatements) bulkSelectStateAtEventByID(eventIDs []string) ([]types
for ; rows.Next(); i++ {
result := &results[i]
if err = rows.Scan(
&result.EventNID,
&result.EventTypeNID,
&result.EventStateKeyNID,
&result.EventNID,
&result.BeforeStateSnapshotNID,
); err != nil {
return nil, err

5
src/github.com/matrix-org/dendrite/roomserver/storage/rooms_table.go
View File

@ -16,7 +16,7 @@ CREATE TABLE IF NOT EXISTS rooms (
-- The most recent events in the room that aren't referenced by another event.
-- This list may empty if the server hasn't joined the room yet.
-- (The server will be in that state while it stores the events for the initial state of the room)
latest_event_nids BIGINT[] NOT NULL
latest_event_nids BIGINT[] NOT NULL DEFAULT '{}'::BIGINT[]
);
`
@ -24,8 +24,7 @@ CREATE TABLE IF NOT EXISTS rooms (
const insertRoomNIDSQL = "" +
"INSERT INTO rooms (room_id) VALUES ($1)" +
" ON CONFLICT ON CONSTRAINT room_id_unique" +
" DO UPDATE SET room_id = $1" +
" RETURNING (room_nid)"
" DO NOTHING RETURNING (room_nid)"
const selectRoomNIDSQL = "" +
"SELECT room_nid FROM rooms WHERE room_id = $1"

41
src/github.com/matrix-org/dendrite/roomserver/storage/storage.go
View File

@ -73,7 +73,13 @@ func (d *Database) StoreEvent(event gomatrixserverlib.Event, authEventNIDs []typ
event.EventReference().EventSHA256,
authEventNIDs,
); err != nil {
return 0, types.StateAtEvent{}, err
if err == sql.ErrNoRows {
// We've already inserted the event so select the numeric event ID
eventNID, stateNID, err = d.statements.selectEvent(event.EventID())
}
if err != nil {
return 0, types.StateAtEvent{}, err
}
}
if err = d.statements.insertEventJSON(eventNID, event.JSON()); err != nil {
@ -97,12 +103,13 @@ func (d *Database) assignRoomNID(roomID string) (types.RoomNID, error) {
roomNID, err := d.statements.selectRoomNID(roomID)
if err == sql.ErrNoRows {
// We don't have a numeric ID so insert one into the database.
return d.statements.insertRoomNID(roomID)
roomNID, err = d.statements.insertRoomNID(roomID)
if err == sql.ErrNoRows {
// We raced with another insert so run the select again.
roomNID, err = d.statements.selectRoomNID(roomID)
}
}
if err != nil {
return 0, err
}
return roomNID, nil
return roomNID, err
}
func (d *Database) assignEventTypeNID(eventType string) (types.EventTypeNID, error) {
@ -110,12 +117,13 @@ func (d *Database) assignEventTypeNID(eventType string) (types.EventTypeNID, err
eventTypeNID, err := d.statements.selectEventTypeNID(eventType)
if err == sql.ErrNoRows {
// We don't have a numeric ID so insert one into the database.
return d.statements.insertEventTypeNID(eventType)
eventTypeNID, err = d.statements.insertEventTypeNID(eventType)
if err == sql.ErrNoRows {
// We raced with another insert so run the select again.
eventTypeNID, err = d.statements.selectEventTypeNID(eventType)
}
}
if err != nil {
return 0, err
}
return eventTypeNID, nil
return eventTypeNID, err
}
func (d *Database) assignStateKeyNID(eventStateKey string) (types.EventStateKeyNID, error) {
@ -123,12 +131,13 @@ func (d *Database) assignStateKeyNID(eventStateKey string) (types.EventStateKeyN
eventStateKeyNID, err := d.statements.selectEventStateKeyNID(eventStateKey)
if err == sql.ErrNoRows {
// We don't have a numeric ID so insert one into the database.
return d.statements.insertEventStateKeyNID(eventStateKey)
eventStateKeyNID, err = d.statements.insertEventStateKeyNID(eventStateKey)
if err == sql.ErrNoRows {
// We raced with another insert so run the select again.
eventStateKeyNID, err = d.statements.selectEventStateKeyNID(eventStateKey)
}
}
if err != nil {
return 0, err
}
return eventStateKeyNID, nil
return eventStateKeyNID, err
}
// StateEntriesForEventIDs implements input.EventDatabase