Deflakes Primary COB growth with inactive replica (#2715)

Resolves #2696 

The primary issue was that with sanitizer mode, the test needed more
time for primary’s replication buffers grow beyond `2 × backlog_size`.
Increasing the threshold of `repl-timeout` to 30s, ensures that the
inactive replica is not disconnected while the full sync is proceeding.
`rdb-key-save-delay` controls or throttles the data written to the
client output buffer, and in this case, we are deterministically able to
perform the fullsync within 10s (10000 keys * 0.001s).

Increasing the `wait_for_condition` gives it enough retries to verify
that `mem_total_replication_buffers` reaches the required `2 ×
backlog_size`.

Signed-off-by: Sarthak Aggarwal <[email protected]>

Author: sarthakaggarwal97

tests/integration/dual-channel-replication.tcl

@@ -537,10 +537,12 @@ start_server {tags {"dual-channel-replication external:skip"}} {
             $primary config set repl-timeout 100
             $replica config set repl-timeout 100
         } else {
-            $primary config set repl-timeout 10            
-            $replica config set repl-timeout 10
+            $primary config set repl-timeout 30
+            $replica config set repl-timeout 30
         }
-        $primary config set rdb-key-save-delay 200
+
+        # Avoids timeout by keeping the RDB child alive longer while the replica is inactive
+        $primary config set rdb-key-save-delay 1000
         populate 10000 primary 10000
 
         set load_handle1 [start_one_key_write_load $primary_host $primary_port 100 "mykey1"]
@@ -556,10 +558,11 @@ start_server {tags {"dual-channel-replication external:skip"}} {
         test "dual-channel-replication: Primary COB growth with inactive replica" {
             $replica replicaof $primary_host $primary_port
             # Verify repl backlog can grow
-            wait_for_condition 1000 10 {
+            wait_for_condition 2000 10 {
                 [s 0 mem_total_replication_buffers] > [expr {2 * $backlog_size}]
             } else {
-                fail "Primary should allow backlog to grow beyond its limits during dual-channel-replication sync handshake"
+                set cur [s 0 mem_total_replication_buffers]
+                fail "Primary should allow backlog (have=$cur, need>[expr {2 * $backlog_size}]) to grow beyond its limits during dual-channel-replication sync handshake"
             }
             wait_and_resume_process -1