dendrite/roomserver/storage/postgres/state_block_table.go

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// 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 postgres
import (
"context"
"database/sql"
"fmt"
"sort"
"github.com/lib/pq"
"github.com/matrix-org/dendrite/internal"
"github.com/matrix-org/dendrite/roomserver/storage/shared"
"github.com/matrix-org/dendrite/roomserver/storage/tables"
"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 internal 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 (
-- The state snapshot NID that identifies this snapshot.
state_block_nid bigint PRIMARY KEY DEFAULT nextval('roomserver_state_block_nid_seq'),
-- The hash of the state block, 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_block_hash BYTEA UNIQUE,
-- The event NIDs contained within the state block.
event_nids bigint[] NOT NULL
);
`
// Insert a new state block. 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 block.
const insertStateDataSQL = "" +
"INSERT INTO roomserver_state_block (state_block_hash, event_nids)" +
" VALUES ($1, $2)" +
" ON CONFLICT (state_block_hash) DO UPDATE SET event_nids=$2" +
" RETURNING state_block_nid"
const bulkSelectStateBlockEntriesSQL = "" +
"SELECT state_block_nid, event_nids" +
" FROM roomserver_state_block WHERE state_block_nid = ANY($1) ORDER BY state_block_nid ASC"
type stateBlockStatements struct {
insertStateDataStmt *sql.Stmt
bulkSelectStateBlockEntriesStmt *sql.Stmt
}
func createStateBlockTable(db *sql.DB) error {
_, err := db.Exec(stateDataSchema)
return err
}
func prepareStateBlockTable(db *sql.DB) (tables.StateBlock, error) {
s := &stateBlockStatements{}
return s, shared.StatementList{
{&s.insertStateDataStmt, insertStateDataSQL},
{&s.bulkSelectStateBlockEntriesStmt, bulkSelectStateBlockEntriesSQL},
}.Prepare(db)
}
func (s *stateBlockStatements) BulkInsertStateData(
ctx context.Context,
txn *sql.Tx,
entries types.StateEntries,
) (id types.StateBlockNID, err error) {
entries = entries[:util.SortAndUnique(entries)]
var nids types.EventNIDs
for _, e := range entries {
nids = append(nids, e.EventNID)
}
err = s.insertStateDataStmt.QueryRowContext(
ctx, nids.Hash(), eventNIDsAsArray(nids),
).Scan(&id)
return
}
func (s *stateBlockStatements) BulkSelectStateBlockEntries(
ctx context.Context, stateBlockNIDs types.StateBlockNIDs,
) ([][]types.EventNID, error) {
rows, err := s.bulkSelectStateBlockEntriesStmt.QueryContext(ctx, stateBlockNIDsAsArray(stateBlockNIDs))
if err != nil {
return nil, err
}
defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectStateBlockEntries: rows.close() failed")
results := make([][]types.EventNID, len(stateBlockNIDs))
i := 0
for ; rows.Next(); i++ {
var stateBlockNID types.StateBlockNID
var result pq.Int64Array
if err = rows.Scan(&stateBlockNID, &result); err != nil {
return nil, err
}
r := []types.EventNID{}
for _, e := range result {
r = append(r, types.EventNID(e))
}
results[i] = r
}
if err = rows.Err(); err != nil {
return nil, err
}
if i != len(stateBlockNIDs) {
return nil, fmt.Errorf("storage: state data NIDs missing from the database (%d != %d)", i, len(stateBlockNIDs))
}
return results, err
}
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] }