.

go/zodb/storage/fs1/filestorage.go

@@ -892,8 +892,74 @@ func (fs *FileStorage) Load(xid zodb.Xid) (data []byte, tid zodb.Tid, err error)
 	return data, tid, nil
 }
 
+// --- raw iteration ---
 
-// zodb.IStorage iteration
+// TxnIter is iterator over transaction records
+type TxnIter struct {
+	fsSeq *xbufio.SeqReaderAt
+
+	Txnh	TxnHeader	// current transaction record information
+	Flags	iterFlags	// XXX iterate forward (> 0) / backward (< 0) / EOF reached (== 0)
+}
+
+// DataIter is iterator over data records inside one transaction
+type DataIter struct {
+	fsSeq *xbufio.SeqReaderAt
+
+	Txnh	*TxnHeader	// header of transaction we are iterating inside
+	Datah	DataHeader	// current data record information
+}
+
+// Iter is combined 2-level iterator over transaction and data records
+type Iter struct {
+	TxnIter
+	DataIter
+}
+
+
+// NextTxn iterates to next/previous transaction record according to iteration direction
+func (ti *TxnIter) NextTxn(flags TxnLoadFlags) error {
+	var err error
+	if ti.Flags & iterDir != 0 {
+		err = ti.Txnh.LoadNext(ti.fsSeq, flags)
+	} else {
+		err = ti.Txnh.LoadPrev(ti.fsSeq, flags)
+	}
+
+	//fmt.Println("loaded:", ti.Txnh.Tid)
+	return err
+}
+
+// NextData iterates to next data record header
+func (di *DataIter) NextData() error {
+	return di.Datah.LoadNext(di.fsSeq, di.Txnh)
+}
+
+// NextTxn iterates to next transaction record and resets data iterator to iterate inside it
+func (iter *Iter) NextTxn() error {
+	err := iter.TxnIter.NextTxn()
+	if err != nil {
+		return err
+	}
+
+	// set .DataIter to iterate over .TxnIter.Txnh
+	iter.DataIter.Datah.Pos = fsi.txnIter.Txnh.DataPos()
+	iter.DataIter.Datah.DataLen = -DataHeaderSize // first iteration will go to first data record
+}
+
+// IterateRaw ... XXX
+func (fs *FileStorage) IterateRaw(dir/*XXX fwd/back*/) *Iter {
+	// when iterating use IO optimized for sequential access
+	fsSeq := xbufio.NewSeqReaderAt(fs.file)
+	// XXX setup .TxnIter.dir and start
+	iter.TxnIter.fsSeq = fsSeq
+	iter.DataIter.fsSeq = fsSeq
+	iter.DataIter.Txnh = &iter.txnIter.Txnh
+	return iter
+}
+
+
+// --- zodb.IStorage iteration ---
 
 type iterFlags int
 const (
@@ -902,61 +968,41 @@ const (
 	iterPreloaded                       // data for this iteration was already preloaded
 )
 
-// txnIter is iterator over transaction records
-type txnIter struct {
-	fsSeq *xbufio.SeqReaderAt
+// zIter is transaction/data-records iterator as specified by zodb.IStorage
+type zIter struct {
+	iter Iter
 
-	Txnh	TxnHeader	// current transaction information
 	TidStop	zodb.Tid	// iterate up to tid <= tidStop | tid >= tidStop depending on .dir
 
-	Flags	iterFlags	// iterate forward (> 0) / backward (< 0) / EOF reached (== 0)
-}
-
-// dataIter is iterator over data records inside one transaction
-type dataIter struct {
-	fsSeq *xbufio.SeqReaderAt
-
-	Txnh	*TxnHeader	// header of transaction we are iterating inside
-	Datah	DataHeader
+	Flags	iterFlags
 
 	// data header for data loading
-	// XXX need to use separate dh because x.LoadData() changes x state while going through backpointers.
-	// XXX here to avoid allocations
+	// ( NOTE: need to use separate dh because x.LoadData() changes x state
+	//   while going through backpointers.
+	//
+	//   here to avoid allocations )
 	dhLoading DataHeader
 
 	sri	zodb.StorageRecordInformation // ptr to this will be returned by NextData
 	dataBuf	[]byte
 }
 
-// iterator is transaction/data-records iterator as specified by zodb.IStorage
-type iterator struct {
-	txnIter  txnIter
-	dataIter dataIter
-}
-
-
-func (ti *txnIter) NextTxn(flags TxnLoadFlags) error {
+// NextTxn iterates to next/previous transaction record according to iteration direction
+func (zi *zIter) NextTxn() (*zodb.TxnInfo, zodb.IStorageRecordIterator, error) {
 	switch {
 	case ti.Flags & iterEOF != 0:
 		//println("already eof")
 		return io.EOF
 
+	// XXX needed?
 	case ti.Flags & iterPreloaded != 0:
-		// first element is already there - preloaded by who initialized txnIter
+		// first element is already there - preloaded by who initialized TxnIter
 		ti.Flags &= ^iterPreloaded
 		//fmt.Println("preloaded:", ti.Txnh.Tid)
 
 	default:
-		var err error
-		if ti.Flags & iterDir != 0 {
-			err = ti.Txnh.LoadNext(ti.fsSeq, flags)
-		} else {
-			err = ti.Txnh.LoadPrev(ti.fsSeq, flags)
-		}
+		err := zi.iter.NextTxn(LoadAll)
 		// XXX EOF ^^^ is not expected (range pre-cut to valid tids) ?
-
-		//fmt.Println("loaded:", ti.Txnh.Tid)
-
 		if err != nil {
 			return err
 		}
@@ -970,48 +1016,51 @@ func (ti *txnIter) NextTxn(flags TxnLoadFlags) error {
 		return io.EOF
 	}
 
-	return nil
+	return &zi.iter.Txnh.TxnInfo, zi, nil
 }
 
-func (di *dataIter) NextData() (*zodb.StorageRecordInformation, error) {
-	err := di.Datah.LoadNext(di.fsSeq, di.Txnh)
+// NextData iterates to next data record and loads data content
+func (zi *zIter) NextData() (*zodb.StorageRecordInformation, error) {
+	err := zi.iter.NextData()
 	if err != nil {
 		return nil, err	// XXX recheck
 	}
 
-	di.sri.Oid = di.Datah.Oid
-	di.sri.Tid = di.Datah.Tid
+	zi.sri.Oid = zi.iter.Datah.Oid
+	zi.sri.Tid = zi.iter.Datah.Tid
 
 	// NOTE dh.LoadData() changes dh state while going through backpointers -
 	// - need to use separate dh because of this
-	di.dhLoading = di.Datah
-	di.sri.Data = di.dataBuf
-	err = di.dhLoading.LoadData(di.fsSeq, &di.sri.Data)
+	zi.dhLoading = zi.iter.Datah
+	zi.sri.Data = zi.dataBuf
+	err = zi.dhLoading.LoadData(zi.iter.DataIter.fsSeq, &zi.sri.Data)
 	if err != nil {
 		return nil, err	// XXX recheck
 	}
 
 	// if memory was reallocated - use it next time
-	if cap(di.sri.Data) > cap(di.dataBuf) {
-		di.dataBuf = di.sri.Data
+	if cap(zi.sri.Data) > cap(zi.dataBuf) {
+		zi.dataBuf = zi.sri.Data
 	}
 
-	di.sri.DataTid = di.dhLoading.Tid
-	return &di.sri, nil
+	zi.sri.DataTid = zi.dhLoading.Tid
+	return &zi.sri, nil
 }
 
 
-func (fsi *iterator) NextTxn() (*zodb.TxnInfo, zodb.IStorageRecordIterator, error) {
-	err := fsi.txnIter.NextTxn(LoadAll)
-	if err != nil {
-		return nil, nil, err	// XXX recheck
-	}
 
-	// set .dataIter to iterate over .txnIter.Txnh
-	fsi.dataIter.Datah.Pos = fsi.txnIter.Txnh.DataPos()
-	fsi.dataIter.Datah.DataLen = -DataHeaderSize // first iteration will go to first data record
 
-	return &fsi.txnIter.Txnh.TxnInfo, &fsi.dataIter, nil
+// iterStartError is the iterator created when there are preparatory errors
+// this way we offload clients, besides handling NextTxn errors, from also
+// handling error cases from Iterate.
+//
+// XXX bad idea? (e.g. it will prevent from devirtualizing what Iterate returns)
+type iterStartError struct {
+	err error
+}
+
+func (e *iterStartError) NextTxn(*zodb.TxnInfo, zodb.IStorageIterator, error) {
+	return nil, nil, e.err
 }
 
 func (fs *FileStorage) Iterate(tidMin, tidMax zodb.Tid) zodb.IStorageIterator {
@@ -1024,14 +1073,15 @@ func (fs *FileStorage) Iterate(tidMin, tidMax zodb.Tid) zodb.IStorageIterator {
 		tidMax = fs.txnhMax.Tid
 	}
 
-	// XXX naming
-	Iter := iterator{}
+	// XXX naming	-> ziter?
+	ziter := &zIter{iter}
 
 	// when iterating use IO optimized for sequential access
+	// XXX -> IterateRaw
 	fsSeq := xbufio.NewSeqReaderAt(fs.file)
-	Iter.txnIter.fsSeq = fsSeq
-	Iter.dataIter.fsSeq = fsSeq
-	Iter.dataIter.Txnh = &Iter.txnIter.Txnh
+	iter.txnIter.fsSeq = fsSeq
+	iter.dataIter.fsSeq = fsSeq
+	iter.dataIter.Txnh = &iter.txnIter.Txnh
 
 	if tidMin > tidMax {
 		Iter.txnIter.Flags |= iterEOF	// empty
@@ -1065,7 +1115,7 @@ func (fs *FileStorage) Iterate(tidMin, tidMax zodb.Tid) zodb.IStorageIterator {
 	}
 
 	if err != nil {
-		panic(err)	// XXX
+		return &iterStartError{err}	// XXX err ctx
 	}
 
 	//fmt.Printf("tidRange: %v..%v -> found %v @%v\n", tidMin, tidMax, iter.Txnh.Tid, iter.Txnh.Pos)
@@ -1075,9 +1125,9 @@ func (fs *FileStorage) Iterate(tidMin, tidMax zodb.Tid) zodb.IStorageIterator {
 	iter.Flags &= ^iterEOF
 	if iter.Flags&iterDir != 0 {
 		// when ^^^ we were searching forward first txn was already found
-		err = iter.Txnh.loadStrings(fs.file)	// XXX ok?	XXX -> move NextTxn() ?
+		err = iter.Txnh.loadStrings(fsSeq)	// XXX ok?	XXX -> move NextTxn() ?
 		if err != nil {
-			panic(err)	// XXX
+			return &iterStartError{err}
 		}
 		iter.Flags |= iterPreloaded
 	}

go/zodb/storage/fs1/fs1tools/dump_test.go

+// Copyright (C) 2017  Nexedi SA and Contributors.
+//                     Kirill Smelkov <kirr@nexedi.com>
+//
+// This program is free software: you can Use, Study, Modify and Redistribute
+// it under the terms of the GNU General Public License version 3, or (at your
+// option) any later version, as published by the Free Software Foundation.
+//
+// You can also Link and Combine this program with other software covered by
+// the terms of any of the Free Software licenses or any of the Open Source
+// Initiative approved licenses and Convey the resulting work. Corresponding
+// source of such a combination shall include the source code for all other
+// software used.
+//
+// This program is distributed WITHOUT ANY WARRANTY; without even the implied
+// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+//
+// See COPYING file for full licensing terms.
+// See https://www.nexedi.com/licensing for rationale and options.
+
+package fs1tools
+
+//go:generate sh -c "python2 -c 'from ZODB.FileStorage import fsdump; fsdump.main()' ../testdata/1.fs >testdata/1.fsdump.ok"
+//go:generate sh -c "python2 -c 'from ZODB.FileStorage.fsdump import Dumper; import sys; d = Dumper(sys.argv[1]); d.dump()' ../testdata/1.fs >testdata/1.fsdumpv.ok"

go/zodb/storage/fs1/fs1tools/testdata/1.fsdump.ok

+Trans #00000 tid=0285cbac258bf266 time=1979-01-03 21:00:08.800000 offset=52
+    status=' ' user='' description='initial database creation'
+  data #00000 oid=0000000000000000 size=57 class=persistent.mapping.PersistentMapping
+Trans #00001 tid=0285cbac3d0369e6 time=1979-01-03 21:00:14.300000 offset=250
+    status=' ' user='user0.0' description='step 0.0'
+  data #00000 oid=0000000000000000 size=95 class=persistent.mapping.PersistentMapping
+  data #00001 oid=0000000000000001 size=29 class=__main__.Object
+Trans #00002 tid=0285cbac41b4e833 time=1979-01-03 21:00:15.400000 offset=557
+    status=' ' user='user0.1' description='step 0.1'
+  data #00000 oid=0000000000000000 size=116 class=persistent.mapping.PersistentMapping
+  data #00001 oid=0000000000000002 size=29 class=__main__.Object
+Trans #00003 tid=0285cbac46666680 time=1979-01-03 21:00:16.500000 offset=885
+    status=' ' user='user0.2' description='step 0.2'
+  data #00000 oid=0000000000000000 size=136 class=persistent.mapping.PersistentMapping
+  data #00001 oid=0000000000000003 size=29 class=__main__.Object
+Trans #00004 tid=0285cbac4b17e4cc time=1979-01-03 21:00:17.600000 offset=1233
+    status=' ' user='user0.3' description='step 0.3'
+  data #00000 oid=0000000000000002 size=29 class=__main__.Object
+Trans #00005 tid=0285cbac4fc96319 time=1979-01-03 21:00:18.700000 offset=1403
+    status=' ' user='user0.4' description='step 0.4'
+  data #00000 oid=0000000000000000 size=156 class=persistent.mapping.PersistentMapping
+  data #00001 oid=0000000000000004 size=29 class=__main__.Object
+Trans #00006 tid=0285cbac547ae166 time=1979-01-03 21:00:19.800000 offset=1771
+    status=' ' user='user0.5' description='step 0.5'
+  data #00000 oid=0000000000000000 size=176 class=persistent.mapping.PersistentMapping
+  data #00001 oid=0000000000000005 size=29 class=__main__.Object
+Trans #00007 tid=0285cbac592c5fb3 time=1979-01-03 21:00:20.900000 offset=2159
+    status=' ' user='user0.6' description='step 0.6'
+  data #00000 oid=0000000000000004 size=29 class=__main__.Object
+Trans #00008 tid=0285cbac5dddde00 time=1979-01-03 21:00:22.000000 offset=2329
+    status=' ' user='user0.7' description='step 0.7'
+  data #00000 oid=0000000000000005 size=29 class=__main__.Object
+Trans #00009 tid=0285cbac628f5c4c time=1979-01-03 21:00:23.100000 offset=2499
+    status=' ' user='user0.8' description='step 0.8'
+  data #00000 oid=0000000000000000 size=196 class=persistent.mapping.PersistentMapping
+  data #00001 oid=0000000000000006 size=29 class=__main__.Object
+Trans #00010 tid=0285cbac6740da99 time=1979-01-03 21:00:24.200001 offset=2907
+    status=' ' user='user0.9' description='step 0.9'
+  data #00000 oid=0000000000000006 size=29 class=__main__.Object
+Trans #00011 tid=0285cbac6bf258e6 time=1979-01-03 21:00:25.300001 offset=3079
+    status=' ' user='user0.10' description='step 0.10'
+  data #00000 oid=0000000000000003 size=30 class=__main__.Object
+Trans #00012 tid=0285cbac70a3d733 time=1979-01-03 21:00:26.400001 offset=3252
+    status=' ' user='user0.11' description='step 0.11'
+  data #00000 oid=0000000000000003 size=30 class=__main__.Object
+Trans #00013 tid=0285cbac75555580 time=1979-01-03 21:00:27.500001 offset=3425
+    status=' ' user='user0.12' description='step 0.12'
+  data #00000 oid=0000000000000001 size=30 class=__main__.Object
+Trans #00014 tid=0285cbac7a06d3cc time=1979-01-03 21:00:28.600001 offset=3598
+    status=' ' user='user0.13' description='step 0.13'
+  data #00000 oid=0000000000000005 size=30 class=__main__.Object
+Trans #00015 tid=0285cbac7eb85219 time=1979-01-03 21:00:29.700001 offset=3771
+    status=' ' user='user0.14' description='step 0.14'
+  data #00000 oid=0000000000000005 size=30 class=__main__.Object
+Trans #00016 tid=0285cbac8369d066 time=1979-01-03 21:00:30.800001 offset=3944
+    status=' ' user='user0.15' description='step 0.15'
+  data #00000 oid=0000000000000006 size=30 class=__main__.Object
+Trans #00017 tid=0285cbac881b4eb3 time=1979-01-03 21:00:31.900001 offset=4117
+    status=' ' user='user0.16' description='step 0.16'
+  data #00000 oid=0000000000000005 size=30 class=__main__.Object
+Trans #00018 tid=0285cbac8ccccd00 time=1979-01-03 21:00:33.000001 offset=4290
+    status=' ' user='user0.17' description='step 0.17'
+  data #00000 oid=0000000000000004 size=30 class=__main__.Object
+Trans #00019 tid=0285cbac917e4b4c time=1979-01-03 21:00:34.100001 offset=4463
+    status=' ' user='user0.18' description='step 0.18'
+  data #00000 oid=0000000000000004 size=30 class=__main__.Object
+Trans #00020 tid=0285cbac962fc999 time=1979-01-03 21:00:35.200001 offset=4636
+    status=' ' user='user0.19' description='step 0.19'
+  data #00000 oid=0000000000000005 size=30 class=__main__.Object
+Trans #00021 tid=0285cbac9ae147e6 time=1979-01-03 21:00:36.300001 offset=4809
+    status=' ' user='user0.20' description='step 0.20'
+  data #00000 oid=0000000000000002 size=30 class=__main__.Object
+Trans #00022 tid=0285cbac9f92c633 time=1979-01-03 21:00:37.400001 offset=4982
+    status=' ' user='user0.21' description='step 0.21'
+  data #00000 oid=0000000000000002 size=30 class=__main__.Object
+Trans #00023 tid=0285cbaca4444480 time=1979-01-03 21:00:38.500001 offset=5155
+    status=' ' user='user0.22' description='step 0.22'
+  data #00000 oid=0000000000000000 size=216 class=persistent.mapping.PersistentMapping
+  data #00001 oid=0000000000000007 size=30 class=__main__.Object
+Trans #00024 tid=0285cbaca8f5c2cc time=1979-01-03 21:00:39.600001 offset=5586
+    status=' ' user='user0.23' description='step 0.23'
+  data #00000 oid=0000000000000007 size=30 class=__main__.Object
+Trans #00025 tid=0285cbacada74119 time=1979-01-03 21:00:40.700001 offset=5759
+    status=' ' user='user0.24' description='step 0.24'
+  data #00000 oid=0000000000000003 size=30 class=__main__.Object
+Trans #00026 tid=0285cbacb258bf66 time=1979-01-03 21:00:41.800001 offset=5995
+    status=' ' user='root0.0\nYour\nMagesty ' description='undo 0.0\nmore detailed description\n\nzzz ...'
+  data #00000 oid=0000000000000007 size=30 class=__main__.Object bp=0285cbaca4444480
+Trans #00027 tid=0285cbacb70a3db3 time=1979-01-03 21:00:42.900001 offset=6210
+    status=' ' user='root0.1\nYour\nMagesty ' description='undo 0.1\nmore detailed description\n\nzzz ...\t'
+  data #00000 oid=0000000000000003 size=30 class=__main__.Object bp=0285cbac70a3d733
+Trans #00028 tid=0285cbacbbbbbc00 time=1979-01-03 21:00:44.000001 offset=6302
+    status=' ' user='' description='predelete 7'
+  data #00000 oid=0000000000000000 size=216 class=persistent.mapping.PersistentMapping
+  data #00001 oid=0000000000000008 size=28 class=__main__.Object
+Trans #00029 tid=0285cbacc06d3a4c time=1979-01-03 21:00:45.100001 offset=6826
+    status=' ' user="root0\nYour\nRoyal\nMagesty' \x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f" description='delete 0\nalpha beta gamma\'delta"lambda\n\nqqq ...'
+  data #00000 oid=0000000000000007 class=undo or abort of object creation
+Trans #00030 tid=0285cbacfd70a433 time=1979-01-03 21:00:59.400001 offset=6975
+    status=' ' user='user1.0' description='step 1.0'
+  data #00000 oid=0000000000000008 size=29 class=__main__.Object
+Trans #00031 tid=0285cbad02222280 time=1979-01-03 21:01:00.500001 offset=7145
+    status=' ' user='user1.1' description='step 1.1'
+  data #00000 oid=0000000000000006 size=29 class=__main__.Object
+Trans #00032 tid=0285cbad06d3a0cc time=1979-01-03 21:01:01.600001 offset=7315
+    status=' ' user='user1.2' description='step 1.2'
+  data #00000 oid=0000000000000004 size=29 class=__main__.Object
+Trans #00033 tid=0285cbad0b851f19 time=1979-01-03 21:01:02.700001 offset=7485
+    status=' ' user='user1.3' description='step 1.3'
+  data #00000 oid=0000000000000003 size=29 class=__main__.Object
+Trans #00034 tid=0285cbad10369d66 time=1979-01-03 21:01:03.800001 offset=7655
+    status=' ' user='user1.4' description='step 1.4'
+  data #00000 oid=0000000000000003 size=29 class=__main__.Object
+Trans #00035 tid=0285cbad14e81bb3 time=1979-01-03 21:01:04.900001 offset=7825
+    status=' ' user='user1.5' description='step 1.5'
+  data #00000 oid=0000000000000008 size=29 class=__main__.Object
+Trans #00036 tid=0285cbad19999a00 time=1979-01-03 21:01:06.000001 offset=7995
+    status=' ' user='user1.6' description='step 1.6'
+  data #00000 oid=0000000000000001 size=29 class=__main__.Object
+Trans #00037 tid=0285cbad1e4b184c time=1979-01-03 21:01:07.100001 offset=8165
+    status=' ' user='user1.7' description='step 1.7'
+  data #00000 oid=0000000000000002 size=29 class=__main__.Object
+Trans #00038 tid=0285cbad22fc9699 time=1979-01-03 21:01:08.200001 offset=8335
+    status=' ' user='user1.8' description='step 1.8'
+  data #00000 oid=0000000000000008 size=29 class=__main__.Object
+Trans #00039 tid=0285cbad27ae14e6 time=1979-01-03 21:01:09.300001 offset=8505
+    status=' ' user='user1.9' description='step 1.9'
+  data #00000 oid=0000000000000008 size=29 class=__main__.Object
+Trans #00040 tid=0285cbad2c5f9333 time=1979-01-03 21:01:10.400002 offset=8677
+    status=' ' user='user1.10' description='step 1.10'
+  data #00000 oid=0000000000000006 size=30 class=__main__.Object
+Trans #00041 tid=0285cbad31111180 time=1979-01-03 21:01:11.500002 offset=8850
+    status=' ' user='user1.11' description='step 1.11'
+  data #00000 oid=0000000000000005 size=30 class=__main__.Object
+Trans #00042 tid=0285cbad35c28fcc time=1979-01-03 21:01:12.600002 offset=9023
+    status=' ' user='user1.12' description='step 1.12'
+  data #00000 oid=0000000000000008 size=30 class=__main__.Object
+Trans #00043 tid=0285cbad3a740e19 time=1979-01-03 21:01:13.700002 offset=9196
+    status=' ' user='user1.13' description='step 1.13'
+  data #00000 oid=0000000000000006 size=30 class=__main__.Object
+Trans #00044 tid=0285cbad3f258c66 time=1979-01-03 21:01:14.800002 offset=9369
+    status=' ' user='user1.14' description='step 1.14'
+  data #00000 oid=0000000000000003 size=30 class=__main__.Object
+Trans #00045 tid=0285cbad43d70ab3 time=1979-01-03 21:01:15.900002 offset=9542
+    status=' ' user='user1.15' description='step 1.15'
+  data #00000 oid=0000000000000003 size=30 class=__main__.Object
+Trans #00046 tid=0285cbad48888900 time=1979-01-03 21:01:17.000002 offset=9715
+    status=' ' user='user1.16' description='step 1.16'
+  data #00000 oid=0000000000000002 size=30 class=__main__.Object
+Trans #00047 tid=0285cbad4d3a074c time=1979-01-03 21:01:18.100002 offset=9888
+    status=' ' user='user1.17' description='step 1.17'
+  data #00000 oid=0000000000000003 size=30 class=__main__.Object
+Trans #00048 tid=0285cbad51eb8599 time=1979-01-03 21:01:19.200002 offset=10061
+    status=' ' user='user1.18' description='step 1.18'
+  data #00000 oid=0000000000000001 size=30 class=__main__.Object
+Trans #00049 tid=0285cbad569d03e6 time=1979-01-03 21:01:20.300002 offset=10234
+    status=' ' user='user1.19' description='step 1.19'
+  data #00000 oid=0000000000000005 size=30 class=__main__.Object
+Trans #00050 tid=0285cbad5b4e8233 time=1979-01-03 21:01:21.400002 offset=10407
+    status=' ' user='user1.20' description='step 1.20'
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go/zodb/zodb.go

@@ -165,6 +165,7 @@ type IStorage interface {
 	// tpc_finish(txn, callback)    XXX clarify about callback
 	// tpc_abort(txn)
 
+	// XXX text
 	Iterate(tidMin, tidMax Tid) IStorageIterator	// XXX , error ?
 }