mirror of
https://github.com/matrix-org/dendrite
synced 2024-09-06 11:15:34 +02:00
966 lines
36 KiB
Go
966 lines
36 KiB
Go
// Copyright 2017 Vector Creations 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 state provides functions for reading state from the database.
|
|
// The functions for writing state to the database are the input package.
|
|
package state
|
|
|
|
import (
|
|
"context"
|
|
"fmt"
|
|
"sort"
|
|
"time"
|
|
|
|
"github.com/matrix-org/dendrite/roomserver/types"
|
|
"github.com/matrix-org/gomatrixserverlib"
|
|
"github.com/matrix-org/util"
|
|
"github.com/prometheus/client_golang/prometheus"
|
|
)
|
|
|
|
// A RoomStateDatabase has the storage APIs needed to load state from the database
|
|
type RoomStateDatabase interface {
|
|
// Store the room state at an event in the database
|
|
AddState(
|
|
ctx context.Context,
|
|
roomNID types.RoomNID,
|
|
stateBlockNIDs []types.StateBlockNID,
|
|
state []types.StateEntry,
|
|
) (types.StateSnapshotNID, error)
|
|
// Look up the state of a room at each event for a list of string event IDs.
|
|
// Returns an error if there is an error talking to the database
|
|
// Returns a types.MissingEventError if the room state for the event IDs aren't in the database
|
|
StateAtEventIDs(ctx context.Context, eventIDs []string) ([]types.StateAtEvent, error)
|
|
// Look up the numeric IDs for a list of string event types.
|
|
// Returns a map from string event type to numeric ID for the event type.
|
|
EventTypeNIDs(ctx context.Context, eventTypes []string) (map[string]types.EventTypeNID, error)
|
|
// Look up the numeric IDs for a list of string event state keys.
|
|
// Returns a map from string state key to numeric ID for the state key.
|
|
EventStateKeyNIDs(ctx context.Context, eventStateKeys []string) (map[string]types.EventStateKeyNID, error)
|
|
// Look up the numeric state data IDs for each numeric state snapshot ID
|
|
// The returned slice is sorted by numeric state snapshot ID.
|
|
StateBlockNIDs(ctx context.Context, stateNIDs []types.StateSnapshotNID) ([]types.StateBlockNIDList, error)
|
|
// Look up the state data for each numeric state data ID
|
|
// The returned slice is sorted by numeric state data ID.
|
|
StateEntries(ctx context.Context, stateBlockNIDs []types.StateBlockNID) ([]types.StateEntryList, error)
|
|
// Look up the state data for the state key tuples for each numeric state block ID
|
|
// This is used to fetch a subset of the room state at a snapshot.
|
|
// If a block doesn't contain any of the requested tuples then it can be discarded from the result.
|
|
// The returned slice is sorted by numeric state block ID.
|
|
StateEntriesForTuples(
|
|
ctx context.Context,
|
|
stateBlockNIDs []types.StateBlockNID,
|
|
stateKeyTuples []types.StateKeyTuple,
|
|
) ([]types.StateEntryList, error)
|
|
// Look up the Events for a list of numeric event IDs.
|
|
// Returns a sorted list of events.
|
|
Events(ctx context.Context, eventNIDs []types.EventNID) ([]types.Event, error)
|
|
// Look up snapshot NID for an event ID string
|
|
SnapshotNIDFromEventID(ctx context.Context, eventID string) (types.StateSnapshotNID, error)
|
|
}
|
|
|
|
// LoadStateAtSnapshot loads the full state of a room at a particular snapshot.
|
|
// This is typically the state before an event or the current state of a room.
|
|
// Returns a sorted list of state entries or an error if there was a problem talking to the database.
|
|
func LoadStateAtSnapshot(
|
|
ctx context.Context, db RoomStateDatabase, stateNID types.StateSnapshotNID,
|
|
) ([]types.StateEntry, error) {
|
|
stateBlockNIDLists, err := db.StateBlockNIDs(ctx, []types.StateSnapshotNID{stateNID})
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
// We've asked for exactly one snapshot from the db so we should have exactly one entry in the result.
|
|
stateBlockNIDList := stateBlockNIDLists[0]
|
|
|
|
stateEntryLists, err := db.StateEntries(ctx, stateBlockNIDList.StateBlockNIDs)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
stateEntriesMap := stateEntryListMap(stateEntryLists)
|
|
|
|
// Combine all the state entries for this snapshot.
|
|
// The order of state block NIDs in the list tells us the order to combine them in.
|
|
var fullState []types.StateEntry
|
|
for _, stateBlockNID := range stateBlockNIDList.StateBlockNIDs {
|
|
entries, ok := stateEntriesMap.lookup(stateBlockNID)
|
|
if !ok {
|
|
// This should only get hit if the database is corrupt.
|
|
// It should be impossible for an event to reference a NID that doesn't exist
|
|
panic(fmt.Errorf("Corrupt DB: Missing state block numeric ID %d", stateBlockNID))
|
|
}
|
|
fullState = append(fullState, entries...)
|
|
}
|
|
|
|
// Stable sort so that the most recent entry for each state key stays
|
|
// remains later in the list than the older entries for the same state key.
|
|
sort.Stable(stateEntryByStateKeySorter(fullState))
|
|
// Unique returns the last entry and hence the most recent entry for each state key.
|
|
fullState = fullState[:util.Unique(stateEntryByStateKeySorter(fullState))]
|
|
return fullState, nil
|
|
}
|
|
|
|
// LoadStateAtEvent loads the full state of a room at a particular event.
|
|
func LoadStateAtEvent(
|
|
ctx context.Context, db RoomStateDatabase, eventID string,
|
|
) ([]types.StateEntry, error) {
|
|
snapshotNID, err := db.SnapshotNIDFromEventID(ctx, eventID)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
stateEntries, err := LoadStateAtSnapshot(ctx, db, snapshotNID)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return stateEntries, nil
|
|
}
|
|
|
|
// LoadCombinedStateAfterEvents loads a snapshot of the state after each of the events
|
|
// and combines those snapshots together into a single list.
|
|
func LoadCombinedStateAfterEvents(
|
|
ctx context.Context, db RoomStateDatabase, prevStates []types.StateAtEvent,
|
|
) ([]types.StateEntry, error) {
|
|
stateNIDs := make([]types.StateSnapshotNID, len(prevStates))
|
|
for i, state := range prevStates {
|
|
stateNIDs[i] = state.BeforeStateSnapshotNID
|
|
}
|
|
// Fetch the state snapshots for the state before the each prev event from the database.
|
|
// Deduplicate the IDs before passing them to the database.
|
|
// There could be duplicates because the events could be state events where
|
|
// the snapshot of the room state before them was the same.
|
|
stateBlockNIDLists, err := db.StateBlockNIDs(ctx, uniqueStateSnapshotNIDs(stateNIDs))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
var stateBlockNIDs []types.StateBlockNID
|
|
for _, list := range stateBlockNIDLists {
|
|
stateBlockNIDs = append(stateBlockNIDs, list.StateBlockNIDs...)
|
|
}
|
|
// Fetch the state entries that will be combined to create the snapshots.
|
|
// Deduplicate the IDs before passing them to the database.
|
|
// There could be duplicates because a block of state entries could be reused by
|
|
// multiple snapshots.
|
|
stateEntryLists, err := db.StateEntries(ctx, uniqueStateBlockNIDs(stateBlockNIDs))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
stateBlockNIDsMap := stateBlockNIDListMap(stateBlockNIDLists)
|
|
stateEntriesMap := stateEntryListMap(stateEntryLists)
|
|
|
|
// Combine the entries from all the snapshots of state after each prev event into a single list.
|
|
var combined []types.StateEntry
|
|
for _, prevState := range prevStates {
|
|
// Grab the list of state data NIDs for this snapshot.
|
|
stateBlockNIDs, ok := stateBlockNIDsMap.lookup(prevState.BeforeStateSnapshotNID)
|
|
if !ok {
|
|
// This should only get hit if the database is corrupt.
|
|
// It should be impossible for an event to reference a NID that doesn't exist
|
|
panic(fmt.Errorf("Corrupt DB: Missing state snapshot numeric ID %d", prevState.BeforeStateSnapshotNID))
|
|
}
|
|
|
|
// Combine all the state entries for this snapshot.
|
|
// The order of state block NIDs in the list tells us the order to combine them in.
|
|
var fullState []types.StateEntry
|
|
for _, stateBlockNID := range stateBlockNIDs {
|
|
entries, ok := stateEntriesMap.lookup(stateBlockNID)
|
|
if !ok {
|
|
// This should only get hit if the database is corrupt.
|
|
// It should be impossible for an event to reference a NID that doesn't exist
|
|
panic(fmt.Errorf("Corrupt DB: Missing state block numeric ID %d", stateBlockNID))
|
|
}
|
|
fullState = append(fullState, entries...)
|
|
}
|
|
if prevState.IsStateEvent() {
|
|
// If the prev event was a state event then add an entry for the event itself
|
|
// so that we get the state after the event rather than the state before.
|
|
fullState = append(fullState, prevState.StateEntry)
|
|
}
|
|
|
|
// Stable sort so that the most recent entry for each state key stays
|
|
// remains later in the list than the older entries for the same state key.
|
|
sort.Stable(stateEntryByStateKeySorter(fullState))
|
|
// Unique returns the last entry and hence the most recent entry for each state key.
|
|
fullState = fullState[:util.Unique(stateEntryByStateKeySorter(fullState))]
|
|
// Add the full state for this StateSnapshotNID.
|
|
combined = append(combined, fullState...)
|
|
}
|
|
return combined, nil
|
|
}
|
|
|
|
// DifferenceBetweeenStateSnapshots works out which state entries have been added and removed between two snapshots.
|
|
func DifferenceBetweeenStateSnapshots(
|
|
ctx context.Context, db RoomStateDatabase, oldStateNID, newStateNID types.StateSnapshotNID,
|
|
) (removed, added []types.StateEntry, err error) {
|
|
if oldStateNID == newStateNID {
|
|
// If the snapshot NIDs are the same then nothing has changed
|
|
return nil, nil, nil
|
|
}
|
|
|
|
var oldEntries []types.StateEntry
|
|
var newEntries []types.StateEntry
|
|
if oldStateNID != 0 {
|
|
oldEntries, err = LoadStateAtSnapshot(ctx, db, oldStateNID)
|
|
if err != nil {
|
|
return nil, nil, err
|
|
}
|
|
}
|
|
if newStateNID != 0 {
|
|
newEntries, err = LoadStateAtSnapshot(ctx, db, newStateNID)
|
|
if err != nil {
|
|
return nil, nil, err
|
|
}
|
|
}
|
|
|
|
var oldI int
|
|
var newI int
|
|
for {
|
|
switch {
|
|
case oldI == len(oldEntries):
|
|
// We've reached the end of the old entries.
|
|
// The rest of the new list must have been newly added.
|
|
added = append(added, newEntries[newI:]...)
|
|
return
|
|
case newI == len(newEntries):
|
|
// We've reached the end of the new entries.
|
|
// The rest of the old list must be have been removed.
|
|
removed = append(removed, oldEntries[oldI:]...)
|
|
return
|
|
case oldEntries[oldI] == newEntries[newI]:
|
|
// The entry is in both lists so skip over it.
|
|
oldI++
|
|
newI++
|
|
case oldEntries[oldI].LessThan(newEntries[newI]):
|
|
// The lists are sorted so the old entry being less than the new entry means that it only appears in the old list.
|
|
removed = append(removed, oldEntries[oldI])
|
|
oldI++
|
|
default:
|
|
// Reaching the default case implies that the new entry is less than the old entry.
|
|
// Since the lists are sorted this means that it only appears in the new list.
|
|
added = append(added, newEntries[newI])
|
|
newI++
|
|
}
|
|
}
|
|
}
|
|
|
|
// LoadStateAtSnapshotForStringTuples loads the state for a list of event type and state key pairs at a snapshot.
|
|
// This is used when we only want to load a subset of the room state at a snapshot.
|
|
// If there is no entry for a given event type and state key pair then it will be discarded.
|
|
// This is typically the state before an event or the current state of a room.
|
|
// Returns a sorted list of state entries or an error if there was a problem talking to the database.
|
|
func LoadStateAtSnapshotForStringTuples(
|
|
ctx context.Context,
|
|
db RoomStateDatabase,
|
|
stateNID types.StateSnapshotNID,
|
|
stateKeyTuples []gomatrixserverlib.StateKeyTuple,
|
|
) ([]types.StateEntry, error) {
|
|
numericTuples, err := stringTuplesToNumericTuples(ctx, db, stateKeyTuples)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return loadStateAtSnapshotForNumericTuples(ctx, db, stateNID, numericTuples)
|
|
}
|
|
|
|
// stringTuplesToNumericTuples converts the string state key tuples into numeric IDs
|
|
// If there isn't a numeric ID for either the event type or the event state key then the tuple is discarded.
|
|
// Returns an error if there was a problem talking to the database.
|
|
func stringTuplesToNumericTuples(
|
|
ctx context.Context,
|
|
db RoomStateDatabase,
|
|
stringTuples []gomatrixserverlib.StateKeyTuple,
|
|
) ([]types.StateKeyTuple, error) {
|
|
eventTypes := make([]string, len(stringTuples))
|
|
stateKeys := make([]string, len(stringTuples))
|
|
for i := range stringTuples {
|
|
eventTypes[i] = stringTuples[i].EventType
|
|
stateKeys[i] = stringTuples[i].StateKey
|
|
}
|
|
eventTypes = util.UniqueStrings(eventTypes)
|
|
eventTypeMap, err := db.EventTypeNIDs(ctx, eventTypes)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
stateKeys = util.UniqueStrings(stateKeys)
|
|
stateKeyMap, err := db.EventStateKeyNIDs(ctx, stateKeys)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
var result []types.StateKeyTuple
|
|
for _, stringTuple := range stringTuples {
|
|
var numericTuple types.StateKeyTuple
|
|
var ok1, ok2 bool
|
|
numericTuple.EventTypeNID, ok1 = eventTypeMap[stringTuple.EventType]
|
|
numericTuple.EventStateKeyNID, ok2 = stateKeyMap[stringTuple.StateKey]
|
|
// Discard the tuple if there wasn't a numeric ID for either the event type or the state key.
|
|
if ok1 && ok2 {
|
|
result = append(result, numericTuple)
|
|
}
|
|
}
|
|
|
|
return result, nil
|
|
}
|
|
|
|
// loadStateAtSnapshotForNumericTuples loads the state for a list of event type and state key pairs at a snapshot.
|
|
// This is used when we only want to load a subset of the room state at a snapshot.
|
|
// If there is no entry for a given event type and state key pair then it will be discarded.
|
|
// This is typically the state before an event or the current state of a room.
|
|
// Returns a sorted list of state entries or an error if there was a problem talking to the database.
|
|
func loadStateAtSnapshotForNumericTuples(
|
|
ctx context.Context,
|
|
db RoomStateDatabase,
|
|
stateNID types.StateSnapshotNID,
|
|
stateKeyTuples []types.StateKeyTuple,
|
|
) ([]types.StateEntry, error) {
|
|
stateBlockNIDLists, err := db.StateBlockNIDs(ctx, []types.StateSnapshotNID{stateNID})
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
// We've asked for exactly one snapshot from the db so we should have exactly one entry in the result.
|
|
stateBlockNIDList := stateBlockNIDLists[0]
|
|
|
|
stateEntryLists, err := db.StateEntriesForTuples(
|
|
ctx, stateBlockNIDList.StateBlockNIDs, stateKeyTuples,
|
|
)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
stateEntriesMap := stateEntryListMap(stateEntryLists)
|
|
|
|
// Combine all the state entries for this snapshot.
|
|
// The order of state block NIDs in the list tells us the order to combine them in.
|
|
var fullState []types.StateEntry
|
|
for _, stateBlockNID := range stateBlockNIDList.StateBlockNIDs {
|
|
entries, ok := stateEntriesMap.lookup(stateBlockNID)
|
|
if !ok {
|
|
// If the block is missing from the map it means that none of its entries matched a requested tuple.
|
|
// This can happen if the block doesn't contain an update for one of the requested tuples.
|
|
// If none of the requested tuples are in the block then it can be safely skipped.
|
|
continue
|
|
}
|
|
fullState = append(fullState, entries...)
|
|
}
|
|
|
|
// Stable sort so that the most recent entry for each state key stays
|
|
// remains later in the list than the older entries for the same state key.
|
|
sort.Stable(stateEntryByStateKeySorter(fullState))
|
|
// Unique returns the last entry and hence the most recent entry for each state key.
|
|
fullState = fullState[:util.Unique(stateEntryByStateKeySorter(fullState))]
|
|
return fullState, nil
|
|
}
|
|
|
|
// LoadStateAfterEventsForStringTuples loads the state for a list of event type
|
|
// and state key pairs after list of events.
|
|
// This is used when we only want to load a subset of the room state after a list of events.
|
|
// If there is no entry for a given event type and state key pair then it will be discarded.
|
|
// This is typically the state before an event.
|
|
// Returns a sorted list of state entries or an error if there was a problem talking to the database.
|
|
func LoadStateAfterEventsForStringTuples(
|
|
ctx context.Context,
|
|
db RoomStateDatabase,
|
|
prevStates []types.StateAtEvent,
|
|
stateKeyTuples []gomatrixserverlib.StateKeyTuple,
|
|
) ([]types.StateEntry, error) {
|
|
numericTuples, err := stringTuplesToNumericTuples(ctx, db, stateKeyTuples)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return loadStateAfterEventsForNumericTuples(ctx, db, prevStates, numericTuples)
|
|
}
|
|
|
|
func loadStateAfterEventsForNumericTuples(
|
|
ctx context.Context,
|
|
db RoomStateDatabase,
|
|
prevStates []types.StateAtEvent,
|
|
stateKeyTuples []types.StateKeyTuple,
|
|
) ([]types.StateEntry, error) {
|
|
if len(prevStates) == 1 {
|
|
// Fast path for a single event.
|
|
prevState := prevStates[0]
|
|
result, err := loadStateAtSnapshotForNumericTuples(
|
|
ctx, db, prevState.BeforeStateSnapshotNID, stateKeyTuples,
|
|
)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if prevState.IsStateEvent() {
|
|
// The result is current the state before the requested event.
|
|
// We want the state after the requested event.
|
|
// If the requested event was a state event then we need to
|
|
// update that key in the result.
|
|
// If the requested event wasn't a state event then the state after
|
|
// it is the same as the state before it.
|
|
for i := range result {
|
|
if result[i].StateKeyTuple == prevState.StateKeyTuple {
|
|
result[i] = prevState.StateEntry
|
|
}
|
|
}
|
|
}
|
|
return result, nil
|
|
}
|
|
|
|
// Slow path for more that one event.
|
|
// Load the entire state so that we can do conflict resolution if we need to.
|
|
// TODO: The are some optimistations we could do here:
|
|
// 1) We only need to do conflict resolution if there is a conflict in the
|
|
// requested tuples so we might try loading just those tuples and then
|
|
// checking for conflicts.
|
|
// 2) When there is a conflict we still only need to load the state
|
|
// needed to do conflict resolution which would save us having to load
|
|
// the full state.
|
|
|
|
// TODO: Add metrics for this as it could take a long time for big rooms
|
|
// with large conflicts.
|
|
fullState, _, _, err := calculateStateAfterManyEvents(ctx, db, prevStates)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Sort the full state so we can use it as a map.
|
|
sort.Sort(stateEntrySorter(fullState))
|
|
|
|
// Filter the full state down to the required tuples.
|
|
var result []types.StateEntry
|
|
for _, tuple := range stateKeyTuples {
|
|
eventNID, ok := stateEntryMap(fullState).lookup(tuple)
|
|
if ok {
|
|
result = append(result, types.StateEntry{
|
|
StateKeyTuple: tuple,
|
|
EventNID: eventNID,
|
|
})
|
|
}
|
|
}
|
|
sort.Sort(stateEntrySorter(result))
|
|
return result, nil
|
|
}
|
|
|
|
var calculateStateDurations = prometheus.NewSummaryVec(
|
|
prometheus.SummaryOpts{
|
|
Namespace: "dendrite",
|
|
Subsystem: "roomserver",
|
|
Name: "calculate_state_duration_microseconds",
|
|
Help: "How long it takes to calculate the state after a list of events",
|
|
},
|
|
// Takes two labels:
|
|
// algorithm:
|
|
// The algorithm used to calculate the state or the step it failed on if it failed.
|
|
// Labels starting with "_" are used to indicate when the algorithm fails halfway.
|
|
// outcome:
|
|
// Whether the state was successfully calculated.
|
|
//
|
|
// The possible values for algorithm are:
|
|
// empty_state -> The list of events was empty so the state is empty.
|
|
// no_change -> The state hasn't changed.
|
|
// single_delta -> There was a single event added to the state in a way that can be encoded as a single delta
|
|
// full_state_no_conflicts -> We created a new copy of the full room state, but didn't enounter any conflicts
|
|
// while doing so.
|
|
// full_state_with_conflicts -> We created a new copy of the full room state and had to resolve conflicts to do so.
|
|
// _load_state_block_nids -> Failed loading the state block nids for a single previous state.
|
|
// _load_combined_state -> Failed to load the combined state.
|
|
// _resolve_conflicts -> Failed to resolve conflicts.
|
|
[]string{"algorithm", "outcome"},
|
|
)
|
|
|
|
var calculateStatePrevEventLength = prometheus.NewSummaryVec(
|
|
prometheus.SummaryOpts{
|
|
Namespace: "dendrite",
|
|
Subsystem: "roomserver",
|
|
Name: "calculate_state_prev_event_length",
|
|
Help: "The length of the list of events to calculate the state after",
|
|
},
|
|
[]string{"algorithm", "outcome"},
|
|
)
|
|
|
|
var calculateStateFullStateLength = prometheus.NewSummaryVec(
|
|
prometheus.SummaryOpts{
|
|
Namespace: "dendrite",
|
|
Subsystem: "roomserver",
|
|
Name: "calculate_state_full_state_length",
|
|
Help: "The length of the full room state.",
|
|
},
|
|
[]string{"algorithm", "outcome"},
|
|
)
|
|
|
|
var calculateStateConflictLength = prometheus.NewSummaryVec(
|
|
prometheus.SummaryOpts{
|
|
Namespace: "dendrite",
|
|
Subsystem: "roomserver",
|
|
Name: "calculate_state_conflict_state_length",
|
|
Help: "The length of the conflicted room state.",
|
|
},
|
|
[]string{"algorithm", "outcome"},
|
|
)
|
|
|
|
type calculateStateMetrics struct {
|
|
algorithm string
|
|
startTime time.Time
|
|
prevEventLength int
|
|
fullStateLength int
|
|
conflictLength int
|
|
}
|
|
|
|
func (c *calculateStateMetrics) stop(stateNID types.StateSnapshotNID, err error) (types.StateSnapshotNID, error) {
|
|
var outcome string
|
|
if err == nil {
|
|
outcome = "success"
|
|
} else {
|
|
outcome = "failure"
|
|
}
|
|
endTime := time.Now()
|
|
calculateStateDurations.WithLabelValues(c.algorithm, outcome).Observe(
|
|
float64(endTime.Sub(c.startTime).Nanoseconds()) / 1000.,
|
|
)
|
|
calculateStatePrevEventLength.WithLabelValues(c.algorithm, outcome).Observe(
|
|
float64(c.prevEventLength),
|
|
)
|
|
calculateStateFullStateLength.WithLabelValues(c.algorithm, outcome).Observe(
|
|
float64(c.fullStateLength),
|
|
)
|
|
calculateStateConflictLength.WithLabelValues(c.algorithm, outcome).Observe(
|
|
float64(c.conflictLength),
|
|
)
|
|
return stateNID, err
|
|
}
|
|
|
|
func init() {
|
|
prometheus.MustRegister(
|
|
calculateStateDurations, calculateStatePrevEventLength,
|
|
calculateStateFullStateLength, calculateStateConflictLength,
|
|
)
|
|
}
|
|
|
|
// CalculateAndStoreStateBeforeEvent calculates a snapshot of the state of a room before an event.
|
|
// Stores the snapshot of the state in the database.
|
|
// Returns a numeric ID for the snapshot of the state before the event.
|
|
func CalculateAndStoreStateBeforeEvent(
|
|
ctx context.Context,
|
|
db RoomStateDatabase,
|
|
event gomatrixserverlib.Event,
|
|
roomNID types.RoomNID,
|
|
) (types.StateSnapshotNID, error) {
|
|
// Load the state at the prev events.
|
|
prevEventRefs := event.PrevEvents()
|
|
prevEventIDs := make([]string, len(prevEventRefs))
|
|
for i := range prevEventRefs {
|
|
prevEventIDs[i] = prevEventRefs[i].EventID
|
|
}
|
|
|
|
prevStates, err := db.StateAtEventIDs(ctx, prevEventIDs)
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
// The state before this event will be the state after the events that came before it.
|
|
return CalculateAndStoreStateAfterEvents(ctx, db, roomNID, prevStates)
|
|
}
|
|
|
|
// CalculateAndStoreStateAfterEvents finds the room state after the given events.
|
|
// Stores the resulting state in the database and returns a numeric ID for that snapshot.
|
|
func CalculateAndStoreStateAfterEvents(
|
|
ctx context.Context,
|
|
db RoomStateDatabase,
|
|
roomNID types.RoomNID,
|
|
prevStates []types.StateAtEvent,
|
|
) (types.StateSnapshotNID, error) {
|
|
metrics := calculateStateMetrics{startTime: time.Now(), prevEventLength: len(prevStates)}
|
|
|
|
if len(prevStates) == 0 {
|
|
// 2) There weren't any prev_events for this event so the state is
|
|
// empty.
|
|
metrics.algorithm = "empty_state"
|
|
return metrics.stop(db.AddState(ctx, roomNID, nil, nil))
|
|
}
|
|
|
|
if len(prevStates) == 1 {
|
|
prevState := prevStates[0]
|
|
if prevState.EventStateKeyNID == 0 {
|
|
// 3) None of the previous events were state events and they all
|
|
// have the same state, so this event has exactly the same state
|
|
// as the previous events.
|
|
// This should be the common case.
|
|
metrics.algorithm = "no_change"
|
|
return metrics.stop(prevState.BeforeStateSnapshotNID, nil)
|
|
}
|
|
// The previous event was a state event so we need to store a copy
|
|
// of the previous state updated with that event.
|
|
stateBlockNIDLists, err := db.StateBlockNIDs(
|
|
ctx, []types.StateSnapshotNID{prevState.BeforeStateSnapshotNID},
|
|
)
|
|
if err != nil {
|
|
metrics.algorithm = "_load_state_blocks"
|
|
return metrics.stop(0, err)
|
|
}
|
|
stateBlockNIDs := stateBlockNIDLists[0].StateBlockNIDs
|
|
if len(stateBlockNIDs) < maxStateBlockNIDs {
|
|
// 4) The number of state data blocks is small enough that we can just
|
|
// add the state event as a block of size one to the end of the blocks.
|
|
metrics.algorithm = "single_delta"
|
|
return metrics.stop(db.AddState(
|
|
ctx, roomNID, stateBlockNIDs, []types.StateEntry{prevState.StateEntry},
|
|
))
|
|
}
|
|
// If there are too many deltas then we need to calculate the full state
|
|
// So fall through to calculateAndStoreStateAfterManyEvents
|
|
}
|
|
|
|
return calculateAndStoreStateAfterManyEvents(ctx, db, roomNID, prevStates, metrics)
|
|
}
|
|
|
|
// maxStateBlockNIDs is the maximum number of state data blocks to use to encode a snapshot of room state.
|
|
// Increasing this number means that we can encode more of the state changes as simple deltas which means that
|
|
// we need fewer entries in the state data table. However making this number bigger will increase the size of
|
|
// the rows in the state table itself and will require more index lookups when retrieving a snapshot.
|
|
// TODO: Tune this to get the right balance between size and lookup performance.
|
|
const maxStateBlockNIDs = 64
|
|
|
|
// calculateAndStoreStateAfterManyEvents finds the room state after the given events.
|
|
// This handles the slow path of calculateAndStoreStateAfterEvents for when there is more than one event.
|
|
// Stores the resulting state and returns a numeric ID for the snapshot.
|
|
func calculateAndStoreStateAfterManyEvents(
|
|
ctx context.Context,
|
|
db RoomStateDatabase,
|
|
roomNID types.RoomNID,
|
|
prevStates []types.StateAtEvent,
|
|
metrics calculateStateMetrics,
|
|
) (types.StateSnapshotNID, error) {
|
|
|
|
state, algorithm, conflictLength, err :=
|
|
calculateStateAfterManyEvents(ctx, db, prevStates)
|
|
metrics.algorithm = algorithm
|
|
if err != nil {
|
|
return metrics.stop(0, err)
|
|
}
|
|
|
|
// TODO: Check if we can encode the new state as a delta against the
|
|
// previous state.
|
|
metrics.conflictLength = conflictLength
|
|
metrics.fullStateLength = len(state)
|
|
return metrics.stop(db.AddState(ctx, roomNID, nil, state))
|
|
}
|
|
|
|
func calculateStateAfterManyEvents(
|
|
ctx context.Context, db RoomStateDatabase, prevStates []types.StateAtEvent,
|
|
) (state []types.StateEntry, algorithm string, conflictLength int, err error) {
|
|
var combined []types.StateEntry
|
|
// Conflict resolution.
|
|
// First stage: load the state after each of the prev events.
|
|
combined, err = LoadCombinedStateAfterEvents(ctx, db, prevStates)
|
|
if err != nil {
|
|
algorithm = "_load_combined_state"
|
|
return
|
|
}
|
|
|
|
// Collect all the entries with the same type and key together.
|
|
// We don't care about the order here because the conflict resolution
|
|
// algorithm doesn't depend on the order of the prev events.
|
|
// Remove duplicate entires.
|
|
combined = combined[:util.SortAndUnique(stateEntrySorter(combined))]
|
|
|
|
// Find the conflicts
|
|
conflicts := findDuplicateStateKeys(combined)
|
|
|
|
if len(conflicts) > 0 {
|
|
conflictLength = len(conflicts)
|
|
|
|
// 5) There are conflicting state events, for each conflict workout
|
|
// what the appropriate state event is.
|
|
|
|
// Work out which entries aren't conflicted.
|
|
var notConflicted []types.StateEntry
|
|
for _, entry := range combined {
|
|
if _, ok := stateEntryMap(conflicts).lookup(entry.StateKeyTuple); !ok {
|
|
notConflicted = append(notConflicted, entry)
|
|
}
|
|
}
|
|
|
|
var resolved []types.StateEntry
|
|
resolved, err = resolveConflicts(ctx, db, notConflicted, conflicts)
|
|
if err != nil {
|
|
algorithm = "_resolve_conflicts"
|
|
return
|
|
}
|
|
algorithm = "full_state_with_conflicts"
|
|
state = resolved
|
|
} else {
|
|
algorithm = "full_state_no_conflicts"
|
|
// 6) There weren't any conflicts
|
|
state = combined
|
|
}
|
|
return
|
|
}
|
|
|
|
// resolveConflicts resolves a list of conflicted state entries. It takes two lists.
|
|
// The first is a list of all state entries that are not conflicted.
|
|
// The second is a list of all state entries that are conflicted
|
|
// A state entry is conflicted when there is more than one numeric event ID for the same state key tuple.
|
|
// Returns a list that combines the entries without conflicts with the result of state resolution for the entries with conflicts.
|
|
// The returned list is sorted by state key tuple.
|
|
// Returns an error if there was a problem talking to the database.
|
|
func resolveConflicts(
|
|
ctx context.Context,
|
|
db RoomStateDatabase,
|
|
notConflicted, conflicted []types.StateEntry,
|
|
) ([]types.StateEntry, error) {
|
|
|
|
// Load the conflicted events
|
|
conflictedEvents, eventIDMap, err := loadStateEvents(ctx, db, conflicted)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Work out which auth events we need to load.
|
|
needed := gomatrixserverlib.StateNeededForAuth(conflictedEvents)
|
|
|
|
// Find the numeric IDs for the necessary state keys.
|
|
var neededStateKeys []string
|
|
neededStateKeys = append(neededStateKeys, needed.Member...)
|
|
neededStateKeys = append(neededStateKeys, needed.ThirdPartyInvite...)
|
|
stateKeyNIDMap, err := db.EventStateKeyNIDs(ctx, neededStateKeys)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Load the necessary auth events.
|
|
tuplesNeeded := stateKeyTuplesNeeded(stateKeyNIDMap, needed)
|
|
var authEntries []types.StateEntry
|
|
for _, tuple := range tuplesNeeded {
|
|
if eventNID, ok := stateEntryMap(notConflicted).lookup(tuple); ok {
|
|
authEntries = append(authEntries, types.StateEntry{
|
|
StateKeyTuple: tuple,
|
|
EventNID: eventNID,
|
|
})
|
|
}
|
|
}
|
|
authEvents, _, err := loadStateEvents(ctx, db, authEntries)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Resolve the conflicts.
|
|
resolvedEvents := gomatrixserverlib.ResolveStateConflicts(conflictedEvents, authEvents)
|
|
|
|
// Map from the full events back to numeric state entries.
|
|
for _, resolvedEvent := range resolvedEvents {
|
|
entry, ok := eventIDMap[resolvedEvent.EventID()]
|
|
if !ok {
|
|
panic(fmt.Errorf("Missing state entry for event ID %q", resolvedEvent.EventID()))
|
|
}
|
|
notConflicted = append(notConflicted, entry)
|
|
}
|
|
|
|
// Sort the result so it can be searched.
|
|
sort.Sort(stateEntrySorter(notConflicted))
|
|
return notConflicted, nil
|
|
}
|
|
|
|
// stateKeyTuplesNeeded works out which numeric state key tuples we need to authenticate some events.
|
|
func stateKeyTuplesNeeded(stateKeyNIDMap map[string]types.EventStateKeyNID, stateNeeded gomatrixserverlib.StateNeeded) []types.StateKeyTuple {
|
|
var keyTuples []types.StateKeyTuple
|
|
if stateNeeded.Create {
|
|
keyTuples = append(keyTuples, types.StateKeyTuple{
|
|
EventTypeNID: types.MRoomCreateNID,
|
|
EventStateKeyNID: types.EmptyStateKeyNID,
|
|
})
|
|
}
|
|
if stateNeeded.PowerLevels {
|
|
keyTuples = append(keyTuples, types.StateKeyTuple{
|
|
EventTypeNID: types.MRoomPowerLevelsNID,
|
|
EventStateKeyNID: types.EmptyStateKeyNID,
|
|
})
|
|
}
|
|
if stateNeeded.JoinRules {
|
|
keyTuples = append(keyTuples, types.StateKeyTuple{
|
|
EventTypeNID: types.MRoomJoinRulesNID,
|
|
EventStateKeyNID: types.EmptyStateKeyNID,
|
|
})
|
|
}
|
|
for _, member := range stateNeeded.Member {
|
|
stateKeyNID, ok := stateKeyNIDMap[member]
|
|
if ok {
|
|
keyTuples = append(keyTuples, types.StateKeyTuple{
|
|
EventTypeNID: types.MRoomMemberNID,
|
|
EventStateKeyNID: stateKeyNID,
|
|
})
|
|
}
|
|
}
|
|
for _, token := range stateNeeded.ThirdPartyInvite {
|
|
stateKeyNID, ok := stateKeyNIDMap[token]
|
|
if ok {
|
|
keyTuples = append(keyTuples, types.StateKeyTuple{
|
|
EventTypeNID: types.MRoomThirdPartyInviteNID,
|
|
EventStateKeyNID: stateKeyNID,
|
|
})
|
|
}
|
|
}
|
|
return keyTuples
|
|
}
|
|
|
|
// loadStateEvents loads the matrix events for a list of state entries.
|
|
// Returns a list of state events in no particular order and a map from string event ID back to state entry.
|
|
// The map can be used to recover which numeric state entry a given event is for.
|
|
// Returns an error if there was a problem talking to the database.
|
|
func loadStateEvents(
|
|
ctx context.Context, db RoomStateDatabase, entries []types.StateEntry,
|
|
) ([]gomatrixserverlib.Event, map[string]types.StateEntry, error) {
|
|
eventNIDs := make([]types.EventNID, len(entries))
|
|
for i := range entries {
|
|
eventNIDs[i] = entries[i].EventNID
|
|
}
|
|
events, err := db.Events(ctx, eventNIDs)
|
|
if err != nil {
|
|
return nil, nil, err
|
|
}
|
|
eventIDMap := map[string]types.StateEntry{}
|
|
result := make([]gomatrixserverlib.Event, len(entries))
|
|
for i := range entries {
|
|
event, ok := eventMap(events).lookup(entries[i].EventNID)
|
|
if !ok {
|
|
panic(fmt.Errorf("Corrupt DB: Missing event numeric ID %d", entries[i].EventNID))
|
|
}
|
|
result[i] = event.Event
|
|
eventIDMap[event.Event.EventID()] = entries[i]
|
|
}
|
|
return result, eventIDMap, nil
|
|
}
|
|
|
|
// findDuplicateStateKeys finds the state entries where the state key tuple appears more than once in a sorted list.
|
|
// Returns a sorted list of those state entries.
|
|
func findDuplicateStateKeys(a []types.StateEntry) []types.StateEntry {
|
|
var result []types.StateEntry
|
|
// j is the starting index of a block of entries with the same state key tuple.
|
|
j := 0
|
|
for i := 1; i < len(a); i++ {
|
|
// Check if the state key tuple matches the start of the block
|
|
if a[j].StateKeyTuple != a[i].StateKeyTuple {
|
|
// If the state key tuple is different then we've reached the end of a block of duplicates.
|
|
// Check if the size of the block is bigger than one.
|
|
// If the size is one then there was only a single entry with that state key tuple so we don't add it to the result
|
|
if j+1 != i {
|
|
// Add the block to the result.
|
|
result = append(result, a[j:i]...)
|
|
}
|
|
// Start a new block for the next state key tuple.
|
|
j = i
|
|
}
|
|
}
|
|
// Check if the last block with the same state key tuple had more than one event in it.
|
|
if j+1 != len(a) {
|
|
result = append(result, a[j:]...)
|
|
}
|
|
return result
|
|
}
|
|
|
|
type stateEntrySorter []types.StateEntry
|
|
|
|
func (s stateEntrySorter) Len() int { return len(s) }
|
|
func (s stateEntrySorter) Less(i, j int) bool { return s[i].LessThan(s[j]) }
|
|
func (s stateEntrySorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
|
|
|
|
type stateBlockNIDListMap []types.StateBlockNIDList
|
|
|
|
func (m stateBlockNIDListMap) lookup(stateNID types.StateSnapshotNID) (stateBlockNIDs []types.StateBlockNID, ok bool) {
|
|
list := []types.StateBlockNIDList(m)
|
|
i := sort.Search(len(list), func(i int) bool {
|
|
return list[i].StateSnapshotNID >= stateNID
|
|
})
|
|
if i < len(list) && list[i].StateSnapshotNID == stateNID {
|
|
ok = true
|
|
stateBlockNIDs = list[i].StateBlockNIDs
|
|
}
|
|
return
|
|
}
|
|
|
|
type stateEntryListMap []types.StateEntryList
|
|
|
|
func (m stateEntryListMap) lookup(stateBlockNID types.StateBlockNID) (stateEntries []types.StateEntry, ok bool) {
|
|
list := []types.StateEntryList(m)
|
|
i := sort.Search(len(list), func(i int) bool {
|
|
return list[i].StateBlockNID >= stateBlockNID
|
|
})
|
|
if i < len(list) && list[i].StateBlockNID == stateBlockNID {
|
|
ok = true
|
|
stateEntries = list[i].StateEntries
|
|
}
|
|
return
|
|
}
|
|
|
|
type stateEntryByStateKeySorter []types.StateEntry
|
|
|
|
func (s stateEntryByStateKeySorter) Len() int { return len(s) }
|
|
func (s stateEntryByStateKeySorter) Less(i, j int) bool {
|
|
return s[i].StateKeyTuple.LessThan(s[j].StateKeyTuple)
|
|
}
|
|
func (s stateEntryByStateKeySorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
|
|
|
|
type stateNIDSorter []types.StateSnapshotNID
|
|
|
|
func (s stateNIDSorter) Len() int { return len(s) }
|
|
func (s stateNIDSorter) Less(i, j int) bool { return s[i] < s[j] }
|
|
func (s stateNIDSorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
|
|
|
|
func uniqueStateSnapshotNIDs(nids []types.StateSnapshotNID) []types.StateSnapshotNID {
|
|
return nids[:util.SortAndUnique(stateNIDSorter(nids))]
|
|
}
|
|
|
|
type stateBlockNIDSorter []types.StateBlockNID
|
|
|
|
func (s stateBlockNIDSorter) Len() int { return len(s) }
|
|
func (s stateBlockNIDSorter) Less(i, j int) bool { return s[i] < s[j] }
|
|
func (s stateBlockNIDSorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
|
|
|
|
func uniqueStateBlockNIDs(nids []types.StateBlockNID) []types.StateBlockNID {
|
|
return nids[:util.SortAndUnique(stateBlockNIDSorter(nids))]
|
|
}
|
|
|
|
// Map from event type, state key tuple to numeric event ID.
|
|
// Implemented using binary search on a sorted array.
|
|
type stateEntryMap []types.StateEntry
|
|
|
|
// lookup an entry in the event map.
|
|
func (m stateEntryMap) lookup(stateKey types.StateKeyTuple) (eventNID types.EventNID, ok bool) {
|
|
// Since the list is sorted we can implement this using binary search.
|
|
// This is faster than using a hash map.
|
|
// We don't have to worry about pathological cases because the keys are fixed
|
|
// size and are controlled by us.
|
|
list := []types.StateEntry(m)
|
|
i := sort.Search(len(list), func(i int) bool {
|
|
return !list[i].StateKeyTuple.LessThan(stateKey)
|
|
})
|
|
if i < len(list) && list[i].StateKeyTuple == stateKey {
|
|
ok = true
|
|
eventNID = list[i].EventNID
|
|
}
|
|
return
|
|
}
|
|
|
|
// Map from numeric event ID to event.
|
|
// Implemented using binary search on a sorted array.
|
|
type eventMap []types.Event
|
|
|
|
// lookup an entry in the event map.
|
|
func (m eventMap) lookup(eventNID types.EventNID) (event *types.Event, ok bool) {
|
|
// Since the list is sorted we can implement this using binary search.
|
|
// This is faster than using a hash map.
|
|
// We don't have to worry about pathological cases because the keys are fixed
|
|
// size are controlled by us.
|
|
list := []types.Event(m)
|
|
i := sort.Search(len(list), func(i int) bool {
|
|
return list[i].EventNID >= eventNID
|
|
})
|
|
if i < len(list) && list[i].EventNID == eventNID {
|
|
ok = true
|
|
event = &list[i]
|
|
}
|
|
return
|
|
}
|