Обсуждение: connectivity to database been an issue for me.
Hi,
We are in development stage of implementing postgres.
Our data center is in Tampa and we are in Bardenton and I am using DSL at my office (384 up, 1.5 down).
Data center is 2 meg ea way.
When I use pgadmin to connect it is ok, but as soon as I do any querry that has much data I get disconeected.
I was able to test pinging an outside web page (yahoo.com) and could see as soon as I start the transimission from a query in pgadmin the pinging gets disrupted (also I lose the connection to pgadmin).
I am thinking of T1 to data center (but is like 600 a month) or even upping the office to breakfreee which is pretty cheap and is 2 mb ea way.
Before I spend $ I thought I would ask if there are any tools less subject to disconnect from temporary connection loss?
If any one else experienced the same type of issues and what they did to resolve the issue.
Once we go live I am probably going to want replication and if the connection is going to thwart this I need to see if there is a workable solution.
Joel Fradkin
On Wed, 2005-03-30 at 10:41, Joel Fradkin wrote: > Hi, > > > > We are in development stage of implementing postgres. > > Our data center is in Tampa and we are in Bardenton and I am using DSL > at my office (384 up, 1.5 down). > > Data center is 2 meg ea way. > > When I use pgadmin to connect it is ok, but as soon as I do any querry > that has much data I get disconeected. You've got a networking problem, not postgresql, I'd bet. Do the logs on the server show anything odd, like crashing backends?
You've got a networking problem, not postgresql, I'd bet. Do the logs on the server show anything odd, like crashing backends? I do not see any crashes and when connected from inside the data center I don't have any issues. Times I see an issue are when we pump any data (large result set, restore, etc) over the DSL connection the ping to inside the data center or just to a public site like yahoo starts to time out. So I am guessing I am losing connectivity from my development site (using verizon DSL). I use the same connection to my current data center running MSSQL and have experienced some issue, but nothing like I get with PGadmin. I have seen using enterprise manager doing work I occasionally see it drop the connection. I am not suggesting this is a postgres issue, I believe it is when the pipe is over the 1.5 down or 394 up I lose connection (should happen if it is a pcanywhere transfer, ftp, sql data set etc.). But I will say I do not seem to get disconnected from MSSQL using enterprise manager very often, while I get disconnected from pgadmin every time I ask for large data set. This might be because the postgres is on a much faster box and is pumping more data. But the question is two items. 1. Is there a posgres admin tool not so fussy about connection (re-connects automatically if its just a blip in connectivity; like a ping timing out is just one ping several are fine then blip time out, back to fine for 6 or 7 pings then blip time out.)? 2. does anyone have experience with this type of issue, will getting either 2 mb connectivity with breakfree, or a point to point T1 to the data center help with losing connectivity when larger data sets are requested. My main concern is with getting replication set up and if this issue will have a disasterous effect on trying to establish that.
Joel Fradkin writes: > Hi, > > > > We are in development stage of implementing postgres. > > Our data center is in Tampa and we are in Bardenton and I am using DSL at my > office (384 up, 1.5 down). > > Data center is 2 meg ea way. > > When I use pgadmin to connect it is ok, but as soon as I do any querry that > has much data I get disconeected. > > I was able to test pinging an outside web page (yahoo.com) and could see as > soon as I start the transimission from a query in pgadmin the pinging gets > disrupted (also I lose the connection to pgadmin). > > > > I am thinking of T1 to data center (but is like 600 a month) or even upping > the office to breakfreee which is pretty cheap and is 2 mb ea way. > > Before I spend $ I thought I would ask if there are any tools less subject > to disconnect from temporary connection loss? > > If any one else experienced the same type of issues and what they did to > resolve the issue. > As others already pointed out, this is likely to be a networking problem that has nothing to do with postgresql. What comes in my mind regarding DSL is that a common error is to use a too large MTU. Since there is some repackaging of network packets in the ppp over ethernet protocol, one needs to make sure that the raw packages are small enough to allow for the overhead. Otherwise the effect is, that small packages (e.g. your ping) pass, while large packages hang the connection. Don't ask me for details of the configuration, I do that ~ once every two years (on linux). Morus
Well the issue seems to occur for any traffic not limited to any one machine. Pinging Yahoo for instance the ping is timing out when the line gets full load. I spoke to Verizon and they admitted they sold more bandwidth then the hard wires in the area support. I am going to see if we can slow down the traffic at the fire wall, but also plan on getting a 2mb breakfree wireless account as it is just 100.00 a month and much better connectivity. My real question was if it would be better to get a T1 to the data center or if going over the internet was ok if I get the expanded bandwidth; based on real world experience doing a similar thing. I hate to recommend an expensive solution just to end up with the same issues. I tried loading the line with various types of communication to different machines, so it is not a postgres issue at all (sorry for voicing the question in a pg forum, but I figured you guys deal with a bit of the networking as well). Unfortunatley the T1 is a bit expensive (T1>500.00 a month). Joel Fradkin -----Original Message----- From: Morus Walter [mailto:morus.walter@tanto.de] Sent: Thursday, March 31, 2005 3:12 AM To: pgsql-admin@postgresql.org; Joel Fradkin Subject: Re: [ADMIN] connectivity to database been an issue for me. Joel Fradkin writes: > Hi, > > > > We are in development stage of implementing postgres. > > Our data center is in Tampa and we are in Bardenton and I am using DSL at my > office (384 up, 1.5 down). > > Data center is 2 meg ea way. > > When I use pgadmin to connect it is ok, but as soon as I do any querry that > has much data I get disconeected. > > I was able to test pinging an outside web page (yahoo.com) and could see as > soon as I start the transimission from a query in pgadmin the pinging gets > disrupted (also I lose the connection to pgadmin). > > > > I am thinking of T1 to data center (but is like 600 a month) or even upping > the office to breakfreee which is pretty cheap and is 2 mb ea way. > > Before I spend $ I thought I would ask if there are any tools less subject > to disconnect from temporary connection loss? > > If any one else experienced the same type of issues and what they did to > resolve the issue. > As others already pointed out, this is likely to be a networking problem that has nothing to do with postgresql. What comes in my mind regarding DSL is that a common error is to use a too large MTU. Since there is some repackaging of network packets in the ppp over ethernet protocol, one needs to make sure that the raw packages are small enough to allow for the overhead. Otherwise the effect is, that small packages (e.g. your ping) pass, while large packages hang the connection. Don't ask me for details of the configuration, I do that ~ once every two years (on linux). Morus
On Thu, 2005-03-31 at 08:00, Joel Fradkin wrote: > Well the issue seems to occur for any traffic not limited to any one > machine. > > Pinging Yahoo for instance the ping is timing out when the line gets full > load. > I spoke to Verizon and they admitted they sold more bandwidth then the hard > wires in the area support. > > I am going to see if we can slow down the traffic at the fire wall, but also > plan on getting a 2mb breakfree wireless account as it is just 100.00 a > month and much better connectivity. > > My real question was if it would be better to get a T1 to the data center or > if going over the internet was ok if I get the expanded bandwidth; based on > real world experience doing a similar thing. I hate to recommend an > expensive solution just to end up with the same issues. I tried loading the > line with various types of communication to different machines, so it is not > a postgres issue at all (sorry for voicing the question in a pg forum, but I > figured you guys deal with a bit of the networking as well). > > Unfortunatley the T1 is a bit expensive (T1>500.00 a month). My recommendation is to make Verizon fix the problem with the DSL. It should work, period. Assuming the problem is NOT in your configuration, but in theirs, this is their problem, and until they fix it, they should not be paid. I'd tell them to fix it and call you when they're done. I had a machine on DSL in Colorado for about 6 years, and for the first 6 months USWest (now qwest) had constant routing issues pop up. I just picked up the phone about once a week and stayed on the 1-800 line for an hour at a time while they fixed it. Eventually, things settled down and it was a rock solid stable connection for most of the rest of that time. You shouldn't have to pay $500.00 a month just to get a working connection.
On Thu, Mar 31, 2005 at 10:11:53 +0200, Morus Walter <morus.walter@tanto.de> wrote: > > What comes in my mind regarding DSL is that a common error is to use > a too large MTU. Since there is some repackaging of network packets in > the ppp over ethernet protocol, one needs to make sure that the raw packages > are small enough to allow for the overhead. You can get DSL that doesn't use PPPoE.
I just spent some time with Verizon and we will see if they can fix, or if I have to find a new provider. I will try that prior to point to point (although the point to point may be a good option too if all else fails). Thanks everyone for the ideas and helping get a clear perspective on the issue. Joel Fradkin head. You can get DSL that doesn't use PPPoE.