From adcf40afc33228f8c187adbca83dd0ff41a8e33d Mon Sep 17 00:00:00 2001
From: Christian Kamm <kamm@incasoftware.de>
Date: Wed, 8 Apr 2015 15:30:07 +0200
Subject: [PATCH] Discovery: Speed up initial run. #2796

---
 csync/src/csync.c          | 10 ++--------
 csync/src/csync.h          |  5 -----
 csync/src/csync_private.h  | 12 +++++++++++-
 csync/src/csync_statedb.c  |  8 ++++----
 csync/src/csync_update.c   |  2 +-
 src/libsync/syncengine.cpp |  8 ++++++--
 6 files changed, 24 insertions(+), 21 deletions(-)

diff --git a/csync/src/csync.c b/csync/src/csync.c
index 2390eaae8..65a0655af 100644
--- a/csync/src/csync.c
+++ b/csync/src/csync.c
@@ -576,7 +576,8 @@ int csync_commit(CSYNC *ctx) {
   _csync_clean_ctx(ctx);
 
   ctx->remote.read_from_db = 0;
-  ctx->read_from_db_disabled = 0;
+  ctx->read_remote_from_db = true;
+  ctx->db_is_empty = false;
 
 
   /* Create new trees */
@@ -773,10 +774,3 @@ int csync_set_module_property(CSYNC* ctx, const char* key, void* value)
 #endif
 }
 
-
-int csync_set_read_from_db(CSYNC* ctx, int enabled)
-{
-    ctx->read_from_db_disabled = !enabled;
-    return 0;
-}
-
diff --git a/csync/src/csync.h b/csync/src/csync.h
index 85a4bfb96..f227c7875 100644
--- a/csync/src/csync.h
+++ b/csync/src/csync.h
@@ -550,11 +550,6 @@ void csync_resume(CSYNC *ctx);
  */
 int  csync_abort_requested(CSYNC *ctx);
 
-/**
- * Specify if it is allowed to read the remote tree from the DB (default to enabled)
- */
-int csync_set_read_from_db(CSYNC* ctx, int enabled);
-
 char *csync_normalize_etag(const char *);
 time_t oc_httpdate_parse( const char *date );
 
diff --git a/csync/src/csync_private.h b/csync/src/csync_private.h
index 7a4e2a5eb..8552bf38c 100644
--- a/csync/src/csync_private.h
+++ b/csync/src/csync_private.h
@@ -151,7 +151,17 @@ struct csync_s {
   int status;
   volatile int abort;
   void *rename_info;
-  int  read_from_db_disabled;
+
+  /**
+   * Specify if it is allowed to read the remote tree from the DB (default to enabled)
+   */
+  bool read_remote_from_db;
+
+  /**
+   * If true, the DB is considered empty and all reads are skipped. (default is false)
+   * This is useful during the initial local discovery as it speeds it up significantly.
+   */
+  bool db_is_empty;
 
   struct csync_owncloud_ctx_s *owncloud_context;
 
diff --git a/csync/src/csync_statedb.c b/csync/src/csync_statedb.c
index 1f82e8c3e..1ba406f34 100644
--- a/csync/src/csync_statedb.c
+++ b/csync/src/csync_statedb.c
@@ -298,7 +298,7 @@ csync_file_stat_t *csync_statedb_get_stat_by_hash(CSYNC *ctx,
   csync_file_stat_t *st = NULL;
   int rc;
 
-  if( !ctx ) {
+  if( !ctx || ctx->db_is_empty ) {
       return NULL;
   }
 
@@ -341,7 +341,7 @@ csync_file_stat_t *csync_statedb_get_stat_by_file_id(CSYNC *ctx,
         return 0;
     }
 
-    if( !ctx ) {
+    if( !ctx || ctx->db_is_empty ) {
         return NULL;
     }
 
@@ -381,7 +381,7 @@ csync_file_stat_t *csync_statedb_get_stat_by_inode(CSYNC *ctx,
       return NULL;
   }
 
-  if( !ctx ) {
+  if( !ctx || ctx->db_is_empty ) {
       return NULL;
   }
 
@@ -448,7 +448,7 @@ int csync_statedb_get_below_path( CSYNC *ctx, const char *path ) {
         return -1;
     }
 
-    if( !ctx ) {
+    if( !ctx || ctx->db_is_empty ) {
         return -1;
     }
 
diff --git a/csync/src/csync_update.c b/csync/src/csync_update.c
index fdb6df911..1c89a87ec 100644
--- a/csync/src/csync_update.c
+++ b/csync/src/csync_update.c
@@ -306,7 +306,7 @@ static int _csync_detect_update(CSYNC *ctx, const char *file,
                                                             || !c_streq(fs->remotePerm, tmp->remotePerm)))
                              || (ctx->current == LOCAL_REPLICA && fs->inode != tmp->inode);
         if (type == CSYNC_FTW_TYPE_DIR && ctx->current == REMOTE_REPLICA
-                && !metadata_differ && !ctx->read_from_db_disabled) {
+                && !metadata_differ && ctx->read_remote_from_db) {
             /* If both etag and file id are equal for a directory, read all contents from
              * the database.
              * The metadata comparison ensure that we fetch all the file id or permission when
diff --git a/src/libsync/syncengine.cpp b/src/libsync/syncengine.cpp
index b9ef9c45c..d8fa74a89 100644
--- a/src/libsync/syncengine.cpp
+++ b/src/libsync/syncengine.cpp
@@ -608,11 +608,15 @@ void SyncEngine::startSync()
     if (fileRecordCount >= 1 && isUpdateFrom_1_5) {
         qDebug() << "detected update from 1.5" << fileRecordCount << isUpdateFrom_1_5;
         // Disable the read from DB to be sure to re-read all the fileid and etags.
-        csync_set_read_from_db(_csync_ctx, false);
+        _csync_ctx->read_remote_from_db = false;
     } else {
-        csync_set_read_from_db(_csync_ctx, true);
+        _csync_ctx->read_remote_from_db = true;
     }
 
+    // This tells csync to never read from the DB if it is empty
+    // thereby speeding up the initial discovery significantly.
+    _csync_ctx->db_is_empty = (fileRecordCount == 0);
+
     bool usingSelectiveSync = (!_selectiveSyncBlackList.isEmpty());
     qDebug() << (usingSelectiveSync ? "====Using Selective Sync" : "====NOT Using Selective Sync");
     if (fileRecordCount >= 0 && fileRecordCount < 50 && !usingSelectiveSync) {
-- 
2.30.2