diff --git a/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/protobuf.dart b/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/protobuf.dart
index fd31971c76..79780212c2 100644
--- a/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/protobuf.dart
+++ b/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/protobuf.dart
@@ -2,5 +2,6 @@
 export './ws.pb.dart';
 export './observable.pb.dart';
 export './errors.pb.dart';
+export './revision.pb.dart';
 export './event.pb.dart';
 export './doc.pb.dart';
diff --git a/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/revision.pb.dart b/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/revision.pb.dart
new file mode 100644
index 0000000000..152a95f90c
--- /dev/null
+++ b/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/revision.pb.dart
@@ -0,0 +1,101 @@
+///
+//  Generated code. Do not modify.
+//  source: revision.proto
+//
+// @dart = 2.12
+// ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
+
+import 'dart:core' as $core;
+
+import 'package:fixnum/fixnum.dart' as $fixnum;
+import 'package:protobuf/protobuf.dart' as $pb;
+
+class Revision extends $pb.GeneratedMessage {
+  static final $pb.BuilderInfo _i = $pb.BuilderInfo(const $core.bool.fromEnvironment('protobuf.omit_message_names') ? '' : 'Revision', createEmptyInstance: create)
+    ..aInt64(1, const $core.bool.fromEnvironment('protobuf.omit_field_names') ? '' : 'baseRevId')
+    ..aInt64(2, const $core.bool.fromEnvironment('protobuf.omit_field_names') ? '' : 'revId')
+    ..a<$core.List<$core.int>>(3, const $core.bool.fromEnvironment('protobuf.omit_field_names') ? '' : 'delta', $pb.PbFieldType.OY)
+    ..aOS(4, const $core.bool.fromEnvironment('protobuf.omit_field_names') ? '' : 'md5')
+    ..hasRequiredFields = false
+  ;
+
+  Revision._() : super();
+  factory Revision({
+    $fixnum.Int64? baseRevId,
+    $fixnum.Int64? revId,
+    $core.List<$core.int>? delta,
+    $core.String? md5,
+  }) {
+    final _result = create();
+    if (baseRevId != null) {
+      _result.baseRevId = baseRevId;
+    }
+    if (revId != null) {
+      _result.revId = revId;
+    }
+    if (delta != null) {
+      _result.delta = delta;
+    }
+    if (md5 != null) {
+      _result.md5 = md5;
+    }
+    return _result;
+  }
+  factory Revision.fromBuffer($core.List<$core.int> i, [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) => create()..mergeFromBuffer(i, r);
+  factory Revision.fromJson($core.String i, [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) => create()..mergeFromJson(i, r);
+  @$core.Deprecated(
+  'Using this can add significant overhead to your binary. '
+  'Use [GeneratedMessageGenericExtensions.deepCopy] instead. '
+  'Will be removed in next major version')
+  Revision clone() => Revision()..mergeFromMessage(this);
+  @$core.Deprecated(
+  'Using this can add significant overhead to your binary. '
+  'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
+  'Will be removed in next major version')
+  Revision copyWith(void Function(Revision) updates) => super.copyWith((message) => updates(message as Revision)) as Revision; // ignore: deprecated_member_use
+  $pb.BuilderInfo get info_ => _i;
+  @$core.pragma('dart2js:noInline')
+  static Revision create() => Revision._();
+  Revision createEmptyInstance() => create();
+  static $pb.PbList<Revision> createRepeated() => $pb.PbList<Revision>();
+  @$core.pragma('dart2js:noInline')
+  static Revision getDefault() => _defaultInstance ??= $pb.GeneratedMessage.$_defaultFor<Revision>(create);
+  static Revision? _defaultInstance;
+
+  @$pb.TagNumber(1)
+  $fixnum.Int64 get baseRevId => $_getI64(0);
+  @$pb.TagNumber(1)
+  set baseRevId($fixnum.Int64 v) { $_setInt64(0, v); }
+  @$pb.TagNumber(1)
+  $core.bool hasBaseRevId() => $_has(0);
+  @$pb.TagNumber(1)
+  void clearBaseRevId() => clearField(1);
+
+  @$pb.TagNumber(2)
+  $fixnum.Int64 get revId => $_getI64(1);
+  @$pb.TagNumber(2)
+  set revId($fixnum.Int64 v) { $_setInt64(1, v); }
+  @$pb.TagNumber(2)
+  $core.bool hasRevId() => $_has(1);
+  @$pb.TagNumber(2)
+  void clearRevId() => clearField(2);
+
+  @$pb.TagNumber(3)
+  $core.List<$core.int> get delta => $_getN(2);
+  @$pb.TagNumber(3)
+  set delta($core.List<$core.int> v) { $_setBytes(2, v); }
+  @$pb.TagNumber(3)
+  $core.bool hasDelta() => $_has(2);
+  @$pb.TagNumber(3)
+  void clearDelta() => clearField(3);
+
+  @$pb.TagNumber(4)
+  $core.String get md5 => $_getSZ(3);
+  @$pb.TagNumber(4)
+  set md5($core.String v) { $_setString(3, v); }
+  @$pb.TagNumber(4)
+  $core.bool hasMd5() => $_has(3);
+  @$pb.TagNumber(4)
+  void clearMd5() => clearField(4);
+}
+
diff --git a/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/revision.pbenum.dart b/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/revision.pbenum.dart
new file mode 100644
index 0000000000..81d387d5be
--- /dev/null
+++ b/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/revision.pbenum.dart
@@ -0,0 +1,7 @@
+///
+//  Generated code. Do not modify.
+//  source: revision.proto
+//
+// @dart = 2.12
+// ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
+
diff --git a/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/revision.pbjson.dart b/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/revision.pbjson.dart
new file mode 100644
index 0000000000..ef2e3b1275
--- /dev/null
+++ b/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/revision.pbjson.dart
@@ -0,0 +1,23 @@
+///
+//  Generated code. Do not modify.
+//  source: revision.proto
+//
+// @dart = 2.12
+// ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields,deprecated_member_use_from_same_package
+
+import 'dart:core' as $core;
+import 'dart:convert' as $convert;
+import 'dart:typed_data' as $typed_data;
+@$core.Deprecated('Use revisionDescriptor instead')
+const Revision$json = const {
+  '1': 'Revision',
+  '2': const [
+    const {'1': 'base_rev_id', '3': 1, '4': 1, '5': 3, '10': 'baseRevId'},
+    const {'1': 'rev_id', '3': 2, '4': 1, '5': 3, '10': 'revId'},
+    const {'1': 'delta', '3': 3, '4': 1, '5': 12, '10': 'delta'},
+    const {'1': 'md5', '3': 4, '4': 1, '5': 9, '10': 'md5'},
+  ],
+};
+
+/// Descriptor for `Revision`. Decode as a `google.protobuf.DescriptorProto`.
+final $typed_data.Uint8List revisionDescriptor = $convert.base64Decode('CghSZXZpc2lvbhIeCgtiYXNlX3Jldl9pZBgBIAEoA1IJYmFzZVJldklkEhUKBnJldl9pZBgCIAEoA1IFcmV2SWQSFAoFZGVsdGEYAyABKAxSBWRlbHRhEhAKA21kNRgEIAEoCVIDbWQ1');
diff --git a/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/revision.pbserver.dart b/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/revision.pbserver.dart
new file mode 100644
index 0000000000..4797cc3361
--- /dev/null
+++ b/app_flowy/packages/flowy_sdk/lib/protobuf/flowy-document/revision.pbserver.dart
@@ -0,0 +1,9 @@
+///
+//  Generated code. Do not modify.
+//  source: revision.proto
+//
+// @dart = 2.12
+// ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields,deprecated_member_use_from_same_package
+
+export 'revision.pb.dart';
+
diff --git a/rust-lib/flowy-database/migrations/2021-09-22-074638_flowy-doc-op/up.sql b/rust-lib/flowy-database/migrations/2021-09-22-074638_flowy-doc-op/up.sql
index b7e0c538af..def7ef3ce5 100644
--- a/rust-lib/flowy-database/migrations/2021-09-22-074638_flowy-doc-op/up.sql
+++ b/rust-lib/flowy-database/migrations/2021-09-22-074638_flowy-doc-op/up.sql
@@ -1,7 +1,7 @@
 -- Your SQL goes here
 CREATE TABLE op_table (
-    base_rev BIGINT NOT NULL DEFAULT 0,
-    rev BIGINT NOT NULL PRIMARY KEY,
+    base_rev_id BIGINT NOT NULL DEFAULT 0,
+    rev_id BIGINT NOT NULL PRIMARY KEY,
     data BLOB NOT NULL DEFAULT (x''),
     md5 TEXT NOT NULL DEFAULT '',
     state INTEGER NOT NULL DEFAULT 0
diff --git a/rust-lib/flowy-database/src/schema.rs b/rust-lib/flowy-database/src/schema.rs
index 81b52a1d29..2a003445e0 100644
--- a/rust-lib/flowy-database/src/schema.rs
+++ b/rust-lib/flowy-database/src/schema.rs
@@ -22,9 +22,9 @@ table! {
 }
 
 table! {
-    op_table (rev) {
-        base_rev -> BigInt,
-        rev -> BigInt,
+    op_table (rev_id) {
+        base_rev_id -> BigInt,
+        rev_id -> BigInt,
         data -> Binary,
         md5 -> Text,
         state -> Integer,
diff --git a/rust-lib/flowy-derive/src/derive_cache/derive_cache.rs b/rust-lib/flowy-derive/src/derive_cache/derive_cache.rs
index 95cc70d716..fbdde1ed88 100644
--- a/rust-lib/flowy-derive/src/derive_cache/derive_cache.rs
+++ b/rust-lib/flowy-derive/src/derive_cache/derive_cache.rs
@@ -60,6 +60,7 @@ pub fn category_from_str(type_str: &str) -> TypeCategory {
         | "UpdateDocParams"
         | "DocDelta"
         | "QueryDocParams"
+        | "Revision"
         | "WsDocumentData"
         | "DocError"
         | "FFIRequest"
diff --git a/rust-lib/flowy-document/Cargo.toml b/rust-lib/flowy-document/Cargo.toml
index 3f5ad07d94..9e0e056af1 100644
--- a/rust-lib/flowy-document/Cargo.toml
+++ b/rust-lib/flowy-document/Cargo.toml
@@ -35,6 +35,8 @@ url = "2.2"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = {version = "1.0"}
 chrono = "0.4.19"
+futures-core = { version = "0.3", default-features = false }
+md5 = "0.7.0"
 
 [dev-dependencies]
 flowy-test = { path = "../flowy-test" }
diff --git a/rust-lib/flowy-document/src/entities/doc/mod.rs b/rust-lib/flowy-document/src/entities/doc/mod.rs
index 4d548bdd5e..3c607e690c 100644
--- a/rust-lib/flowy-document/src/entities/doc/mod.rs
+++ b/rust-lib/flowy-document/src/entities/doc/mod.rs
@@ -1,4 +1,6 @@
 mod doc;
 pub mod parser;
+mod revision;
 
 pub use doc::*;
+pub use revision::*;
diff --git a/rust-lib/flowy-document/src/entities/doc/revision.rs b/rust-lib/flowy-document/src/entities/doc/revision.rs
new file mode 100644
index 0000000000..b89ca8ccc7
--- /dev/null
+++ b/rust-lib/flowy-document/src/entities/doc/revision.rs
@@ -0,0 +1,27 @@
+use flowy_derive::ProtoBuf;
+
+#[derive(Debug, Clone, Default, ProtoBuf)]
+pub struct Revision {
+    #[pb(index = 1)]
+    pub base_rev_id: i64,
+
+    #[pb(index = 2)]
+    pub rev_id: i64,
+
+    #[pb(index = 3)]
+    pub delta: Vec<u8>,
+
+    #[pb(index = 4)]
+    pub md5: String,
+}
+
+impl Revision {
+    pub fn new(base_rev_id: i64, rev_id: i64, delta: Vec<u8>, md5: String) -> Revision {
+        Self {
+            base_rev_id,
+            rev_id,
+            delta,
+            md5,
+        }
+    }
+}
diff --git a/rust-lib/flowy-document/src/errors.rs b/rust-lib/flowy-document/src/errors.rs
index 45d3015b57..bac02d51d1 100644
--- a/rust-lib/flowy-document/src/errors.rs
+++ b/rust-lib/flowy-document/src/errors.rs
@@ -104,6 +104,10 @@ impl std::convert::From<serde_json::Error> for DocError {
     fn from(error: serde_json::Error) -> Self { DocError::internal().context(error) }
 }
 
+impl std::convert::From<protobuf::ProtobufError> for DocError {
+    fn from(e: protobuf::ProtobufError) -> Self { DocError::internal().context(e) }
+}
+
 // impl std::convert::From<::r2d2::Error> for DocError {
 //     fn from(error: r2d2::Error) -> Self {
 // ErrorBuilder::new(ErrorCode::InternalError).error(error).build() } }
diff --git a/rust-lib/flowy-document/src/module.rs b/rust-lib/flowy-document/src/module.rs
index 040b6666e0..58aaa64ead 100644
--- a/rust-lib/flowy-document/src/module.rs
+++ b/rust-lib/flowy-document/src/module.rs
@@ -1,6 +1,6 @@
 use std::sync::Arc;
 
-use bytes::Bytes;
+
 use diesel::SqliteConnection;
 use parking_lot::RwLock;
 
diff --git a/rust-lib/flowy-document/src/protobuf/model/mod.rs b/rust-lib/flowy-document/src/protobuf/model/mod.rs
index 92ccda63e6..eb8e589277 100644
--- a/rust-lib/flowy-document/src/protobuf/model/mod.rs
+++ b/rust-lib/flowy-document/src/protobuf/model/mod.rs
@@ -9,6 +9,9 @@ pub use observable::*;
 mod errors; 
 pub use errors::*; 
 
+mod revision; 
+pub use revision::*; 
+
 mod event; 
 pub use event::*; 
 
diff --git a/rust-lib/flowy-document/src/protobuf/model/revision.rs b/rust-lib/flowy-document/src/protobuf/model/revision.rs
new file mode 100644
index 0000000000..e6bbf22838
--- /dev/null
+++ b/rust-lib/flowy-document/src/protobuf/model/revision.rs
@@ -0,0 +1,327 @@
+// This file is generated by rust-protobuf 2.22.1. Do not edit
+// @generated
+
+// https://github.com/rust-lang/rust-clippy/issues/702
+#![allow(unknown_lints)]
+#![allow(clippy::all)]
+
+#![allow(unused_attributes)]
+#![cfg_attr(rustfmt, rustfmt::skip)]
+
+#![allow(box_pointers)]
+#![allow(dead_code)]
+#![allow(missing_docs)]
+#![allow(non_camel_case_types)]
+#![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
+#![allow(trivial_casts)]
+#![allow(unused_imports)]
+#![allow(unused_results)]
+//! Generated file from `revision.proto`
+
+/// Generated files are compatible only with the same version
+/// of protobuf runtime.
+// const _PROTOBUF_VERSION_CHECK: () = ::protobuf::VERSION_2_22_1;
+
+#[derive(PartialEq,Clone,Default)]
+pub struct Revision {
+    // message fields
+    pub base_rev_id: i64,
+    pub rev_id: i64,
+    pub delta: ::std::vec::Vec<u8>,
+    pub md5: ::std::string::String,
+    // special fields
+    pub unknown_fields: ::protobuf::UnknownFields,
+    pub cached_size: ::protobuf::CachedSize,
+}
+
+impl<'a> ::std::default::Default for &'a Revision {
+    fn default() -> &'a Revision {
+        <Revision as ::protobuf::Message>::default_instance()
+    }
+}
+
+impl Revision {
+    pub fn new() -> Revision {
+        ::std::default::Default::default()
+    }
+
+    // int64 base_rev_id = 1;
+
+
+    pub fn get_base_rev_id(&self) -> i64 {
+        self.base_rev_id
+    }
+    pub fn clear_base_rev_id(&mut self) {
+        self.base_rev_id = 0;
+    }
+
+    // Param is passed by value, moved
+    pub fn set_base_rev_id(&mut self, v: i64) {
+        self.base_rev_id = v;
+    }
+
+    // int64 rev_id = 2;
+
+
+    pub fn get_rev_id(&self) -> i64 {
+        self.rev_id
+    }
+    pub fn clear_rev_id(&mut self) {
+        self.rev_id = 0;
+    }
+
+    // Param is passed by value, moved
+    pub fn set_rev_id(&mut self, v: i64) {
+        self.rev_id = v;
+    }
+
+    // bytes delta = 3;
+
+
+    pub fn get_delta(&self) -> &[u8] {
+        &self.delta
+    }
+    pub fn clear_delta(&mut self) {
+        self.delta.clear();
+    }
+
+    // Param is passed by value, moved
+    pub fn set_delta(&mut self, v: ::std::vec::Vec<u8>) {
+        self.delta = v;
+    }
+
+    // Mutable pointer to the field.
+    // If field is not initialized, it is initialized with default value first.
+    pub fn mut_delta(&mut self) -> &mut ::std::vec::Vec<u8> {
+        &mut self.delta
+    }
+
+    // Take field
+    pub fn take_delta(&mut self) -> ::std::vec::Vec<u8> {
+        ::std::mem::replace(&mut self.delta, ::std::vec::Vec::new())
+    }
+
+    // string md5 = 4;
+
+
+    pub fn get_md5(&self) -> &str {
+        &self.md5
+    }
+    pub fn clear_md5(&mut self) {
+        self.md5.clear();
+    }
+
+    // Param is passed by value, moved
+    pub fn set_md5(&mut self, v: ::std::string::String) {
+        self.md5 = v;
+    }
+
+    // Mutable pointer to the field.
+    // If field is not initialized, it is initialized with default value first.
+    pub fn mut_md5(&mut self) -> &mut ::std::string::String {
+        &mut self.md5
+    }
+
+    // Take field
+    pub fn take_md5(&mut self) -> ::std::string::String {
+        ::std::mem::replace(&mut self.md5, ::std::string::String::new())
+    }
+}
+
+impl ::protobuf::Message for Revision {
+    fn is_initialized(&self) -> bool {
+        true
+    }
+
+    fn merge_from(&mut self, is: &mut ::protobuf::CodedInputStream<'_>) -> ::protobuf::ProtobufResult<()> {
+        while !is.eof()? {
+            let (field_number, wire_type) = is.read_tag_unpack()?;
+            match field_number {
+                1 => {
+                    if wire_type != ::protobuf::wire_format::WireTypeVarint {
+                        return ::std::result::Result::Err(::protobuf::rt::unexpected_wire_type(wire_type));
+                    }
+                    let tmp = is.read_int64()?;
+                    self.base_rev_id = tmp;
+                },
+                2 => {
+                    if wire_type != ::protobuf::wire_format::WireTypeVarint {
+                        return ::std::result::Result::Err(::protobuf::rt::unexpected_wire_type(wire_type));
+                    }
+                    let tmp = is.read_int64()?;
+                    self.rev_id = tmp;
+                },
+                3 => {
+                    ::protobuf::rt::read_singular_proto3_bytes_into(wire_type, is, &mut self.delta)?;
+                },
+                4 => {
+                    ::protobuf::rt::read_singular_proto3_string_into(wire_type, is, &mut self.md5)?;
+                },
+                _ => {
+                    ::protobuf::rt::read_unknown_or_skip_group(field_number, wire_type, is, self.mut_unknown_fields())?;
+                },
+            };
+        }
+        ::std::result::Result::Ok(())
+    }
+
+    // Compute sizes of nested messages
+    #[allow(unused_variables)]
+    fn compute_size(&self) -> u32 {
+        let mut my_size = 0;
+        if self.base_rev_id != 0 {
+            my_size += ::protobuf::rt::value_size(1, self.base_rev_id, ::protobuf::wire_format::WireTypeVarint);
+        }
+        if self.rev_id != 0 {
+            my_size += ::protobuf::rt::value_size(2, self.rev_id, ::protobuf::wire_format::WireTypeVarint);
+        }
+        if !self.delta.is_empty() {
+            my_size += ::protobuf::rt::bytes_size(3, &self.delta);
+        }
+        if !self.md5.is_empty() {
+            my_size += ::protobuf::rt::string_size(4, &self.md5);
+        }
+        my_size += ::protobuf::rt::unknown_fields_size(self.get_unknown_fields());
+        self.cached_size.set(my_size);
+        my_size
+    }
+
+    fn write_to_with_cached_sizes(&self, os: &mut ::protobuf::CodedOutputStream<'_>) -> ::protobuf::ProtobufResult<()> {
+        if self.base_rev_id != 0 {
+            os.write_int64(1, self.base_rev_id)?;
+        }
+        if self.rev_id != 0 {
+            os.write_int64(2, self.rev_id)?;
+        }
+        if !self.delta.is_empty() {
+            os.write_bytes(3, &self.delta)?;
+        }
+        if !self.md5.is_empty() {
+            os.write_string(4, &self.md5)?;
+        }
+        os.write_unknown_fields(self.get_unknown_fields())?;
+        ::std::result::Result::Ok(())
+    }
+
+    fn get_cached_size(&self) -> u32 {
+        self.cached_size.get()
+    }
+
+    fn get_unknown_fields(&self) -> &::protobuf::UnknownFields {
+        &self.unknown_fields
+    }
+
+    fn mut_unknown_fields(&mut self) -> &mut ::protobuf::UnknownFields {
+        &mut self.unknown_fields
+    }
+
+    fn as_any(&self) -> &dyn (::std::any::Any) {
+        self as &dyn (::std::any::Any)
+    }
+    fn as_any_mut(&mut self) -> &mut dyn (::std::any::Any) {
+        self as &mut dyn (::std::any::Any)
+    }
+    fn into_any(self: ::std::boxed::Box<Self>) -> ::std::boxed::Box<dyn (::std::any::Any)> {
+        self
+    }
+
+    fn descriptor(&self) -> &'static ::protobuf::reflect::MessageDescriptor {
+        Self::descriptor_static()
+    }
+
+    fn new() -> Revision {
+        Revision::new()
+    }
+
+    fn descriptor_static() -> &'static ::protobuf::reflect::MessageDescriptor {
+        static descriptor: ::protobuf::rt::LazyV2<::protobuf::reflect::MessageDescriptor> = ::protobuf::rt::LazyV2::INIT;
+        descriptor.get(|| {
+            let mut fields = ::std::vec::Vec::new();
+            fields.push(::protobuf::reflect::accessor::make_simple_field_accessor::<_, ::protobuf::types::ProtobufTypeInt64>(
+                "base_rev_id",
+                |m: &Revision| { &m.base_rev_id },
+                |m: &mut Revision| { &mut m.base_rev_id },
+            ));
+            fields.push(::protobuf::reflect::accessor::make_simple_field_accessor::<_, ::protobuf::types::ProtobufTypeInt64>(
+                "rev_id",
+                |m: &Revision| { &m.rev_id },
+                |m: &mut Revision| { &mut m.rev_id },
+            ));
+            fields.push(::protobuf::reflect::accessor::make_simple_field_accessor::<_, ::protobuf::types::ProtobufTypeBytes>(
+                "delta",
+                |m: &Revision| { &m.delta },
+                |m: &mut Revision| { &mut m.delta },
+            ));
+            fields.push(::protobuf::reflect::accessor::make_simple_field_accessor::<_, ::protobuf::types::ProtobufTypeString>(
+                "md5",
+                |m: &Revision| { &m.md5 },
+                |m: &mut Revision| { &mut m.md5 },
+            ));
+            ::protobuf::reflect::MessageDescriptor::new_pb_name::<Revision>(
+                "Revision",
+                fields,
+                file_descriptor_proto()
+            )
+        })
+    }
+
+    fn default_instance() -> &'static Revision {
+        static instance: ::protobuf::rt::LazyV2<Revision> = ::protobuf::rt::LazyV2::INIT;
+        instance.get(Revision::new)
+    }
+}
+
+impl ::protobuf::Clear for Revision {
+    fn clear(&mut self) {
+        self.base_rev_id = 0;
+        self.rev_id = 0;
+        self.delta.clear();
+        self.md5.clear();
+        self.unknown_fields.clear();
+    }
+}
+
+impl ::std::fmt::Debug for Revision {
+    fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
+        ::protobuf::text_format::fmt(self, f)
+    }
+}
+
+impl ::protobuf::reflect::ProtobufValue for Revision {
+    fn as_ref(&self) -> ::protobuf::reflect::ReflectValueRef {
+        ::protobuf::reflect::ReflectValueRef::Message(self)
+    }
+}
+
+static file_descriptor_proto_data: &'static [u8] = b"\
+    \n\x0erevision.proto\"i\n\x08Revision\x12\x1e\n\x0bbase_rev_id\x18\x01\
+    \x20\x01(\x03R\tbaseRevId\x12\x15\n\x06rev_id\x18\x02\x20\x01(\x03R\x05r\
+    evId\x12\x14\n\x05delta\x18\x03\x20\x01(\x0cR\x05delta\x12\x10\n\x03md5\
+    \x18\x04\x20\x01(\tR\x03md5J\x86\x02\n\x06\x12\x04\0\0\x06\x01\n\x08\n\
+    \x01\x0c\x12\x03\0\0\x12\n\n\n\x02\x04\0\x12\x04\x01\0\x06\x01\n\n\n\x03\
+    \x04\0\x01\x12\x03\x01\x08\x10\n\x0b\n\x04\x04\0\x02\0\x12\x03\x02\x04\
+    \x1a\n\x0c\n\x05\x04\0\x02\0\x05\x12\x03\x02\x04\t\n\x0c\n\x05\x04\0\x02\
+    \0\x01\x12\x03\x02\n\x15\n\x0c\n\x05\x04\0\x02\0\x03\x12\x03\x02\x18\x19\
+    \n\x0b\n\x04\x04\0\x02\x01\x12\x03\x03\x04\x15\n\x0c\n\x05\x04\0\x02\x01\
+    \x05\x12\x03\x03\x04\t\n\x0c\n\x05\x04\0\x02\x01\x01\x12\x03\x03\n\x10\n\
+    \x0c\n\x05\x04\0\x02\x01\x03\x12\x03\x03\x13\x14\n\x0b\n\x04\x04\0\x02\
+    \x02\x12\x03\x04\x04\x14\n\x0c\n\x05\x04\0\x02\x02\x05\x12\x03\x04\x04\t\
+    \n\x0c\n\x05\x04\0\x02\x02\x01\x12\x03\x04\n\x0f\n\x0c\n\x05\x04\0\x02\
+    \x02\x03\x12\x03\x04\x12\x13\n\x0b\n\x04\x04\0\x02\x03\x12\x03\x05\x04\
+    \x13\n\x0c\n\x05\x04\0\x02\x03\x05\x12\x03\x05\x04\n\n\x0c\n\x05\x04\0\
+    \x02\x03\x01\x12\x03\x05\x0b\x0e\n\x0c\n\x05\x04\0\x02\x03\x03\x12\x03\
+    \x05\x11\x12b\x06proto3\
+";
+
+static file_descriptor_proto_lazy: ::protobuf::rt::LazyV2<::protobuf::descriptor::FileDescriptorProto> = ::protobuf::rt::LazyV2::INIT;
+
+fn parse_descriptor_proto() -> ::protobuf::descriptor::FileDescriptorProto {
+    ::protobuf::Message::parse_from_bytes(file_descriptor_proto_data).unwrap()
+}
+
+pub fn file_descriptor_proto() -> &'static ::protobuf::descriptor::FileDescriptorProto {
+    file_descriptor_proto_lazy.get(|| {
+        parse_descriptor_proto()
+    })
+}
diff --git a/rust-lib/flowy-document/src/protobuf/proto/revision.proto b/rust-lib/flowy-document/src/protobuf/proto/revision.proto
new file mode 100644
index 0000000000..1b88b1bf0d
--- /dev/null
+++ b/rust-lib/flowy-document/src/protobuf/proto/revision.proto
@@ -0,0 +1,7 @@
+syntax = "proto3";
+message Revision {
+    int64 base_rev_id = 1;
+    int64 rev_id = 2;
+    bytes delta = 3;
+    string md5 = 4;
+}
diff --git a/rust-lib/flowy-document/src/services/cache.rs b/rust-lib/flowy-document/src/services/cache.rs
index 84df313353..abf5abb612 100644
--- a/rust-lib/flowy-document/src/services/cache.rs
+++ b/rust-lib/flowy-document/src/services/cache.rs
@@ -1,19 +1,10 @@
-use std::{convert::TryInto, fmt::Debug, sync::Arc};
+use std::sync::Arc;
 
-use bytes::Bytes;
 use dashmap::DashMap;
-use parking_lot::RwLock;
-
-use flowy_database::ConnectionPool;
-use flowy_ot::{core::Delta, errors::OTError};
 
 use crate::{
-    entities::doc::Doc,
     errors::DocError,
-    services::{
-        doc::edit_context::{DocId, EditDocContext},
-        ws::WsManager,
-    },
+    services::doc::edit_context::{DocId, EditDocContext},
 };
 
 pub(crate) struct DocCache {
diff --git a/rust-lib/flowy-document/src/services/doc/doc_controller.rs b/rust-lib/flowy-document/src/services/doc/doc_controller.rs
index d41e58bedc..e87aacef8a 100644
--- a/rust-lib/flowy-document/src/services/doc/doc_controller.rs
+++ b/rust-lib/flowy-document/src/services/doc/doc_controller.rs
@@ -2,19 +2,15 @@ use crate::{
     entities::doc::{CreateDocParams, Doc, DocDelta, QueryDocParams, UpdateDocParams},
     errors::{internal_error, DocError},
     module::DocumentUser,
-    services::{
-        cache::DocCache,
-        doc::edit_context::{DocId, EditDocContext, EditDocPersistence},
-        server::Server,
-        ws::WsManager,
-    },
-    sql_tables::doc::{DocTable, DocTableChangeset, DocTableSql, OpTableSql},
+    services::{cache::DocCache, doc::edit_context::EditDocContext, server::Server, ws::WsManager},
+    sql_tables::doc::{DocTable, DocTableSql, OpTableSql},
 };
 use bytes::Bytes;
 use flowy_database::{ConnectionPool, SqliteConnection};
+use flowy_infra::future::ClosureFuture;
+
 use parking_lot::RwLock;
 use std::sync::Arc;
-use tokio::task::JoinHandle;
 
 pub(crate) struct DocController {
     server: Server,
@@ -107,29 +103,17 @@ impl DocController {
     }
 
     #[tracing::instrument(level = "debug", skip(self, pool), err)]
-    fn read_doc_from_server(
-        &self,
-        params: QueryDocParams,
-        pool: Arc<ConnectionPool>,
-    ) -> Result<JoinHandle<Result<Arc<EditDocContext>, DocError>>, DocError> {
+    async fn read_doc_from_server(&self, params: QueryDocParams, pool: Arc<ConnectionPool>) -> Result<Arc<EditDocContext>, DocError> {
         let token = self.user.token()?;
-        let server = self.server.clone();
-        let doc_sql = self.doc_sql.clone();
-        let op_sql = self.op_sql.clone();
-        let ws = self.ws.clone();
-        let cache = self.cache.clone();
-
-        Ok(tokio::spawn(async move {
-            match server.read_doc(&token, params).await? {
-                None => Err(DocError::not_found()),
-                Some(doc) => {
-                    let doc_table = DocTable::new(doc.clone());
-                    let _ = doc_sql.create_doc_table(doc_table, &*(pool.get().map_err(internal_error)?))?;
-                    let edit_doc_ctx = make_edit_context(ws, cache, op_sql, doc)?;
-                    Ok(edit_doc_ctx)
-                },
-            }
-        }))
+        match self.server.read_doc(&token, params).await? {
+            None => Err(DocError::not_found()),
+            Some(doc) => {
+                let edit = self.make_edit_context(doc.clone())?;
+                let conn = &*(pool.get().map_err(internal_error)?);
+                let _ = self.doc_sql.create_doc_table(doc.into(), conn)?;
+                Ok(edit)
+            },
+        }
     }
 
     #[tracing::instrument(level = "debug", skip(self), err)]
@@ -149,44 +133,26 @@ impl DocController {
     }
 
     async fn _open(&self, params: QueryDocParams, pool: Arc<ConnectionPool>) -> Result<Arc<EditDocContext>, DocError> {
-        match self.doc_sql.read_doc_table(&params.doc_id, &*(pool.get().map_err(internal_error)?)) {
-            Ok(doc_table) => {
-                let edit_doc_ctx = make_edit_context(self.ws.clone(), self.cache.clone(), self.op_sql.clone(), doc_table.into())?;
-                Ok(edit_doc_ctx)
-            },
+        match self.doc_sql.read_doc_table(&params.doc_id, pool.clone()) {
+            Ok(doc_table) => Ok(self.make_edit_context(doc_table.into())?),
             Err(error) => {
                 if error.is_record_not_found() {
                     log::debug!("Doc:{} don't exist, reading from server", params.doc_id);
-                    match self.read_doc_from_server(params, pool)?.await.map_err(internal_error)? {
-                        Ok(edit_doc_ctx) => Ok(edit_doc_ctx),
-                        Err(error) => Err(error),
-                    }
+                    Ok(self.read_doc_from_server(params, pool.clone()).await?)
                 } else {
                     return Err(error);
                 }
             },
         }
     }
-}
 
-fn make_edit_context(
-    ws: Arc<RwLock<WsManager>>,
-    cache: Arc<DocCache>,
-    op_sql: Arc<OpTableSql>,
-    doc: Doc,
-) -> Result<Arc<EditDocContext>, DocError> {
-    // Opti: require upgradable_read lock and then upgrade to write lock using
-    // RwLockUpgradableReadGuard::upgrade(xx)
-    let edit_doc_ctx = Arc::new(EditDocContext::new(doc, ws.read().sender.clone(), op_sql)?);
-    ws.write().register_handler(edit_doc_ctx.id.as_ref(), edit_doc_ctx.clone());
-    cache.set(edit_doc_ctx.clone());
-    Ok(edit_doc_ctx)
-}
-
-impl EditDocPersistence for DocController {
-    fn save(&self, params: UpdateDocParams, pool: Arc<ConnectionPool>) -> Result<(), DocError> {
-        let changeset = DocTableChangeset::new(params.clone());
-        let _ = self.doc_sql.update_doc_table(changeset, &*(pool.get().map_err(internal_error)?))?;
-        Ok(())
+    fn make_edit_context(&self, doc: Doc) -> Result<Arc<EditDocContext>, DocError> {
+        // Opti: require upgradable_read lock and then upgrade to write lock using
+        // RwLockUpgradableReadGuard::upgrade(xx) of ws
+        let sender = self.ws.read().sender.clone();
+        let edit_ctx = Arc::new(EditDocContext::new(doc, sender, self.op_sql.clone())?);
+        self.ws.write().register_handler(edit_ctx.id.as_ref(), edit_ctx.clone());
+        self.cache.set(edit_ctx.clone());
+        Ok(edit_ctx)
     }
 }
diff --git a/rust-lib/flowy-document/src/services/doc/document/document.rs b/rust-lib/flowy-document/src/services/doc/document/document.rs
index 081ed43bc5..4d64a53c46 100644
--- a/rust-lib/flowy-document/src/services/doc/document/document.rs
+++ b/rust-lib/flowy-document/src/services/doc/document/document.rs
@@ -4,7 +4,6 @@ use crate::{
 };
 use bytes::Bytes;
 use flowy_ot::core::*;
-use std::convert::TryInto;
 
 pub trait DocumentData {
     fn into_string(self) -> Result<String, DocError>;
@@ -24,24 +23,10 @@ impl CustomDocument for FlowyDoc {
     fn init_delta() -> Delta { DeltaBuilder::new().insert("\n").build() }
 }
 
-#[derive(Debug, Clone)]
-pub struct RevId(pub usize);
-
-#[derive(Debug, Clone)]
-pub struct Revision {
-    rev_id: RevId,
-    pub delta: Delta,
-}
-
-impl Revision {
-    pub fn new(rev_id: RevId, delta: Delta) -> Revision { Self { rev_id, delta } }
-}
-
 pub struct Document {
     delta: Delta,
     history: History,
     view: View,
-    rev_id_counter: usize,
     last_edit_time: usize,
 }
 
@@ -53,7 +38,6 @@ impl Document {
             delta,
             history: History::new(),
             view: View::new(),
-            rev_id_counter: 1,
             last_edit_time: 0,
         }
     }
@@ -67,16 +51,11 @@ impl Document {
 
     pub fn to_bytes(&self) -> Vec<u8> { self.delta.clone().into_bytes() }
 
-    pub fn to_string(&self) -> String { self.delta.apply("").unwrap() }
+    pub fn to_plain_string(&self) -> String { self.delta.apply("").unwrap() }
 
     pub fn apply_delta(&mut self, data: Bytes) -> Result<(), DocError> {
         let new_delta = Delta::from_bytes(data.to_vec())?;
-
         log::debug!("Apply delta: {}", new_delta);
-
-        let rev_id = self.next_rev_id();
-        let revision = Revision::new(rev_id, new_delta.clone());
-
         let _ = self.add_delta(&new_delta)?;
         log::debug!("Document: {}", self.to_json());
         Ok(())
@@ -173,7 +152,6 @@ impl Document {
     fn add_delta(&mut self, delta: &Delta) -> Result<(), DocError> {
         let composed_delta = self.delta.compose(delta)?;
         let mut undo_delta = delta.invert(&self.delta);
-        self.rev_id_counter += 1;
 
         let now = chrono::Utc::now().timestamp_millis() as usize;
         if now - self.last_edit_time < RECORD_THRESHOLD {
@@ -206,9 +184,6 @@ impl Document {
         let inverted_delta = change.invert(&self.delta);
         Ok((new_delta, inverted_delta))
     }
-
-    #[allow(dead_code)]
-    fn next_rev_id(&self) -> RevId { RevId(self.rev_id_counter) }
 }
 
 fn validate_interval(delta: &Delta, interval: &Interval) -> Result<(), DocError> {
diff --git a/rust-lib/flowy-document/src/services/doc/edit_context.rs b/rust-lib/flowy-document/src/services/doc/edit_context.rs
index 617b1d2d53..b14d5e02e5 100644
--- a/rust-lib/flowy-document/src/services/doc/edit_context.rs
+++ b/rust-lib/flowy-document/src/services/doc/edit_context.rs
@@ -1,40 +1,30 @@
 use crate::{
     entities::{
-        doc::{Doc, UpdateDocParams},
+        doc::{Doc, Revision},
         ws::{WsDocumentData, WsSource},
     },
-    errors::DocError,
+    errors::{internal_error, DocError},
     services::{
         doc::Document,
         ws::{WsHandler, WsSender},
     },
-    sql_tables::doc::OpTableSql,
+    sql_tables::doc::{OpState, OpTable, OpTableSql},
 };
 use bytes::Bytes;
 use flowy_database::ConnectionPool;
 use flowy_ot::core::Delta;
-use parking_lot::RwLock;
-use std::{convert::TryInto, sync::Arc};
-
-#[derive(Debug, Clone, Eq, PartialEq, Hash)]
-pub struct DocId(pub(crate) String);
-impl AsRef<str> for DocId {
-    fn as_ref(&self) -> &str { &self.0 }
-}
-impl<T> std::convert::From<T> for DocId
-where
-    T: ToString,
-{
-    fn from(s: T) -> Self { DocId(s.to_string()) }
-}
-
-pub(crate) trait EditDocPersistence: Send + Sync {
-    fn save(&self, params: UpdateDocParams, pool: Arc<ConnectionPool>) -> Result<(), DocError>;
-}
+use parking_lot::{lock_api::RwLockWriteGuard, RawRwLock, RwLock};
+use std::{
+    convert::TryInto,
+    sync::{
+        atomic::{AtomicI64, AtomicUsize, Ordering::SeqCst},
+        Arc,
+    },
+};
 
 pub(crate) struct EditDocContext {
     pub(crate) id: DocId,
-    pub(crate) revision: i64,
+    pub(crate) rev_counter: RevCounter,
     document: RwLock<Document>,
     ws_sender: Arc<dyn WsSender>,
     op_sql: Arc<OpTableSql>,
@@ -43,13 +33,13 @@ pub(crate) struct EditDocContext {
 impl EditDocContext {
     pub(crate) fn new(doc: Doc, ws_sender: Arc<dyn WsSender>, op_sql: Arc<OpTableSql>) -> Result<Self, DocError> {
         let id: DocId = doc.id.into();
-        let revision = doc.revision;
+        let rev_counter = RevCounter::new(doc.revision);
         let delta: Delta = doc.data.try_into()?;
         let document = RwLock::new(Document::from_delta(delta));
 
         Ok(Self {
             id,
-            revision,
+            rev_counter,
             document,
             ws_sender,
             op_sql,
@@ -58,33 +48,57 @@ impl EditDocContext {
 
     pub(crate) fn doc(&self) -> Doc {
         Doc {
-            id: self.id.0.clone(),
+            id: self.id.clone().into(),
             data: self.document.read().to_bytes(),
-            revision: self.revision,
+            revision: self.rev_counter.value(),
         }
     }
 
     pub(crate) fn apply_delta(&self, data: Bytes, pool: Arc<ConnectionPool>) -> Result<(), DocError> {
-        let mut write_guard = self.document.write();
-        let _ = write_guard.apply_delta(data.clone())?;
+        let mut guard = self.document.write();
+        let base_rev_id = self.rev_counter.value();
+        let rev_id = self.rev_counter.next();
+        let _ = guard.apply_delta(data.clone())?;
+        let json = guard.to_json();
+        drop(guard);
 
-        match self.ws_sender.send_data(data) {
-            Ok(_) => {},
+        // Opti: it is necessary to save the rev if send success?
+        let md5 = format!("{:x}", md5::compute(json));
+        let revision = Revision::new(base_rev_id, rev_id, data.to_vec(), md5);
+        self.save_revision(revision.clone(), pool.clone());
+        match self.ws_sender.send_data(revision.try_into()?) {
+            Ok(_) => {
+                // TODO: remove the rev if send success
+                // let _ = self.delete_revision(rev_id, pool)?;
+            },
             Err(e) => {
-                // TODO: save to local and retry
                 log::error!("Send delta failed: {:?}", e);
             },
         }
+        Ok(())
+    }
+}
 
-        // Opti: strategy to save the document
-        let save = UpdateDocParams {
-            doc_id: self.id.0.clone(),
-            data: write_guard.to_bytes(),
-        };
-        // let _ = self.persistence.save(save, pool)?;
+impl EditDocContext {
+    fn save_revision(&self, revision: Revision, pool: Arc<ConnectionPool>) -> Result<(), DocError> {
+        let conn = &*pool.get().map_err(internal_error)?;
+        conn.immediate_transaction::<_, DocError, _>(|| {
+            let op_table: OpTable = revision.into();
+            let _ = self.op_sql.create_op_table(op_table, conn)?;
+            Ok(())
+        })?;
 
         Ok(())
     }
+
+    fn delete_revision(&self, rev_id: i64, pool: Arc<ConnectionPool>) -> Result<(), DocError> {
+        let conn = &*pool.get().map_err(internal_error)?;
+        conn.immediate_transaction::<_, DocError, _>(|| {
+            let _ = self.op_sql.delete_op_table(rev_id, conn)?;
+            Ok(())
+        })?;
+        Ok(())
+    }
 }
 
 impl WsHandler for EditDocContext {
@@ -94,3 +108,33 @@ impl WsHandler for EditDocContext {
         }
     }
 }
+
+#[derive(Debug, Clone, Eq, PartialEq, Hash)]
+pub struct DocId(pub(crate) String);
+
+impl AsRef<str> for DocId {
+    fn as_ref(&self) -> &str { &self.0 }
+}
+
+impl<T> std::convert::From<T> for DocId
+where
+    T: ToString,
+{
+    fn from(s: T) -> Self { DocId(s.to_string()) }
+}
+
+impl std::convert::Into<String> for DocId {
+    fn into(self) -> String { self.0.clone() }
+}
+
+#[derive(Debug)]
+pub struct RevCounter(pub AtomicI64);
+
+impl RevCounter {
+    pub fn new(n: i64) -> Self { Self(AtomicI64::new(n)) }
+    pub fn next(&self) -> i64 {
+        let _ = self.0.fetch_add(1, SeqCst);
+        self.value()
+    }
+    pub fn value(&self) -> i64 { self.0.load(SeqCst) }
+}
diff --git a/rust-lib/flowy-document/src/sql_tables/doc/doc_op_sql.rs b/rust-lib/flowy-document/src/sql_tables/doc/doc_op_sql.rs
index de0876b365..312714ef6f 100644
--- a/rust-lib/flowy-document/src/sql_tables/doc/doc_op_sql.rs
+++ b/rust-lib/flowy-document/src/sql_tables/doc/doc_op_sql.rs
@@ -17,7 +17,7 @@ impl OpTableSql {
     }
 
     pub(crate) fn update_op_table(&self, changeset: OpChangeset, conn: &SqliteConnection) -> Result<(), DocError> {
-        let filter = dsl::op_table.filter(op_table::dsl::rev.eq(changeset.rev));
+        let filter = dsl::op_table.filter(op_table::dsl::rev_id.eq(changeset.rev_id));
         let affected_row = diesel::update(filter).set(changeset).execute(conn)?;
         debug_assert_eq!(affected_row, 1);
         Ok(())
@@ -28,8 +28,8 @@ impl OpTableSql {
         Ok(ops)
     }
 
-    pub(crate) fn delete_op_table(&self, rev: i64, conn: &SqliteConnection) -> Result<(), DocError> {
-        let filter = dsl::op_table.filter(op_table::dsl::rev.eq(rev));
+    pub(crate) fn delete_op_table(&self, rev_id: i64, conn: &SqliteConnection) -> Result<(), DocError> {
+        let filter = dsl::op_table.filter(op_table::dsl::rev_id.eq(rev_id));
         let affected_row = diesel::delete(filter).execute(conn)?;
         debug_assert_eq!(affected_row, 1);
         Ok(())
diff --git a/rust-lib/flowy-document/src/sql_tables/doc/doc_op_table.rs b/rust-lib/flowy-document/src/sql_tables/doc/doc_op_table.rs
index b8888f04e7..0f8fb89a7e 100644
--- a/rust-lib/flowy-document/src/sql_tables/doc/doc_op_table.rs
+++ b/rust-lib/flowy-document/src/sql_tables/doc/doc_op_table.rs
@@ -1,12 +1,13 @@
+use crate::entities::doc::Revision;
 use diesel::sql_types::Integer;
 use flowy_database::schema::op_table;
 
 #[derive(PartialEq, Clone, Debug, Queryable, Identifiable, Insertable, Associations)]
 #[table_name = "op_table"]
-#[primary_key(rev)]
+#[primary_key(rev_id)]
 pub(crate) struct OpTable {
-    pub(crate) base_rev: i64,
-    pub(crate) rev: i64,
+    pub(crate) base_rev_id: i64,
+    pub(crate) rev_id: i64,
     pub(crate) data: Vec<u8>,
     pub(crate) md5: String,
     pub(crate) state: OpState,
@@ -47,8 +48,20 @@ impl_sql_integer_expression!(OpState);
 
 #[derive(AsChangeset, Identifiable, Default, Debug)]
 #[table_name = "op_table"]
-#[primary_key(rev)]
+#[primary_key(rev_id)]
 pub(crate) struct OpChangeset {
-    pub(crate) rev: i64,
+    pub(crate) rev_id: i64,
     pub(crate) state: Option<OpState>,
 }
+
+impl std::convert::Into<OpTable> for Revision {
+    fn into(self) -> OpTable {
+        OpTable {
+            base_rev_id: self.base_rev_id,
+            rev_id: self.rev_id,
+            data: self.delta,
+            md5: self.md5,
+            state: OpState::Local,
+        }
+    }
+}
diff --git a/rust-lib/flowy-document/src/sql_tables/doc/doc_sql.rs b/rust-lib/flowy-document/src/sql_tables/doc/doc_sql.rs
index 9e7f57e43e..a0d5077c24 100644
--- a/rust-lib/flowy-document/src/sql_tables/doc/doc_sql.rs
+++ b/rust-lib/flowy-document/src/sql_tables/doc/doc_sql.rs
@@ -1,12 +1,14 @@
 use crate::{
-    errors::DocError,
+    errors::{internal_error, DocError},
     sql_tables::doc::{DocTable, DocTableChangeset},
 };
 use flowy_database::{
     prelude::*,
     schema::{doc_table, doc_table::dsl},
+    ConnectionPool,
     SqliteConnection,
 };
+use std::sync::Arc;
 
 pub struct DocTableSql {}
 
@@ -21,7 +23,8 @@ impl DocTableSql {
         Ok(())
     }
 
-    pub(crate) fn read_doc_table(&self, doc_id: &str, conn: &SqliteConnection) -> Result<DocTable, DocError> {
+    pub(crate) fn read_doc_table(&self, doc_id: &str, pool: Arc<ConnectionPool>) -> Result<DocTable, DocError> {
+        let conn = &*pool.get().map_err(internal_error)?;
         let doc_table = dsl::doc_table.filter(doc_table::id.eq(doc_id)).first::<DocTable>(conn)?;
 
         Ok(doc_table)
diff --git a/rust-lib/flowy-document/src/sql_tables/doc/doc_table.rs b/rust-lib/flowy-document/src/sql_tables/doc/doc_table.rs
index ce4ea2daa8..b465536d9a 100644
--- a/rust-lib/flowy-document/src/sql_tables/doc/doc_table.rs
+++ b/rust-lib/flowy-document/src/sql_tables/doc/doc_table.rs
@@ -44,3 +44,13 @@ impl std::convert::Into<Doc> for DocTable {
         }
     }
 }
+
+impl std::convert::From<Doc> for DocTable {
+    fn from(doc: Doc) -> Self {
+        Self {
+            id: doc.id,
+            data: doc.data,
+            revision: doc.revision,
+        }
+    }
+}
diff --git a/rust-lib/flowy-document/tests/editor/mod.rs b/rust-lib/flowy-document/tests/editor/mod.rs
index d8ff30d1c6..5891d0e884 100644
--- a/rust-lib/flowy-document/tests/editor/mod.rs
+++ b/rust-lib/flowy-document/tests/editor/mod.rs
@@ -174,7 +174,7 @@ impl TestBuilder {
                 std::thread::sleep(Duration::from_millis(*mills_sec as u64));
             },
             TestOp::AssertStr(delta_i, expected) => {
-                assert_eq!(&self.documents[*delta_i].to_string(), expected);
+                assert_eq!(&self.documents[*delta_i].to_plain_string(), expected);
             },
 
             TestOp::AssertOpsJson(delta_i, expected) => {
@@ -199,10 +199,6 @@ impl TestBuilder {
     }
 }
 
-pub fn debug_print_delta(delta: &Delta) {
-    eprintln!("😁 {}", serde_json::to_string(delta).unwrap());
-}
-
 pub struct Rng(StdRng);
 
 impl Default for Rng {
@@ -210,6 +206,7 @@ impl Default for Rng {
 }
 
 impl Rng {
+    #[allow(dead_code)]
     pub fn from_seed(seed: [u8; 32]) -> Self { Rng(StdRng::from_seed(seed)) }
 
     pub fn gen_string(&mut self, len: usize) -> String { (0..len).map(|_| self.0.gen::<char>()).collect() }
diff --git a/rust-lib/flowy-infra/src/future.rs b/rust-lib/flowy-infra/src/future.rs
index 73778ffa26..63363b102d 100644
--- a/rust-lib/flowy-infra/src/future.rs
+++ b/rust-lib/flowy-infra/src/future.rs
@@ -8,12 +8,12 @@ use std::{
 };
 
 #[pin_project]
-pub struct RequestFuture<T> {
+pub struct ClosureFuture<T> {
     #[pin]
     pub fut: Pin<Box<dyn Future<Output = T> + Sync + Send>>,
 }
 
-impl<T> Future for RequestFuture<T>
+impl<T> Future for ClosureFuture<T>
 where
     T: Send + Sync,
 {
diff --git a/rust-lib/flowy-sdk/src/deps_resolve/document_deps.rs b/rust-lib/flowy-sdk/src/deps_resolve/document_deps.rs
index 1015634e2b..ecc97972fe 100644
--- a/rust-lib/flowy-sdk/src/deps_resolve/document_deps.rs
+++ b/rust-lib/flowy-sdk/src/deps_resolve/document_deps.rs
@@ -5,7 +5,7 @@ use flowy_document::{
     prelude::{WsManager, WsSender, WS_ID},
 };
 
-use flowy_user::services::user::UserSession;
+use flowy_user::{errors::ErrorCode, services::user::UserSession};
 use flowy_ws::{WsMessage, WsMessageHandler};
 use parking_lot::RwLock;
 use std::{path::Path, sync::Arc};
@@ -51,9 +51,19 @@ impl DocumentUser for DocumentUserImpl {
         Ok(doc_dir)
     }
 
-    fn user_id(&self) -> Result<String, DocError> { self.user.user_id().map_err(|e| DocError::internal().context(e)) }
+    fn user_id(&self) -> Result<String, DocError> {
+        self.user.user_id().map_err(|e| match e.code {
+            ErrorCode::InternalError => DocError::internal().context(e.msg),
+            _ => DocError::internal().context(e),
+        })
+    }
 
-    fn token(&self) -> Result<String, DocError> { self.user.token().map_err(|e| DocError::internal().context(e)) }
+    fn token(&self) -> Result<String, DocError> {
+        self.user.token().map_err(|e| match e.code {
+            ErrorCode::InternalError => DocError::internal().context(e.msg),
+            _ => DocError::internal().context(e),
+        })
+    }
 }
 
 struct WsSenderImpl {
diff --git a/rust-lib/flowy-sqlite/src/pool.rs b/rust-lib/flowy-sqlite/src/pool.rs
index a4a645249d..8522687b83 100644
--- a/rust-lib/flowy-sqlite/src/pool.rs
+++ b/rust-lib/flowy-sqlite/src/pool.rs
@@ -49,32 +49,6 @@ impl ConnectionPool {
     }
 }
 
-#[derive(Default, Debug, Clone)]
-pub struct ConnCounter(Arc<ConnCounterInner>);
-
-impl std::ops::Deref for ConnCounter {
-    type Target = ConnCounterInner;
-
-    fn deref(&self) -> &Self::Target { &*self.0 }
-}
-
-#[derive(Default, Debug)]
-pub struct ConnCounterInner {
-    max_number: AtomicUsize,
-    current_number: AtomicUsize,
-}
-
-impl ConnCounterInner {
-    pub fn get_max_num(&self) -> usize { self.max_number.load(SeqCst) }
-
-    pub fn reset(&self) {
-        // reset max_number to current_number
-        let _ = self
-            .max_number
-            .fetch_update(SeqCst, SeqCst, |_| Some(self.current_number.load(SeqCst)));
-    }
-}
-
 pub type OnExecFunc = Box<dyn Fn() -> Box<dyn Fn(&SqliteConnection, &str)> + Send + Sync>;
 
 pub struct PoolConfig {
diff --git a/rust-lib/flowy-user/src/errors.rs b/rust-lib/flowy-user/src/errors.rs
index 6686f3101b..2443eef466 100644
--- a/rust-lib/flowy-user/src/errors.rs
+++ b/rust-lib/flowy-user/src/errors.rs
@@ -110,7 +110,12 @@ impl std::convert::From<::r2d2::Error> for UserError {
 }
 
 impl std::convert::From<flowy_ws::errors::WsError> for UserError {
-    fn from(error: flowy_ws::errors::WsError) -> Self { UserError::internal().context(error) }
+    fn from(error: flowy_ws::errors::WsError) -> Self {
+        match error.code {
+            flowy_ws::errors::ErrorCode::InternalError => UserError::internal().context(error.msg),
+            _ => UserError::internal().context(error),
+        }
+    }
 }
 
 // use diesel::result::{Error, DatabaseErrorKind};
diff --git a/rust-lib/flowy-workspace/src/sql_tables/app/app_table.rs b/rust-lib/flowy-workspace/src/sql_tables/app/app_table.rs
index 4e65067f95..cde5d06671 100644
--- a/rust-lib/flowy-workspace/src/sql_tables/app/app_table.rs
+++ b/rust-lib/flowy-workspace/src/sql_tables/app/app_table.rs
@@ -3,7 +3,6 @@ use crate::{
         app::{App, ColorStyle, UpdateAppParams},
         view::RepeatedView,
     },
-    impl_sql_binary_expression,
     sql_tables::workspace::WorkspaceTable,
 };
 use diesel::sql_types::Binary;
diff --git a/rust-lib/flowy-workspace/src/sql_tables/view/view_table.rs b/rust-lib/flowy-workspace/src/sql_tables/view/view_table.rs
index 8aef18a34c..69bea0f907 100644
--- a/rust-lib/flowy-workspace/src/sql_tables/view/view_table.rs
+++ b/rust-lib/flowy-workspace/src/sql_tables/view/view_table.rs
@@ -1,6 +1,5 @@
 use crate::{
     entities::view::{RepeatedView, UpdateViewParams, View, ViewType},
-    impl_sql_integer_expression,
     sql_tables::app::AppTable,
 };
 use diesel::sql_types::Integer;
diff --git a/rust-lib/flowy-ws/src/errors.rs b/rust-lib/flowy-ws/src/errors.rs
index 77bb360cd1..9064dda60f 100644
--- a/rust-lib/flowy-ws/src/errors.rs
+++ b/rust-lib/flowy-ws/src/errors.rs
@@ -8,10 +8,10 @@ use url::ParseError;
 #[derive(Debug, Default, Clone, ProtoBuf)]
 pub struct WsError {
     #[pb(index = 1)]
-    code: ErrorCode,
+    pub code: ErrorCode,
 
     #[pb(index = 2)]
-    msg: String,
+    pub msg: String,
 }
 
 macro_rules! static_user_error {