implement area size heuristic for area:id queries

[tyrasd]

fixes #359. The implementation feels a bit hacky / inefficient (since we need to iterate twice over all areas now), but I didn't see another way to access the area's used_indices property. Any pointers for possible improvements are welcome.

[mmd-osm]

int counter = 0 in line 311 should probably be removed as well, otherwise line 321 won't return the correct value I guess (variable counter gets shadowed).

[tyrasd]

right! forgot to remove that one

[mmd-osm]

Can you check if you could use it.handle() ... instead to get the id (avoids some unneeded object instatiation) - not super urgent.

[tyrasd]

you mean just changing it to it.handle().object().id.val(), right? For me that seems to works as well.

It probably should also be changed on line 244…

[mmd-osm]

I had it.handle().id() in mind - we have something similar elsewhere but I don't know if this also works in this context without further checking.

[tyrasd]

ah, yes, that makes more sense 🙈 -> 4d9992d

[mmd-osm]

I think even the .val() at the end is not needed as id() already returns the right type. Can you maybe test this again?

[tyrasd]

Then I get the following compile-time error (gcc 6.2):

error: no match for ‘operator==’ (operand types are ‘long long int’ and ‘Area_Skeleton::Id_Type {aka Uint32_Index}’

Uint32_Index has the == operator implemented only for comparing with other Uint32_Index values while Area_Query_Statement (for some reason) stores the id it gets in a 64bit integer.

But I think that calling .val() here shouldn't be an issue, since the compiler can inline/optimize that away very easily.

[mmd-osm]

Ok, fine, let's keep val(). I didn't have the source available when commenting and didn't exactly remember when it was necessary.

[mmd-osm]

Cherry-picked the changes to my branch, tested both variants. Memory consumption looks good, there's a somewhat larger runtime in one case, which is due to some unrelated code in area_query.cc. Bottom line: result is still way better than before, though.

way["building"](area:3600285864);out;

Command being timed: "./osm3s_query"
User time (seconds): 5.54
System time (seconds): 0.10
Percent of CPU this job got: 99%
Elapsed (wall clock) time (h:mm:ss or m:ss): 0:05.65
Average shared text size (kbytes): 0
Average unshared data size (kbytes): 0
Average stack size (kbytes): 0
Average total size (kbytes): 0
Maximum resident set size (kbytes): 123124
Average resident set size (kbytes): 0
Major (requiring I/O) page faults: 0
Minor (reclaiming a frame) page faults: 31456
Voluntary context switches: 13
Involuntary context switches: 487
Swaps: 0
File system inputs: 0
File system outputs: 0
Socket messages sent: 0
Socket messages received: 0
Signals delivered: 0
Page size (bytes): 4096
Exit status: 0

---

area(3600285864);
way["building"](area._);
out;

Command being timed: "./osm3s_query"
User time (seconds): 3.58
System time (seconds): 0.09
Percent of CPU this job got: 99%
Elapsed (wall clock) time (h:mm:ss or m:ss): 0:03.67
Average shared text size (kbytes): 0
Average unshared data size (kbytes): 0
Average stack size (kbytes): 0
Average total size (kbytes): 0
Maximum resident set size (kbytes): 122904
Average resident set size (kbytes): 0
Major (requiring I/O) page faults: 0
Minor (reclaiming a frame) page faults: 36025
Voluntary context switches: 13
Involuntary context switches: 191
Swaps: 0
File system inputs: 0
File system outputs: 0
Socket messages sent: 0
Socket messages received: 0
Signals delivered: 0
Page size (bytes): 4096
Exit status: 0

[mmd-osm]

I had some issues to apply this PR cleanly, although Github claims that everything is fine. I think this a side effect of the most recent std:: additions across the whole source code. Can you merge the current master and update the pr? thanks!

[tyrasd]

although Github claims that everything is fine

I think that was simply because the PR was requested against the minor_issues branch. I've changed it to master now and am looking into the conflicts.

[tyrasd]

should be resolved now

[mmd-osm]

fyi: I deployed your patch on the following endpoint: http://dev.overpass-api.de/api_mmd/

[mmd-osm]

This one got superseded by dba448f -> this pull request can be closed, there's nothing left to do.