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dendrite/roomserver/storage/state_block_table.go
2019-05-21 21:56:55 +01:00

280 lines
10 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 storage
import (
"context"
"database/sql"
"fmt"
"sort"
"github.com/lib/pq"
"github.com/matrix-org/dendrite/roomserver/types"
"github.com/matrix-org/util"
)
const stateDataSchema = `
-- The state data map.
-- Designed to give enough information to run the state resolution algorithm
-- without hitting the database in the common case.
-- TODO: Is it worth replacing the unique btree index with a covering index so
-- that postgres could lookup the state using an index-only scan?
-- The type and state_key are included in the index to make it easier to
-- lookup a specific (type, state_key) pair for an event. It also makes it easy
-- to read the state for a given state_block_nid ordered by (type, state_key)
-- which in turn makes it easier to merge state data blocks.
CREATE SEQUENCE IF NOT EXISTS roomserver_state_block_nid_seq;
CREATE TABLE IF NOT EXISTS roomserver_state_block (
-- Local numeric ID for this state data.
state_block_nid bigint NOT NULL,
event_type_nid bigint NOT NULL,
event_state_key_nid bigint NOT NULL,
event_nid bigint NOT NULL,
UNIQUE (state_block_nid, event_type_nid, event_state_key_nid)
);
`
const insertStateDataSQL = "" +
"INSERT INTO roomserver_state_block (state_block_nid, event_type_nid, event_state_key_nid, event_nid)" +
" VALUES ($1, $2, $3, $4)"
const selectNextStateBlockNIDSQL = "" +
"SELECT nextval('roomserver_state_block_nid_seq')"
// Bulk state lookup by numeric state block ID.
// Sort by the state_block_nid, event_type_nid, event_state_key_nid
// This means that all the entries for a given state_block_nid will appear
// together in the list and those entries will sorted by event_type_nid
// and event_state_key_nid. This property makes it easier to merge two
// state data blocks together.
const bulkSelectStateBlockEntriesSQL = "" +
"SELECT state_block_nid, event_type_nid, event_state_key_nid, event_nid" +
" FROM roomserver_state_block WHERE state_block_nid = ANY($1)" +
" ORDER BY state_block_nid, event_type_nid, event_state_key_nid"
// Bulk state lookup by numeric state block ID.
// Filters the rows in each block to the requested types and state keys.
// We would like to restrict to particular type state key pairs but we are
// restricted by the query language to pull the cross product of a list
// of types and a list state_keys. So we have to filter the result in the
// application to restrict it to the list of event types and state keys we
// actually wanted.
const bulkSelectFilteredStateBlockEntriesSQL = "" +
"SELECT state_block_nid, event_type_nid, event_state_key_nid, event_nid" +
" FROM roomserver_state_block WHERE state_block_nid = ANY($1)" +
" AND event_type_nid = ANY($2) AND event_state_key_nid = ANY($3)" +
" ORDER BY state_block_nid, event_type_nid, event_state_key_nid"
type stateBlockStatements struct {
insertStateDataStmt *sql.Stmt
selectNextStateBlockNIDStmt *sql.Stmt
bulkSelectStateBlockEntriesStmt *sql.Stmt
bulkSelectFilteredStateBlockEntriesStmt *sql.Stmt
}
func (s *stateBlockStatements) prepare(db *sql.DB) (err error) {
_, err = db.Exec(stateDataSchema)
if err != nil {
return
}
return statementList{
{&s.insertStateDataStmt, insertStateDataSQL},
{&s.selectNextStateBlockNIDStmt, selectNextStateBlockNIDSQL},
{&s.bulkSelectStateBlockEntriesStmt, bulkSelectStateBlockEntriesSQL},
{&s.bulkSelectFilteredStateBlockEntriesStmt, bulkSelectFilteredStateBlockEntriesSQL},
}.prepare(db)
}
func (s *stateBlockStatements) bulkInsertStateData(
ctx context.Context,
stateBlockNID types.StateBlockNID,
entries []types.StateEntry,
) error {
for _, entry := range entries {
_, err := s.insertStateDataStmt.ExecContext(
ctx,
int64(stateBlockNID),
int64(entry.EventTypeNID),
int64(entry.EventStateKeyNID),
int64(entry.EventNID),
)
if err != nil {
return err
}
}
return nil
}
func (s *stateBlockStatements) selectNextStateBlockNID(
ctx context.Context,
) (types.StateBlockNID, error) {
var stateBlockNID int64
err := s.selectNextStateBlockNIDStmt.QueryRowContext(ctx).Scan(&stateBlockNID)
return types.StateBlockNID(stateBlockNID), err
}
func (s *stateBlockStatements) bulkSelectStateBlockEntries(
ctx context.Context, stateBlockNIDs []types.StateBlockNID,
) ([]types.StateEntryList, error) {
nids := make([]int64, len(stateBlockNIDs))
for i := range stateBlockNIDs {
nids[i] = int64(stateBlockNIDs[i])
}
rows, err := s.bulkSelectStateBlockEntriesStmt.QueryContext(ctx, pq.Int64Array(nids))
if err != nil {
return nil, err
}
defer rows.Close() // nolint: errcheck
results := make([]types.StateEntryList, len(stateBlockNIDs))
// current is a pointer to the StateEntryList to append the state entries to.
var current *types.StateEntryList
i := 0
for rows.Next() {
var (
stateBlockNID int64
eventTypeNID int64
eventStateKeyNID int64
eventNID int64
entry types.StateEntry
)
if err := rows.Scan(
&stateBlockNID, &eventTypeNID, &eventStateKeyNID, &eventNID,
); err != nil {
return nil, err
}
entry.EventTypeNID = types.EventTypeNID(eventTypeNID)
entry.EventStateKeyNID = types.EventStateKeyNID(eventStateKeyNID)
entry.EventNID = types.EventNID(eventNID)
if current == nil || types.StateBlockNID(stateBlockNID) != current.StateBlockNID {
// The state entry row is for a different state data block to the current one.
// So we start appending to the next entry in the list.
current = &results[i]
current.StateBlockNID = types.StateBlockNID(stateBlockNID)
i++
}
current.StateEntries = append(current.StateEntries, entry)
}
if i != len(stateBlockNIDs) {
return nil, fmt.Errorf("storage: state data NIDs missing from the database (%d != %d)", i, len(stateBlockNIDs))
}
return results, nil
}
func (s *stateBlockStatements) bulkSelectFilteredStateBlockEntries(
ctx context.Context,
stateBlockNIDs []types.StateBlockNID,
stateKeyTuples []types.StateKeyTuple,
) ([]types.StateEntryList, error) {
tuples := stateKeyTupleSorter(stateKeyTuples)
// Sort the tuples so that we can run binary search against them as we filter the rows returned by the db.
sort.Sort(tuples)
eventTypeNIDArray, eventStateKeyNIDArray := tuples.typesAndStateKeysAsArrays()
rows, err := s.bulkSelectFilteredStateBlockEntriesStmt.QueryContext(
ctx,
stateBlockNIDsAsArray(stateBlockNIDs),
eventTypeNIDArray,
eventStateKeyNIDArray,
)
if err != nil {
return nil, err
}
defer rows.Close() // nolint: errcheck
var results []types.StateEntryList
var current types.StateEntryList
for rows.Next() {
var (
stateBlockNID int64
eventTypeNID int64
eventStateKeyNID int64
eventNID int64
entry types.StateEntry
)
if err := rows.Scan(
&stateBlockNID, &eventTypeNID, &eventStateKeyNID, &eventNID,
); err != nil {
return nil, err
}
entry.EventTypeNID = types.EventTypeNID(eventTypeNID)
entry.EventStateKeyNID = types.EventStateKeyNID(eventStateKeyNID)
entry.EventNID = types.EventNID(eventNID)
// We can use binary search here because we sorted the tuples earlier
if !tuples.contains(entry.StateKeyTuple) {
// The select will return the cross product of types and state keys.
// So we need to check if type of the entry is in the list.
continue
}
if types.StateBlockNID(stateBlockNID) != current.StateBlockNID {
// The state entry row is for a different state data block to the current one.
// So we append the current entry to the results and start adding to a new one.
// The first time through the loop current will be empty.
if current.StateEntries != nil {
results = append(results, current)
}
current = types.StateEntryList{StateBlockNID: types.StateBlockNID(stateBlockNID)}
}
current.StateEntries = append(current.StateEntries, entry)
}
// Add the last entry to the list if it is not empty.
if current.StateEntries != nil {
results = append(results, current)
}
return results, nil
}
func stateBlockNIDsAsArray(stateBlockNIDs []types.StateBlockNID) pq.Int64Array {
nids := make([]int64, len(stateBlockNIDs))
for i := range stateBlockNIDs {
nids[i] = int64(stateBlockNIDs[i])
}
return pq.Int64Array(nids)
}
type stateKeyTupleSorter []types.StateKeyTuple
func (s stateKeyTupleSorter) Len() int { return len(s) }
func (s stateKeyTupleSorter) Less(i, j int) bool { return s[i].LessThan(s[j]) }
func (s stateKeyTupleSorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
// Check whether a tuple is in the list. Assumes that the list is sorted.
func (s stateKeyTupleSorter) contains(value types.StateKeyTuple) bool {
i := sort.Search(len(s), func(i int) bool { return !s[i].LessThan(value) })
return i < len(s) && s[i] == value
}
// List the unique eventTypeNIDs and eventStateKeyNIDs.
// Assumes that the list is sorted.
func (s stateKeyTupleSorter) typesAndStateKeysAsArrays() (eventTypeNIDs pq.Int64Array, eventStateKeyNIDs pq.Int64Array) {
eventTypeNIDs = make(pq.Int64Array, len(s))
eventStateKeyNIDs = make(pq.Int64Array, len(s))
for i := range s {
eventTypeNIDs[i] = int64(s[i].EventTypeNID)
eventStateKeyNIDs[i] = int64(s[i].EventStateKeyNID)
}
eventTypeNIDs = eventTypeNIDs[:util.SortAndUnique(int64Sorter(eventTypeNIDs))]
eventStateKeyNIDs = eventStateKeyNIDs[:util.SortAndUnique(int64Sorter(eventStateKeyNIDs))]
return
}
type int64Sorter []int64
func (s int64Sorter) Len() int { return len(s) }
func (s int64Sorter) Less(i, j int) bool { return s[i] < s[j] }
func (s int64Sorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }