fix(buffer): on session_end make sure we only add it to sessions if more events exists

packages/db/src/buffers/event-buffer-redis.ts

@@ -76,7 +76,7 @@ export class EventBuffer extends BaseBuffer {
 local sessionSortedKey = KEYS[1]
 local sessionPrefix = KEYS[2]
 local batchSize = tonumber(ARGV[1])
-local minEvents = tonumber(ARGV[2])  -- New parameter for minimum events
+local minEvents = tonumber(ARGV[2])
 
 local result = {}
 local sessionsToRemove = {}
@@ -200,6 +200,14 @@ return "OK"
       const multi = _multi || redis.multi();
 
       if (event.session_id && this.sessionEvents.includes(event.name)) {
+        const sessionKey = this.getSessionKey(event.session_id);
+        const addEventToSession = () => {
+          const score = new Date(event.created_at || Date.now()).getTime();
+          multi
+            .rpush(sessionKey, eventJson)
+            .zadd(this.sessionSortedKey, 'NX', score, event.session_id);
+        };
+
         if (event.name === 'screen_view') {
           multi.set(
             this.getLastEventKey({
@@ -210,21 +218,28 @@ return "OK"
             'EX',
             60 * 31,
           );
+
+          addEventToSession();
         } else if (event.name === 'session_end') {
+          // Delete last screen view
           multi.del(
             this.getLastEventKey({
               projectId: event.project_id,
               profileId: event.profile_id,
             }),
           );
+
+          // Check if session has any events
+          const eventCount = await redis.llen(sessionKey);
+
+          if (eventCount === 0) {
+            // If session is empty, add to regular queue and don't track in sorted set
+            multi.rpush(this.regularQueueKey, eventJson);
+          } else {
+            // Otherwise add to session as normal
+            addEventToSession();
+          }
         }
-
-        const sessionKey = this.getSessionKey(event.session_id);
-        const score = new Date(event.created_at || Date.now()).getTime();
-
-        multi
-          .rpush(sessionKey, eventJson)
-          .zadd(this.sessionSortedKey, 'NX', score, event.session_id);
       } else {
         // All other events go to regularQueue queue
         multi.rpush(this.regularQueueKey, eventJson);
@@ -339,7 +354,7 @@ return "OK"
       let now = performance.now();
       const [sessions, regularQueueEvents] = await Promise.all([
         // (A) Fetch session events
-        this.getEligableSessions({ minEventsInSession: 1 }),
+        this.getEligableSessions({ minEventsInSession: 2 }),
         // (B) Fetch no-session events
         redis.lrange(this.regularQueueKey, 0, this.batchSize / 2 - 1),
       ]);