.

go/zodb/connection.go

@@ -224,6 +224,8 @@ func (conn *Connection) load(ctx context.Context, oid Oid) (_ *mem.Buf, serial T
 // ----------------------------------------
 
 // checkTxnCtx asserts that current transaction is the same as conn.txn .
+//
+// XXX swap naming?
 func (conn *Connection) checkTxnCtx(ctx context.Context, who string) {
 	conn.checkTxn(transaction.Current(ctx), who)
 }

go/zodb/db.go

@@ -16,6 +16,7 @@ package zodb
 
 import (
 	"context"
+	"sort"
 	"sync"
 
 	"lab.nexedi.com/kirr/neo/go/transaction"
@@ -38,7 +39,16 @@ type DB struct {
 	stor	IStorage
 
 	mu	sync.Mutex
-	connv	[]*Connection
+	connv	[]*Connection // order by ↑= .at
+
+	// information about invalidations
+	invTab	[]invEntry // order by ↑= .tid
+}
+
+// invEntry describes invalidations caused by a database transaction.
+type invEntry struct {
+	tid	Tid
+	oidv	[]Oid
 }
 
 
@@ -49,17 +59,17 @@ func NewDB(stor IStorage) *DB {
 	return &DB{stor: stor}
 }
 
-// Open opens new connection to the database.
+// Open opens new connection to the database. XXX @lastTid
 //
 // XXX must be called under transaction.
+// XXX connectin must be used under the same transaction only.
 //
 // XXX text
 func (db *DB) Open(ctx context.Context) *Connection {
 	txn := transaction.Current(ctx)
-
 	conn := db.get()
 
-	// XXX sync storage for lastTid -> conn.at
+	// XXX sync storage for lastTid; process invalidations  [conn.at, lastTid]
 
 	conn.txn = txn
 	txn.RegisterSync((*connTxnSync)(conn))
@@ -95,14 +105,20 @@ func (db *DB) get() *Connection {
 func (db *DB) put(conn *Connection) {
 	// XXX assert conn.db == db
 	conn.txn = nil
-	//XXX want to do this; but also need to preserve info at..last_tid to process invalidations
-	//conn.at  = 0
 
 	db.mu.Lock()
 	defer db.mu.Unlock()
 
 	// XXX check if len(connv) > X, and drop conn if yes
-	db.connv = append(db.connv, conn)
+	// [i-1].at ≤ at < [i].at
+	i := sort.Search(len(db.connv), func(i int) bool {
+		return conn.at < db.connv[i].at
+	})
+
+	//db.connv = append(db.connv[:i], conn, db.connv[i:]...)
+	db.connv = append(db.connv, nil)
+	copy(db.connv[i+1:], db.connv[i:])
+	db.connv[i] = conn
 }
 
 // ---- txn sync ----
@@ -115,10 +131,10 @@ func (csync *connTxnSync) BeforeCompletion(txn transaction.Transaction) {
 	// nothing
 }
 
+// AfterCompletion puts conn back into db pool after transaction is complete.
 func (csync *connTxnSync) AfterCompletion(txn transaction.Transaction) {
 	conn := (*Connection)(csync)
 	conn.checkTxn(txn, "AfterCompletion")
 
-	// put conn back into db pool.
 	conn.db.put(conn)
 }