Will the EA crash ?
I've got an ea that downloaded all available ticks from a broker for a symbol .
It reached 250 million ticks , and , the MqlTick structure is 52 bytes per tick. (13 gigabytes)
It placed it all in memory .I've got decent RAM on the machine so it held.
If someone with 8GB of RAM runs it will they get OutOfMemory , Array out of range or will the swap file be used ? (if its called the swap file , the virtual memory)
Why are you thinking it placed all in memory ?
Slowing down ? It's hard to know what you are talking about exactly.
You can check the memory used by MT5 with Windows Task Manager.
If you used CopyTicks or CopyTicksRange, the data will be cached (so in memory), but I guess that if the computer memory is not sufficient only a part will be cached (this would need to be checked). The cache is then cleared after 30 minutes.
If you downloaded from the Symbols window, then it's not in memory at all.
Slowing down ? It's hard to know what you are talking about exactly.
You can check the memory used by MT5 with Windows Task Manager.
If you used CopyTicks or CopyTicksRange, the data will be cached (so in memory), but I guess that if the computer memory is not sufficient only a part will be cached (this would need to be checked). The cache is then cleared after 30 minutes.
If you downloaded from the Symbols window, then it's not in memory at all.
these files are the cache ?
That's the ticks data files, yes.
So when you use CopyTicks() and there is no data they will be download. If the data files are present they will be loaded in memory. That's what I am calling the cached data. They will remain in memory for 30 minutes (unless you used them of course).
I just tried to download a lot of ticks at once with CopyTIcksRange() and I got an error 4004 (as documented).
| ERR_NOT_ENOUGH_MEMORY | 4004 | Not enough memory to perform the system function |
That's the ticks data files, yes.
So when you use CopyTicks() and there is no data they will be download. If the data files are present they will be loaded in memory. That's what I am calling the cached data. They will remain in memory for 30 minutes (unless you used them of course).
I just tried to download a lot of ticks at once with CopyTIcksRange() and I got an error 4004 (as documented).
| ERR_NOT_ENOUGH_MEMORY | 4004 | Not enough memory to perform the system function |
Yeah , i noticed it keeps stacking them up in the array until it hits the memory limit , so i assume there will be gaps in the array , logically , since it does not crash.
#property version "1.00" int OnInit() { //--- EventSetMillisecondTimer(44); //--- return(INIT_SUCCEEDED); } void OnTimer(){ EventKillTimer(); int attempts=0; int ping=-1; datetime cursor=flatten(TimeTradeServer()); long cursorMSC=((long)cursor)*1000; long jump=2592000000;//60*60*24*30*1000; MqlTick receiver[]; long oldest=LONG_MAX; Comment("PleaseWait"); while(attempts<5){ ping=CopyTicks(_Symbol,receiver,COPY_TICKS_ALL,cursorMSC,1); if(ping==1){ if(receiver[0].time_msc==oldest){attempts++;}else{attempts=0;} if(receiver[0].time_msc<oldest){oldest=receiver[0].time_msc;} cursorMSC-=jump; } else{ attempts++; } Sleep(44); Comment("Oldest Tick : "+TimeToString((datetime)(oldest/1000),TIME_DATE|TIME_MINUTES|TIME_SECONDS)+"\nCursor("+TimeToString((datetime)(cursorMSC/1000),TIME_DATE|TIME_MINUTES|TIME_SECONDS)+")\nAttempts("+IntegerToString(attempts)+")\nPlease wait for response..."); } //we have the oldest tick here //request all ticks from the oldest if(oldest!=LONG_MAX){ Print("Requesting all ticks since "+TimeToString((datetime)(oldest/1000),TIME_DATE|TIME_MINUTES|TIME_SECONDS)); int all_ticks=CopyTicks(_Symbol,receiver,COPY_TICKS_ALL,oldest,-1);//1000000);//-1); Print("All ticks downloaded "+IntegerToString(all_ticks)); Print("Oldest "+TimeToString(receiver[0].time,TIME_DATE|TIME_MINUTES|TIME_SECONDS)); Print("Newest "+TimeToString(receiver[all_ticks-1].time,TIME_DATE|TIME_MINUTES|TIME_SECONDS)); }else{ Print("Cannot find oldest tick"); } Print("DONE"); ExpertRemove(); } datetime flatten(datetime _time){ MqlDateTime mqt; if(TimeToStruct(_time,mqt)){ mqt.day=1; mqt.hour=0; mqt.min=0; mqt.sec=0; _time=StructToTime(mqt); } return(_time); } void OnDeinit(const int reason){} void OnTick(){} //BASIC TICKS PACKER
Yeah , i noticed it keeps stacking them up in the array until it hits the memory limit , so i assume there will be gaps in the array , logically , since it does not crash.
Gaps ? It should not have gaps. Unless you make it on purpose.
By the way, just for information the MqlTick structure size is 60, not 52.
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I've got an ea that downloaded all available ticks from a broker for a symbol .
It reached 250 million ticks , and , the MqlTick structure is 52 bytes per tick. (13 gigabytes)
It placed it all in memory .I've got decent RAM on the machine so it held.
If someone with 8GB of RAM runs it will they get OutOfMemory , Array out of range or will the swap file be used ? (if its called the swap file , the virtual memory)