Object statistics lru

core/events.go

@@ -1,18 +1,6 @@
 package core
 
-import "log"
-
-// InitStore replays the AOF file on startup to restore persisted data
-// Call this once before accepting any client connections
-func InitStore() {
-	log.Println("Initializing store — replaying AOF if available...")
-	ReplayAOF()
-	log.Println("Store initialized, total keys:", StoreLen())
-}
-
 func Shutdown(){
 	//this function internally invokes BGREWRITEAOF, it would take the in-memory hash table and dump in it AOF File(Append only file)
-	log.Println("Shutting down — dumping AOF...")
 	evalBGREWRITEAOF([]string{})
-	log.Println("Shutdown complete")
 }

main.go

@@ -2,6 +2,14 @@
 package main 
 
 import(
+"flag"
+"log"
+"os"
+"os/signal"
+"syscall"
+"sync"  
+"github.com/sharpsalt/Velox-In-Memory-Database/server"
+"github.com/sharpsalt/Velox-In-Memory-Database/config"
 	"flag"
 	"log"
 	"os"
@@ -40,6 +48,7 @@ func main(){
 	/*
 	I will be running Synchronous TCP Server means i iwll be starting the TCP connection on give port synchronously
 	*/
+	var sigs cha os.Signal=make(chan os.Signal,1)
 	var sigs chan os.Signal=make(chan os.Signal,1)
 	/*
 	we will listen to interrupts or signals is through a channel

server/async_tcp.go

@@ -18,6 +18,33 @@
 var cronFrequency time.Duration=1*time.Second //a cron frequency of 1s
 var lastCronExecTime time.Time=time.Now() //and we are maintaining, last time it ran
 const EngineStatus_BUSY int32=1<<2
+const EngineStatus_WAITING=1<<1
+const EngineStatus_SHUTTING_DOWN int32=1<<3
+
+
+var eStatus int32=EngineStatus_WAITING
+
+func WaitForSignal(wg *sync.WaitGroup,sigs chan os.Signal){
+	defer wg.Done()
+	<-sigs  //this is a blcoking call like until we give a channel
+	//we would not be moving forward
+
+	//if servers is busy cntinue to work
+	for atomic.LoadInt32(&eStatus)==EngineStatus_BUSY{
+	}
+
+	//CRITICAL to hanle
+	//we do not want server to ever go back to BUSY State 
+	//when control flow is here
+
+	//immediately set the status to be SHUTTING _DOWN
+	//the only place where we can set the status to be SHUTTING_DONW
+	atomic.StoreInt32(&eStatus,EngineStatus_SHUTTING_DOWN)
+
+	//if server is in any other statem initiate a shutdown
+	core.ShutDown()
+	os.Exit(0)
+}
 const EngineStatus_WAITING int32=1<<1
 const EngineStatus_SHUTTING_DOWN int32=1<<3
 const EngineStatus_TRANSACTION int32=1<<4
@@ -212,6 +239,8 @@
 		//that why i am invoking EPOLL wait
 
 		//see if any FD is ready for an IO
+		nevents, e := syscall.EpollWait(epollFD, events[:], -1) //EpollWait mtlb some file descriptor is ready for IO 
+		//EpollWait will monitor if any IO is ready, and put it in buffer(evenets buffer), if none is there then the call wouldget blocked
 		// #10 FIX: 100ms timeout instead of -1 (blocking forever)
 		// With -1, the cron job (DeleteExpiredKey) would NEVER run because
 		// EpollWait blocks until an IO event arrives. With 100ms timeout,
@@ -283,9 +312,12 @@
 		//mark engine as WAITING
 		//no contention as the signal handler is blocked until
 		//the engine is BUSY
+		atomic.StoreInt32(&eStatus<EngineStatus_WAITING)
+	}
+	return nil
 		atomic.StoreInt32(&eStatus, EngineStatus_WAITING)
 	}
 	return nil
 }
 
 // respondAsync calls EvalAndRespond for the async server path