diff --git a/analytics/analytics/analytic_unit_worker.py b/analytics/analytics/analytic_unit_worker.py
index 71844cc..7b00849 100644
--- a/analytics/analytics/analytic_unit_worker.py
+++ b/analytics/analytics/analytic_unit_worker.py
@@ -35,7 +35,8 @@ class AnalyticUnitWorker:
             raise Exception('Timeout ({}s) exceeded while learning'.format(config.LEARNING_TIMEOUT))
 
     async def do_detect(self, data: pd.DataFrame, cache: Optional[ModelCache]) -> dict:
-        return self._detector.detect(data, cache)
+        # TODO: return without await
+        return await self._detector.detect(data, cache)
 
     def cancel(self):
         if self._training_future is not None:
diff --git a/analytics/analytics/detectors/detector.py b/analytics/analytics/detectors/detector.py
index b0738a4..99de16b 100644
--- a/analytics/analytics/detectors/detector.py
+++ b/analytics/analytics/detectors/detector.py
@@ -14,7 +14,7 @@ class Detector(ABC):
         pass
 
     @abstractmethod
-    def detect(self, dataframe: DataFrame, cache: Optional[ModelCache]) -> dict:
+    async def detect(self, dataframe: DataFrame, cache: Optional[ModelCache]) -> dict:
         pass
 
     @abstractmethod
diff --git a/analytics/analytics/detectors/pattern_detector.py b/analytics/analytics/detectors/pattern_detector.py
index b84a348..b002dc7 100644
--- a/analytics/analytics/detectors/pattern_detector.py
+++ b/analytics/analytics/detectors/pattern_detector.py
@@ -1,10 +1,11 @@
 import models
 
+import asyncio
 import logging
 import config
 
 import pandas as pd
-from typing import Optional
+from typing import Optional, Generator
 
 from detectors import Detector
 from buckets import DataBucket
@@ -33,11 +34,12 @@ def resolve_model_by_pattern(pattern: str) -> models.Model:
 AnalyticUnitId = str
 class PatternDetector(Detector):
 
+    MIN_BUCKET_SIZE = 150
+
     def __init__(self, pattern_type: str, analytic_unit_id: AnalyticUnitId):
         self.analytic_unit_id = analytic_unit_id
         self.pattern_type = pattern_type
         self.model = resolve_model_by_pattern(self.pattern_type)
-        self.min_bucket_size = 150
         self.bucket = DataBucket()
 
     def train(self, dataframe: pd.DataFrame, segments: list, cache: Optional[models.ModelCache]) -> models.ModelCache:
@@ -49,12 +51,32 @@ class PatternDetector(Detector):
             'cache': new_cache
         }
 
-    def detect(self, dataframe: pd.DataFrame, cache: Optional[models.ModelCache]) -> dict:
+    async def detect(self, dataframe: pd.DataFrame, cache: Optional[models.ModelCache]) -> dict:
         logger.debug('Unit {} got {} data points for detection'.format(self.analytic_unit_id, len(dataframe)))
         # TODO: split and sleep (https://github.com/hastic/hastic-server/pull/124#discussion_r214085643)
-        detected = self.model.detect(dataframe, self.analytic_unit_id, cache)
 
-        segments = [{ 'from': segment[0], 'to': segment[1] } for segment in detected['segments']]
+        if not cache:
+            msg = f'{self.analytic_unit_id} detection got invalid cache {cache}, skip detection'
+            logger.error(msg)
+            raise ValueError(msg)
+
+        window_size = cache.get('WINDOW_SIZE')
+
+        if not window_size:
+            msg = f'{self.analytic_unit_id} detection got invalid window size {window_size}'
+
+        chunks = self.__get_data_chunks(dataframe, window_size)
+
+        segments = []
+        segment_parser = lambda segment: { 'from': segment[0], 'to': segment[1] }
+        for chunk in chunks:
+            await asyncio.sleep(0)
+            detected = self.model.detect(dataframe, self.analytic_unit_id, cache)
+            for detected_segment in detected['segments']:
+                detected_segment = segment_parser(detected_segment)
+                if detected_segment not in segments:
+                    segments.append(detected_segment)
+
         newCache = detected['cache']
 
         last_dataframe_time = dataframe.iloc[-1]['timestamp']
@@ -76,7 +98,7 @@ class PatternDetector(Detector):
         if cache == None:
             logging.debug('Recieve_data cache is None for task {}'.format(self.analytic_unit_id))
             cache = {}
-        bucket_size = max(cache.get('WINDOW_SIZE', 0) * 3, self.min_bucket_size)
+        bucket_size = max(cache.get('WINDOW_SIZE', 0) * 3, self.MIN_BUCKET_SIZE)
 
         res = self.detect(self.bucket.data, cache)
 
@@ -88,3 +110,31 @@ class PatternDetector(Detector):
             return res
         else:
             return None
+
+    def __get_data_chunks(self, dataframe: pd.DataFrame, window_size: int) -> Generator[pd.DataFrame, None, None]:
+        """
+        TODO: fix description
+        Return generator, that yields dataframe's chunks. Chunks have 3 WINDOW_SIZE length and 2 WINDOW_SIZE step.
+        Example: recieved dataframe: [0, 1, 2, 3, 4, 5], returned chunks [0, 1, 2], [2, 3, 4], [4, 5].
+        """
+        chunk_size = window_size * 100
+        intersection = window_size
+
+        data_len = len(dataframe)
+
+        if data_len < chunk_size:
+            return (chunk for chunk in (dataframe,))
+
+        def slices():
+            nonintersected = chunk_size - intersection
+            mod = data_len % nonintersected
+            chunks_number = data_len // nonintersected
+
+            offset = 0
+            for i in range(chunks_number):
+                yield slice(offset, offset + nonintersected + 1)
+                offset += nonintersected
+
+            yield slice(offset, offset + mod)
+
+        return (dataframe[chunk_slice] for chunk_slice in slices())
diff --git a/analytics/analytics/detectors/threshold_detector.py b/analytics/analytics/detectors/threshold_detector.py
index dc5320f..2790a1f 100644
--- a/analytics/analytics/detectors/threshold_detector.py
+++ b/analytics/analytics/detectors/threshold_detector.py
@@ -25,7 +25,7 @@ class ThresholdDetector(Detector):
             }
         }
 
-    def detect(self, dataframe: pd.DataFrame, cache: ModelCache) -> dict:
+    async def detect(self, dataframe: pd.DataFrame, cache: ModelCache) -> dict:
         if cache == None:
             raise 'Threshold detector error: cannot detect before learning'
         value = cache['value']
diff --git a/analytics/bin/server b/analytics/bin/server
index d84647f..996c9ec 100755
--- a/analytics/bin/server
+++ b/analytics/bin/server
@@ -100,7 +100,7 @@ async def app_loop():
 
 if __name__ == "__main__":
     loop = asyncio.get_event_loop()
-    loop.set_debug(True)
+    #loop.set_debug(True)
     logger.info("Ok")
     server_service, data_service, analytic_unit_manager = init_services()
     print('Analytics process is running') # we need to print to stdout and flush
diff --git a/analytics/tests/test_detector_chunks.py b/analytics/tests/test_detector_chunks.py
new file mode 100644
index 0000000..3bef5d5
--- /dev/null
+++ b/analytics/tests/test_detector_chunks.py
@@ -0,0 +1,22 @@
+import unittest
+from detectors.pattern_detector import PatternDetector
+
+def rlist(start, stop):
+        return [x for x in range(start, stop + 1)]
+class TestUtils(unittest.TestCase):
+
+    def test_chunks_generator(self):
+        window_size = 1
+
+        cases = [
+            ([], [[]]),
+            (rlist(0, 300), [rlist(0,99),rlist(99,198),rlist(198,297),rlist(297,300)])
+        ]
+
+        for data, expected_chunks in cases:
+            chunks = tuple(PatternDetector._PatternDetector__get_data_chunks(None, data, window_size))
+            self.assertSequenceEqual(chunks, expected_chunks)
+
+
+if __name__ == '__main__':
+    unittest.main()