Set maximum memory to be used for indexes, when the limit is reached …

…the oldest used index is dropped

src/main.py

@@ -9,11 +9,16 @@
 import hashlib
 import asyncio
 import time
+import gc
 class Runner (JobRunner):
     INDEXES={}
     SEARCH_QUEUE = []
+    MAX_MEMORY_CACHE_GB = 1
+
     def __init__(self, filters, meta, template, sockets):
         super().__init__(filters, meta, template, sockets)
+        self.MAX_MEMORY_CACHE_GB = int(os.getenv('MAX_MEMORY_CACHE_GB', self.MAX_MEMORY_CACHE_GB))
+
 
     async def deserializeFromBlob(self,  url,  out_vectors , out_content):
         blobStorage = await self.openStorage( url)
@@ -162,10 +167,20 @@ def getParamValue(key,default=None):
             self.log("Creating faiss index")
             faiss_index = faiss.IndexFlatL2(shape[0])
             faiss_index.add(index_vectors)
-            index = [faiss_index, time.time(), index_content]
+            indexSizeGB = faiss_index.ntotal * shape[0] * 4 / 1024 / 1024 / 1024
+            index = [faiss_index, time.time(), index_content, indexSizeGB]
             self.INDEXES[indexId] = index
+
+            # drop oldest index if out of memory limit
+            totalSize = sum([x[3] for x in self.INDEXES.values()])
+            while totalSize > self.MAX_MEMORY_CACHE_GB:
+                oldest = min(self.INDEXES.values(), key=lambda x: x[1])
+                self.log("Max cache size reached. Dropping oldest index.")
+                del self.INDEXES[oldest]
+                totalSize -= oldest[3]
+            gc.collect()
+
 
-            # TODO: drop oldest index if out of memory limit
 
         else:
             self.log("Index already loaded")