NodeMCU exception error with firebase.getstring()

I am uaing NodeMCU for getting values from firebase. I have used the fibrebase.getstring() in the loop function and checked the value for triggering the pin. It works great but after some couple of minutes (generally takes 1 minute), NodeMCU restarts printing excetion (28) <<<<stack and values. How can i solve this problem? Can someone help?

Getting this error for each stored value up to 49.0
The process continues after restart and error occur at exact value 49.0
Error shown below:

connecting.......
19:17:03.765 -> connected: 192.168.1.103
19:17:08.425 -> Stored
19:17:08.425 -> number: 0.00
19:17:09.265 -> Stored
19:17:09.265 -> number: 1.00
19:17:10.080 -> Stored
19:17:10.080 -> number: 2.00
19:17:11.041 -> Stored
19:17:11.041 -> number: 3.00
19:17:11.906 -> Stored
19:17:11.906 -> number: 4.00
19:17:12.906 -> Stored
19:17:12.906 -> number: 5.00
19:17:13.887 -> Stored
19:17:13.887 -> number: 6.00
19:17:14.967 -> Stored
19:17:14.967 -> number: 7.00
19:17:16.737 -> Stored
19:17:16.737 -> number: 8.00
19:17:18.381 -> Stored
19:17:18.381 -> number: 9.00
19:17:19.683 -> Stored
19:17:19.683 -> number: 10.00
19:17:21.028 -> Stored
19:17:21.028 -> number: 11.00
19:17:22.472 -> Stored
19:17:22.472 -> number: 12.00
19:17:23.615 -> Stored
19:17:23.615 -> number: 13.00
19:17:24.678 -> Stored
19:17:24.678 -> number: 14.00
19:17:25.987 -> Stored
19:17:25.987 -> number: 15.00
19:17:26.966 -> Stored
19:17:26.966 -> number: 16.00
19:17:27.825 -> Stored
19:17:27.825 -> number: 17.00
19:17:28.867 -> Stored
19:17:28.867 -> number: 18.00
19:17:30.494 -> Stored
19:17:30.494 -> number: 19.00
19:17:31.354 -> Stored
19:17:31.354 -> number: 20.00
19:17:32.688 -> Stored
19:17:32.688 -> number: 21.00
19:17:34.286 -> Stored
19:17:34.286 -> number: 22.00
19:17:35.563 -> Stored
19:17:35.563 -> number: 23.00
19:17:37.443 -> Stored
19:17:37.443 -> number: 24.00
19:17:38.537 -> Stored
19:17:38.537 -> number: 25.00
19:17:40.043 -> Stored
19:17:40.043 -> number: 26.00
19:17:41.826 -> Stored
19:17:41.826 -> number: 27.00
19:17:42.953 -> Stored
19:17:42.953 -> number: 28.00
19:17:46.185 -> Stored
19:17:46.185 -> number: 29.00
19:17:49.601 -> Stored
19:17:49.601 -> number: 30.00
19:17:50.889 -> Stored
19:17:50.889 -> number: 31.00
19:17:51.917 -> Stored
19:17:51.917 -> number: 32.00
19:17:52.894 -> Stored
19:17:52.894 -> number: 33.00
19:17:54.303 -> Stored
19:17:54.303 -> number: 34.00
19:17:55.670 -> Stored
19:17:55.670 -> number: 35.00
19:17:56.655 -> Stored
19:17:56.655 -> number: 36.00
19:17:57.915 -> Stored
19:17:57.915 -> number: 37.00
19:17:59.121 -> Stored
19:17:59.121 -> number: 38.00
19:18:00.221 -> Stored
19:18:00.221 -> number: 39.00
19:18:01.361 -> Stored
19:18:01.361 -> number: 40.00
19:18:02.626 -> Stored
19:18:02.626 -> number: 41.00
19:18:04.233 -> Stored
19:18:04.233 -> number: 42.00
19:18:05.586 -> Stored
19:18:05.586 -> number: 43.00
19:18:06.714 -> Stored
19:18:06.714 -> number: 44.00
19:18:07.865 -> Stored
19:18:07.865 -> number: 45.00
19:18:09.300 -> Stored
19:18:09.300 -> number: 46.00
19:18:10.261 -> Stored
19:18:10.261 -> number: 47.00
19:18:11.304 -> Stored
19:18:11.304 -> number: 48.00
19:18:12.666 -> Stored
19:18:12.666 -> number: 49.00
19:18:13.430 -> 
19:18:13.430 -> Exception (9):
19:18:13.430 -> epc1=0x4020b5b8 epc2=0x00000000 epc3=0x00000000 excvaddr=0x6f6879a1 depc=0x00000000
19:18:13.430 -> 
19:18:13.430 -> >>>stack>>>
19:18:13.430 -> 
19:18:13.430 -> ctx: cont
19:18:13.430 -> sp: 3ffffc80 end: 3fffffc0 offset: 01a0
19:18:13.430 -> 3ffffe20:  0000000b 3ffee918 3ffef9d8 40205aa8  
19:18:13.468 -> 3ffffe30:  3ffe8760 000001bb 3ffef9d8 40206980  
19:18:13.468 -> 3ffffe40:  3ffe8814 0000003b 3ffef9d8 40206dc8  
19:18:13.468 -> 3ffffe50:  0000003b 3ffee918 0000002e 402034c0  
19:18:13.468 -> 3ffffe60:  3ffffea8 0000003b 3ffffe90 40207a50  
19:18:13.468 -> 3ffffe70:  3ffee914 3ffffe90 3ffe8814 3fffff10  
19:18:13.468 -> 3ffffe80:  3ffee914 3ffffed4 3ffef9d4 40204dab  
19:18:13.468 -> 3ffffe90:  3ffefb1c 003b003f 00fffed4 3ffefcf4  
19:18:13.468 -> 3ffffea0:  003a003f 00fefaec 3ffefc7c 001b001f  
19:18:13.468 -> 3ffffeb0:  00000b28 3ffee970 3ffefaee 3fffff10  
19:18:13.532 -> 3ffffec0:  3ffee914 3ffe8810 3ffef754 40202b10  
19:18:13.532 -> 3ffffed0:  3ffee910 3ffefa78 00000020 3ffef754  
19:18:13.532 -> 3ffffee0:  3ffefaec 3fffff10 3ffefaec 40203484  
19:18:13.532 -> 3ffffef0:  3fffff20 00000000 00000003 3ffef754  
19:18:13.532 -> 3fffff00:  3ffefaec 3fffff18 3ffee910 40204bfc  
19:18:13.532 -> 3fffff10:  3ffefc70 00000002 3ffef7a0 3ffefaee  
19:18:13.532 -> 3fffff20:  3ffee970 3fe00000 00000900 3ffe889b  
19:18:13.532 -> 3fffff30:  00000002 3fffff60 3fffff80 40206e50  
19:18:13.532 -> 3fffff40:  00000006 00000000 00000001 3ffe889b  
19:18:13.532 -> 3fffff50:  3ffee910 3ffee8cc 3ffee9ac 40204c40  
19:18:13.532 -> 3fffff60:  00000008 42480000 3ffe889b 40207a86  
19:18:13.532 -> 3fffff70:  00000000 00000000 3ffee9ac 40201126  
19:18:13.532 -> 3fffff80:  626d756e 00007265 86000001 40100154  
19:18:13.532 -> 3fffff90:  3fffdad0 00000000 3ffee9ac 3ffee9ec  
19:18:13.548 -> 3fffffa0:  3fffdad0 00000000 3ffee9ac 402088f4  
19:18:13.548 -> 3fffffb0:  feefeffe feefeffe 3ffe8580 40100be1  
19:18:13.548 -> <<<stack<<<
19:18:13.585 -> 
19:18:13.585 ->  ets Jan  8 2013,rst cause:2, boot mode:(3,6)
19:18:13.585 -> 
19:18:13.585 -> load 0x4010f000, len 1392, room 16 
19:18:13.585 -> tail 0
19:18:13.585 -> chksum 0xd0
19:18:13.585 -> csum 0xd0
19:18:13.585 -> v3d128e5c
19:18:13.585 -> ~ld

The code I used:

#include <ESP8266WiFi.h>
#include <FirebaseArduino.h>

// Set these to run example.
#define FIREBASE_HOST "Url"
#define FIREBASE_AUTH "Auth"
#define WIFI_SSID "SSID"
#define WIFI_PASSWORD "Password"

void setup() {
 Serial.begin(115200);

 // connect to wifi.
 WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
 Serial.print("connecting");
 while (WiFi.status() != WL_CONNECTED) {
   Serial.print(".");
   delay(500);
 }
 Serial.println();
 Serial.print("connected: ");
 Serial.println(WiFi.localIP());
 
 Firebase.begin(FIREBASE_HOST, FIREBASE_AUTH);
}
float a=0.0;
void loop() {
 // set value
 
 Firebase.setFloat("number",a);
 Serial.println("Stored");
 yield();
 
 if (Firebase.failed()) {
     Serial.print("setting /number failed:");
     Serial.println(Firebase.error());  
     return;
 }

 
 Serial.print("number: ");
 Serial.println(Firebase.getFloat("number"));
 yield();

 a=a+1.0;

 
}

When you post code please use code tags as described in Read this before posting a programming question.

Then look down to item #7 about how to post your code.
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I am not the least familiar with Firebase. But, Exception 9 is basically a stack crash. I've never used it but here is an Exception Decoder you might try.

You aren't getting a WDT crash, so all the yield() statements are superfluous.

I don't see anything in the code that would cause a stack or heap overflow, but, again, I don't know what's happening in Firebase.

Does it always crash on the 50th Firebase.set()?

Yes, it always crashes in 50th firebase.get

So what is the below doing? Are you creating something that goes out of bounds on the 50th iteration?

a=a+1.0;

Rachhakshahu:
Yes, it always crashes in 50th firebase.get

As I said, I see nothing in your code that would crash the Arduino, so the problem has to be in Firebase. I would research your Firebase host to determine if there is a limit to your data storage.

zoomkat:
So what is the below doing? Are you creating something that goes out of bounds on the 50th iteration?

a=a+1.0;

I was just experimenting. Storing the updated value and retriving it from the database to see how it worked. But I got error on 50th time.