diff --git a/src/Archive.cc b/src/Archive.cc
index 59136f4f..d4311d5e 100644
--- a/src/Archive.cc
+++ b/src/Archive.cc
@@ -83,7 +83,7 @@ Archive::Archive(ArchiveContentsPtr contents_) :
     name(contents->name),
     filetype(contents->filetype),
     where(contents->where),
-    cache_changed(false),
+    cache_changed(NONE),
     modified(false) {
         changes.resize(files.size());
     }
@@ -197,6 +197,7 @@ bool Archive::file_ensure_hashes(uint64_t idx, size_t detector_id, int hashtypes
 	    f->open();
 	} catch (Exception &e) {
 	    output.error("%s: %s: can't open: %s", name.c_str(), file.name.c_str(), e.what());
+            set_cache_changed(FILES);
 	    file.broken = true;
 	    return false;
 	}
@@ -207,11 +208,13 @@ bool Archive::file_ensure_hashes(uint64_t idx, size_t detector_id, int hashtypes
 
 	case READ_ERROR:
 	    output.error("%s: %s: can't compute hashes: %s", name.c_str(), file.name.c_str(), strerror(errno));
+            set_cache_changed(FILES);
 	    file.broken = true;
 	    return false;
 
 	case CRC_ERROR:
 	    output.error("%s: %s: CRC error: %08x != %08x", name.c_str(), file.name.c_str(), hashes.crc, file.hashes.crc);
+            set_cache_changed(FILES);
 	    file.broken = true;
 	    return false;
 	}
@@ -223,7 +226,8 @@ bool Archive::file_ensure_hashes(uint64_t idx, size_t detector_id, int hashtypes
 	    return false;
 	}
     }
-    cache_changed = true;
+    set_cache_changed(HASHES_ONLY);
+    changes[idx].updated_hashes.insert(detector_id);
 
     return true;
 }
@@ -388,8 +392,8 @@ ArchivePtr Archive::open_toplevel(const std::string &name, filetype_t filetype,
 bool Archive::read_infos() {
     std::vector<File> files_cache;
 
-    cache_changed = false;
-    
+    set_cache_changed(NONE);
+
     contents->read_infos_from_cachedb(&files_cache);
 
     if (contents->cache_id > 0) {
@@ -398,7 +402,7 @@ bool Archive::read_infos() {
                 return false;
                 
             case 0:
-                cache_changed = true;
+                set_cache_changed(FILES);
 		break;
 
 	    case 1:
@@ -413,12 +417,12 @@ bool Archive::read_infos() {
     }
 
     if (!read_infos_xxx()) {
-        cache_changed = true;
+        set_cache_changed(FILES);
 	return false;
     }
 
-    merge_files(files_cache);
     changes.resize(files.size());
+    merge_files(files_cache);
 
     return true;
 }
@@ -493,6 +497,8 @@ Archive::GetHashesStatus Archive::get_hashes(ZipSource *source, uint64_t length,
 
 
 void Archive::merge_files(const std::vector<File> &files_cache) {
+    set_cache_changed(NONE);
+
     for (uint64_t i = 0; i < files.size(); i++) {
         auto &file = files[i];
         
@@ -500,31 +506,37 @@ void Archive::merge_files(const std::vector<File> &files_cache) {
         auto it = std::find_if(files_cache.cbegin(), files_cache.cend(), [&file](const File &file_cache){ return file.name == file_cache.name; });
         if (it != files_cache.cend()) {
             if (file.mtime == (*it).mtime && file.compare_size_hashes(*it)) {
+                if ((file.hashes.get_types() & ~(it->hashes.get_types())) == 0) {
+                    changes[i].updated_hashes.clear();
+                }
+                else {
+                    changes[i].updated_hashes.insert(0);
+                }
                 file.hashes.merge((*it).hashes);
                 file.detector_hashes = it->detector_hashes;
             }
             else {
-                cache_changed = true;
+                set_cache_changed(FILES);
             }
         }
         else {
-            cache_changed = true;
+            set_cache_changed(FILES);
         }
         
         if (want_crc() && !file.hashes.has_type(Hashes::TYPE_CRC)) {
             if (!file_ensure_hashes(i, Hashes::TYPE_ALL)) {
                 file.broken = true;
                 if (it == files_cache.cend() || !(*it).broken) {
-                    cache_changed = true;
+                    set_cache_changed(FILES);
                 }
                 continue;
             }
-            cache_changed = true;
+            set_cache_changed(HASHES_ONLY);
         }
     }
     
     if (files.size() != files_cache.size()) {
-        cache_changed = true;
+        set_cache_changed(FILES);
     }
 }
 
@@ -619,7 +631,7 @@ bool Archive::compute_detector_hashes(const std::unordered_map<size_t, DetectorP
     }
     
     if (got_new_hashes) {
-        cache_changed = true;
+        set_cache_changed(HASHES_ONLY);
     }
     return got_new_hashes;
 }
@@ -649,7 +661,7 @@ bool Archive::compute_detector_hashes(size_t index, const std::unordered_map<siz
         return false;
     }
 
-    return Detector::compute_hashes(data, &file, detectors);
+    return Detector::compute_hashes(data, &file, db->detectors, &changes[index].updated_hashes);
 }
 
 
@@ -690,3 +702,10 @@ bool Archive::compare_size_hashes(size_t index, size_t detector_id, const FileDa
     
     return ok;
 }
+
+void Archive::set_cache_changed(Archive::CacheChange new_changed) {
+    if (new_changed == HASHES_ONLY && cache_changed == FILES) {
+        return;
+    }
+    cache_changed = new_changed;
+}
\ No newline at end of file
diff --git a/src/Archive.h b/src/Archive.h
index 6255b133..d228a38e 100644
--- a/src/Archive.h
+++ b/src/Archive.h
@@ -38,6 +38,7 @@
 #include <optional>
 #include <string>
 #include <unordered_map>
+#include <unordered_set>
 #include <utility>
 #include <vector>
 
@@ -125,6 +126,11 @@ struct hash<ArchiveContents::TypeAndName> {
 
 class Archive {
 public:
+    enum CacheChange {
+        NONE,
+        HASHES_ONLY,
+        FILES
+    };
     class Change {
     public:
         enum Status {
@@ -140,6 +146,7 @@ class Archive {
         std::string source_name;
         ZipSourcePtr source;
         std::string file;
+        std::unordered_set<size_t> updated_hashes;
     };
 
     static ArchivePtr open(const std::string &name, filetype_t filetype, where_t where, int flags);
@@ -190,6 +197,8 @@ class Archive {
     virtual std::string get_full_filename(uint64_t index) { return ""; }
     virtual std::string get_original_filename(uint64_t index) { return ""; }
 
+    void set_cache_changed(CacheChange new_changed);
+
     ArchiveContentsPtr contents;
     std::vector<File> &files;
     std::string &name;
@@ -197,7 +206,7 @@ class Archive {
     const where_t where;
     std::vector<Change> changes;
 
-    bool cache_changed;
+    CacheChange cache_changed{NONE};
     bool modified;
     
 protected:
diff --git a/src/ArchiveLibarchive.cc b/src/ArchiveLibarchive.cc
index bdd8b266..93b5c8a6 100644
--- a/src/ArchiveLibarchive.cc
+++ b/src/ArchiveLibarchive.cc
@@ -330,6 +330,7 @@ bool ArchiveLibarchive::read_infos_xxx() {
         r.name = archive_entry_pathname_utf8(entry);
         r.broken = false;
         files.push_back(r);
+        changes.emplace_back();
 
         header_read = true;
         file_ensure_hashes(current_index, Hashes::TYPE_ALL);
diff --git a/src/ArchiveZip.cc b/src/ArchiveZip.cc
index 19982485..38481157 100644
--- a/src/ArchiveZip.cc
+++ b/src/ArchiveZip.cc
@@ -248,7 +248,7 @@ void ArchiveZip::commit_cleanup() {
 
 
 void ArchiveZip::get_last_update() {
-    if (cache_changed) {
+    if (cache_changed != NONE) {
         close_xxx();
     }
     struct stat st;
diff --git a/src/CkmameDB.cc b/src/CkmameDB.cc
index f8fa58f4..f27056b0 100644
--- a/src/CkmameDB.cc
+++ b/src/CkmameDB.cc
@@ -114,7 +114,8 @@ std::unordered_map<CkmameDB::Statement, std::string> CkmameDB::queries = {
     { QUERY_ARCHIVE_ID, "select archive_id from archive where name = :name and file_type = :file_type" },
     { QUERY_ARCHIVE_LAST_CHANGE, "select mtime, size from archive where archive_id = :archive_id" },
     { QUERY_FILE, "select file_idx, detector_id, name, mtime, status, size, crc, md5, sha1 from file where archive_id = :archive_id order by file_idx, detector_id" },
-    { QUERY_HAS_ARCHIVES, "select archive_id from archive limit 1" }
+    { QUERY_HAS_ARCHIVES, "select archive_id from archive limit 1" },
+    { UPDATE_FILE_HASHES, "update file set crc = :crc, md5 = :md5, sha1 = :sha1 where archive_id = :archive_id and file_idx = :file_idx and detector_id = 0" }
 };
 
 std::unordered_map<CkmameDB::ParameterizedStatement, std::string> CkmameDB::parameterized_queries = {
@@ -515,4 +516,31 @@ bool CkmameDB::compute_detector_hashes(const std::unordered_map<size_t, Detector
     }
 
     return got_new_hashes;
-}
\ No newline at end of file
+}
+
+void CkmameDB::update_file_hashes(int archive_id, size_t file_id, const Hashes& hashes) {
+    auto stmt = get_statement(UPDATE_FILE_HASHES);
+
+    stmt->set_int("archive_id", archive_id);
+    stmt->set_int("file_idx", static_cast<int>(file_id));
+    stmt->set_hashes(hashes, true);
+
+    stmt->execute();
+}
+
+void CkmameDB::insert_file_detector_hashes(int archive_id, size_t file_id, size_t detector_id, const Hashes& hashes) {
+    auto local_detector_id = get_detector_id(detector_id);
+
+    auto stmt = get_statement(INSERT_FILE);
+
+    stmt->set_int("archive_id", archive_id);
+    stmt->set_int("file_idx", static_cast<int>(file_id));
+    stmt->set_uint64("detector_id", local_detector_id);
+    stmt->set_string("name", "", true);
+    stmt->set_int64("mtime", 0);
+    stmt->set_int("status", 0);
+    stmt->set_uint64("size", hashes.size);
+    stmt->set_hashes(hashes, true);
+
+    stmt->execute();
+}
diff --git a/src/CkmameDB.h b/src/CkmameDB.h
index 8e25119d..9fd32252 100644
--- a/src/CkmameDB.h
+++ b/src/CkmameDB.h
@@ -74,7 +74,8 @@ class CkmameDB : public DB {
         QUERY_ARCHIVE_ID,
         QUERY_ARCHIVE_LAST_CHANGE,
         QUERY_FILE,
-        QUERY_HAS_ARCHIVES
+        QUERY_HAS_ARCHIVES,
+        UPDATE_FILE_HASHES
     };
     enum ParameterizedStatement {
         QUERY_FIND_FILE
@@ -95,6 +96,8 @@ class CkmameDB : public DB {
     std::vector<ArchiveLocation> list_archives();
     int read_files(int archive_id, std::vector<File> *files);
     void write_archive(ArchiveContents *archive);
+    void update_file_hashes(int archive_id, size_t file_id, const Hashes& hashes);
+    void insert_file_detector_hashes(int archive_id, size_t file_id, size_t detector_id, const Hashes& hashes);
 
     void find_file(filetype_t filetype, size_t detector_id, const FileData& file, std::vector<FindResult> &results);
     bool compute_detector_hashes(const std::unordered_map<size_t, DetectorPtr>& detectors);
diff --git a/src/Detector.h b/src/Detector.h
index f450b4b2..410e9a97 100644
--- a/src/Detector.h
+++ b/src/Detector.h
@@ -35,6 +35,7 @@
 */
 
 #include <memory>
+#include <unordered_set>
 #include <vector>
 
 #include "DetectorCollection.h"
@@ -128,7 +129,7 @@ class Detector {
     static const DetectorDescriptor *get_descriptor(size_t id) { return detector_ids.get_descriptor(id); }
     
     // Returns true if new hashes were computed.
-    static bool compute_hashes(const std::vector<uint8_t> &data, File *file, const std::unordered_map<size_t, DetectorPtr> &detectors);
+    static bool compute_hashes(const std::vector<uint8_t> &data, File *file, const std::unordered_map<size_t, DetectorPtr> &detectors, std::unordered_set<size_t>* changed = {});
 
 private:
     static uint64_t operation_unit_size(Operation operation);
diff --git a/src/File.cc b/src/File.cc
index c0cf3aa4..5be5d6e8 100644
--- a/src/File.cc
+++ b/src/File.cc
@@ -37,7 +37,7 @@
 Hashes File::empty_hashes;
 
 bool File::has_all_hashes(size_t detector, int requested_types) const {
-    return hashes.has_all_types(requested_types) && get_hashes(detector).has_all_types(requested_types);
+    return get_hashes(detector).has_all_types(requested_types);
 }
 
 
diff --git a/src/archive_modify.cc b/src/archive_modify.cc
index 71d9c090..5bef8e3c 100644
--- a/src/archive_modify.cc
+++ b/src/archive_modify.cc
@@ -46,7 +46,7 @@ bool Archive::commit() {
     if (modified) {
         output.set_error_archive(name);
 
-        cache_changed = true;
+        set_cache_changed(FILES);
 
         if (!commit_xxx()) {
             return false;
@@ -86,7 +86,7 @@ bool Archive::commit() {
 }
 
 void Archive::update_cache() {
-    if (!cache_changed) {
+    if (cache_changed == NONE) {
         return;
     }
 
@@ -109,14 +109,38 @@ void Archive::update_cache() {
         }
         else {
             get_last_update();
-            
-            try {
-                contents->cache_db->write_archive(contents.get());
+
+            // TODO: check if size/mtime changed
+
+            if (contents->cache_id != 0 && cache_changed == HASHES_ONLY) {
+                for (size_t i = 0; i < changes.size(); i++) {
+                    auto& change = changes[i];
+                    const auto& file = files[i];
+
+                    if (change.updated_hashes.empty()) {
+                        continue;
+                    }
+
+                    for (auto detector_id: change.updated_hashes) {
+                        if (detector_id == 0) {
+                            contents->cache_db->update_file_hashes(contents->cache_id, i, file.hashes);
+                        }
+                        else {
+                            contents->cache_db->insert_file_detector_hashes(contents->cache_id, i, detector_id, file.get_hashes(detector_id));
+                        }
+                    }
+                    change.updated_hashes.clear();
+                }
             }
-            catch (Exception &exception) {
-                contents->cache_db->seterr();
-                output.error_database("%s: error writing to %s", name.c_str(), CkmameDB::db_name.c_str());
-                contents->cache_id = 0;
+            else {
+                try {
+                    contents->cache_db->write_archive(contents.get());
+                }
+                catch (Exception& exception) {
+                    contents->cache_db->seterr();
+                    output.error_database("%s: error writing to %s", name.c_str(), CkmameDB::db_name.c_str());
+                    contents->cache_id = 0;
+                }
             }
         }
     }
@@ -124,7 +148,7 @@ void Archive::update_cache() {
         contents->cache_id = 0;
     }
 
-    cache_changed = false;
+    set_cache_changed(NONE);
 }
 
 
@@ -260,7 +284,7 @@ bool Archive::file_rename(uint64_t index, const std::string &filename) {
 	return false;
     }
     if (changes[index].status != Change::EXISTS) {
-	output.archive_error("cannot copy broken/added/deleted file");
+	output.archive_error("cannot rename broken/added/deleted file");
 	return false;
     }
 
diff --git a/src/detector_execute.cc b/src/detector_execute.cc
index b7acda17..2e79936c 100644
--- a/src/detector_execute.cc
+++ b/src/detector_execute.cc
@@ -231,13 +231,22 @@ bool Detector::Test::execute(const std::vector<uint8_t> &data) const {
 }
 
 
-bool Detector::compute_hashes(const std::vector<uint8_t> &data, File *file, const std::unordered_map<size_t, DetectorPtr> &detectors) {
+bool Detector::compute_hashes(const std::vector<uint8_t> &data, File *file, const std::unordered_map<size_t, DetectorPtr> &detectors, std::unordered_set<size_t>* changed) {
     if (file->get_size(0) > MAX_DETECTOR_FILE_SIZE) {
         return false;
     }
     
-    for (const auto &pair : detectors) {
-        file->detector_hashes[pair.first] = pair.second->execute(data);
+    for (const auto &[id, detector] : detectors) {
+        auto it = file->detector_hashes.find(id);
+
+        if (it != file->detector_hashes.end() && !it->second.empty()) {
+            continue;
+        }
+
+        file->detector_hashes[id] = detector->execute(data);
+        if (changed) {
+            changed->insert(id);
+        }
     }
     
     return true;