Lags on an uploaded map

Hi,

This last Friday, I was looking for a server where I could play with my friend on, and I've seen this plateform. Since it has been free, I've just decided to try it and, once I started the server, Friday, everything was fine, I mean, no lags, no crash or anything bad, we could go on my friend and me and was playing.

But then, since yesterday, we've wanted to play an adventure map, then I had to download a map on my computer and upload it to the server, well, until this, nothing anormal.

But then, when I logged on my server, I was lagging a lot, just, unplayable but, my friend wasn't even lagging at all, that I actually don't understand.

Then, I've just been wondering, why I lag that much on the server, because when it's not an uploaded map, I don't lag, when it is, I lag a lot (and I even tried with other map, and one generated by myself, so, a really tiny map).

I've also tried to start the server from my friend, because I thought it could come from my connection that doesn't like when I start it, I don't know, but anyway, I was still lagging a lot.

I've tried many things to see if I can fix it, but nope, I can't, impossible to get ride of these awful lags.

Then, that is why I'm going to ask, if anyone could explain me why I am lagging that much (but not my friend), and even if someone knows how to fix this problem, I would appreciate a lot because it has been since really long that my friend and me wanted to play on a map, on our own server, only together, but then, here, I can't so and plus, I've tried a lot of random things, but still haven't got ride of it, so, I'm completely hopeless.

Anyway, thanks for your quick response, if anyone does.

Have a nice day, Polosage.

Thanks for replying quickly,

But actually, I haven't added any mods or plugins. I've also tried to play on other server (that I actually usually do) and the server where I've played is hosted in America, and I'm french, so I might just get more lags but actually, I don't even lag on this server.

When I tried to play on my server, I obviously checked my connection to see if everything was okay, and indeed, my connection was perfect, not any packet loss or anything. So I can tell you that it doesn't come from my connection since I've tested all this.

Also, I don't especially understand about "many world", you mean there can be more than one world one a single server then? If yes, to be honest, I've not known this and actuzlly don't know how to check all the worlds there are then.

And something else too, I don't understand what you mean by checking my logs. Where can I see this? Logs on server, or logs on my client, I don't know so, if it doesn't bother you to, if you could explain me this, thanks a lot.

Yes, I lag when the map on the server is an uploaded map and then, I don't really understand but, since it's an adventure map, there are command blocks. Though, I don't know and don't think all the amount of command blocks on this map is enough to make me lag and, why do I lag but not my friend? I just don't know.

Anyway, the map is in version 1.8, my server is in 1.8.9. But it's the same, my friend and me is using minecraft 1.8.9, then again, why me but not my friend?

I can send you a link or tell you the name of the map we would like to play on, so that you could check if you would want to, but it's not only on this map, I get a lot of lags on whatever map as long as the current map on the server has been uploaded, not generated directly from the server itself.

I also would like to know how the hosting works, I mean, is the server hosted by my connection when I launch it? Or then it's hosted elsewhere, but then, where, in what country?

Because maybe it can come from this then.

I don't have any mods on my client, only optifine.

But actually, I've found the source of these lags and to be honest, that is pretty weird:

For some unknown reasons, my client doesn't support a specific clock (the one that uses command blocks with /fill redstone block and /fill stone, the old one).

I don't understand how come I lag because of this clock whereas in solo, nothing bad happens, my client support it, but not when it's on a server so, I've just made the same clock but with more ticks so that it doesn't lag anymore.

But i don't really think that it comes from this, but maybe some commands that my client doesn't support with this speed, each tick.

But well, anyway, I think I've fixed the problem, so it's fine, normally even though I still get some lags but I think they come from my own connection or then because many people are using the Internet or I don't know what, but don't think it's going to keep lagging, at least, not as much as earlier.

Thanks for helping me though and if ever any constant lags happen again, I'll tell you, at least if I don't succeed in fixing them