Quote from: molecular on March 27, 2014, 06:26:22 PM

Quote from: John Tobey on March 25, 2014, 07:33:44 PM

Quote from: molecular on March 25, 2014, 06:26:42 PM

I have a question about mempool transactions regarding performance:

So I'm running http://blockexplorer.auroracoin.eu and because I have allocated quite a machine to the task everything has been zappy and fine this morning.

However when I checked back from work an hour later I saw loads of exceptions saying "error: [Errno 32] Broken pipe", the nginx I have in front reporting gateway timeouts. I'm hypothesizing the db queries are the bottleneck.

I tried rebuilding the database (drop it completely and rebuild)... that didn't help, it started again right away.

There are loads of mempool transactions in AURoracoin because we're being pool-hopping-attacked to the point where there hasn't been a block for 6 hours or so.

Another instance I run with same setup, but on quite weak machine (vm) was able to cope with the load quite well and didn't suffer broken pipes.

What fixed it was to re-initialize BOTH the blockchain of the AuroraCoind AND the db (just db didn't help).

Now the question: how are mempool transactions handled and could the existance of many mempool transactions have considerable impact on db (or abe.py) performance?

I'm a bit confused... does anyone have an idea what could've been causing this?

It could be transactions being left open, suboptimal SQL, or Huh

If you have a collection of Python stack traces or database process lists from during the timeouts, they might point to the offender(s).

This is the error


Exception happened during processing of request from ('178.63.69.203', 49828)
Traceback (most recent call last):
  File "/usr/lib/python2.7/SocketServer.py", line 295, in _handle_request_noblock
    self.process_request(request, client_address)
  File "/usr/lib/python2.7/SocketServer.py", line 321, in process_request
    self.finish_request(request, client_address)
  File "/usr/lib/python2.7/SocketServer.py", line 334, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "/usr/lib/python2.7/SocketServer.py", line 651, in __init__
    self.finish()
  File "/usr/lib/python2.7/SocketServer.py", line 704, in finish
    self.wfile.flush()
  File "/usr/lib/python2.7/socket.py", line 303, in flush
    self._sock.sendall(view[write_offset:write_offset+buffer_size])
error: [Errno 32] Broken pipe

(I think nginx (load-balancing here) or the client times out because it's taking too long)

on AuroraCoind debug.log I see this:


 22478  ThreadRPCServer method=getrawtransaction
 22479  ThreadRPCServer method=getrawtransaction
 22480  ThreadRPCServer method=getrawtransaction
 22481  ThreadRPCServer method=getrawtransaction
 22482  ThreadRPCServer method=getrawtransaction
 22483  ThreadRPCServer method=getrawtransaction
 22484  ThreadRPCServer method=getrawtransaction
 22485  ThreadRPCServer method=getrawtransaction
 22486  ThreadRPCServer method=getrawtransaction
 22487  ThreadRPCServer method=getrawtransaction
 22488  ThreadRPCServer method=getrawtransaction
 22489  ThreadRPCServer method=getrawtransaction
 22490  ThreadRPCServer method=getrawtransaction
 22491  ThreadRPCServer method=getrawtransaction
 22492  ThreadRPCServer method=getrawtransaction
 22493  ThreadRPCServer method=getrawtransaction
 22494  ThreadRPCServer method=getrawtransaction
 22495  ThreadRPCServer method=getrawtransaction
 22496  ThreadRPCServer method=getrawtransaction
 22497  ThreadRPCServer method=getrawtransaction
 22498  ThreadRPCServer method=getrawtransaction
 22499  ThreadRPCServer method=getrawtransaction
 22500  ThreadRPCServer method=getrawtransaction
 22501  ThreadRPCServer method=getrawtransaction
 22502  ThreadRPCServer method=getrawtransaction
 22503  ThreadRPCServer method=getrawtransaction
 22504  ThreadRPCServer method=getrawtransaction

about 500 per seconds

psql> select * from pg_stat_activity;

reports only one IDLE connection

This is what I get after block with a lot of tranasactions:

Code:

/usr/local/lib/python2.7/dist-packages/Abe/abe.py in handle_chain(abe=<__main__.Abe instance>, page={'body': ['

Search by address, block .........}, 'title': u'AuroraCoin'})
   486 seconds = int(seconds)
   487 satoshis = int(satoshis)
=> 488 ss = int(ss)
   489 total_ss = int(total_ss)
   490
ss = None, builtin int =