feat(relay): add maxTotalEventsPerReq to cap aggregate events across filters

src/DBQuery.h

@@ -290,6 +290,7 @@ struct DBQuery : NonCopyable {
     flat_hash_set<uint64_t> sentEventsCurr;
     uint64_t lastWorkChecked = 0;
 
+    uint64_t maxTotalEvents = 0;
     uint64_t currScanTime = 0;
     uint64_t currScanSaveRestores = 0;
     uint64_t totalTime = 0;
@@ -319,6 +320,7 @@ struct DBQuery : NonCopyable {
                 }
 
                 sentEventsCurr.insert(levId);
+                if (maxTotalEvents > 0 && sentEventsFull.size() >= maxTotalEvents) return true;
                 return sentEventsCurr.size() >= f.limit;
             }, [&](uint64_t approxWork){
                 if (approxWork > lastWorkChecked + 2'000) {
@@ -355,6 +357,11 @@ struct DBQuery : NonCopyable {
 
             currScanTime = 0;
             currScanSaveRestores = 0;
+
+            if (maxTotalEvents > 0 && sentEventsFull.size() >= maxTotalEvents) {
+                LW << "[" << sub.connId << "] REQ='" << sub.subId.sv() << "' hit maxTotalEventsPerReq limit (" << maxTotalEvents << ")";
+                break;
+            }
         }
 
         if (logMetrics) {

src/QueryScheduler.h

@@ -33,6 +33,7 @@ struct QueryScheduler : NonCopyable {
         }
 
         DBQuery *q = new DBQuery(sub);
+        q->maxTotalEvents = cfg().relay__maxTotalEventsPerReq;
 
         connQueries.try_emplace(q->sub.subId, q);
         running.push_front(q);

src/apps/relay/golpe.yaml

@@ -73,6 +73,9 @@ config:
   - name: relay__maxFilterLimit
     desc: "Maximum records that can be returned per filter"
     default: 500
+  - name: relay__maxTotalEventsPerReq
+    desc: "Maximum total events returned across all filters in a REQ (0 = unlimited)"
+    default: 0
   - name: relay__maxTagsPerFilter
     desc: "Maximum number of tag filters allowed per filter (O(N^2) in matching, so keep it small)"
     default: 3

strfry.conf

@@ -110,6 +110,9 @@ relay {
     # Maximum records that can be returned per filter
     maxFilterLimit = 500
 
+    # Maximum total events returned across all filters in a REQ (0 = unlimited)
+    maxTotalEventsPerReq = 0
+
     # Maximum number of tag filters allowed per filter
     maxTagsPerFilter = 3