Thread

1. One store, two machines?

   Michael R. Jinks <mjinks@uchicago.edu> — 2000-07-26T06:39:27Z

   Greetings.
   
   We would like to implement a PostgreSQL database in such a way that the data
   are housed on disk volumes which are redundant across two Solaris (or maybe
   Linux) hosts.  Both hosts must have write access to the store -- a master
   system/backup system scheme is not acceptable for us; was also want this to
   be a load balancing setup.
   
   Does Postgres have a facility for keeping data stores on two hosts in sync?
   
   TIA,
   -m
   -- 
   Michael Jinks, IB
   Systems Administrator, CCCP
   finger mjinks@embley.spc.uchicago.edu for public key
   A guiding voice for all humanity: http://www.yellow5.com/pokey/
   
   

2. Too many clients - Error

   FMK <meyer-kassel@online-shop-ag.de> — 2000-07-26T10:20:11Z

   Hi out there.
   
   Since this morning I'm getting this error when I try to connect to our DB-Server:
   
   Sorry, too many clients already
   
   
   What does that mean ? Where can I set this limit ? What's the cause for this
   error ? I didn't have this before...
   
   
   Greetings
   
   /FMK
   
   
   
   

3. Re: Too many clients - Error

   John McKown <jmckown@prodigy.net> — 2000-07-26T11:07:33Z

   On Wed, 26 Jul 2000, Florian Meyer-Kassel wrote:
   
   > Hi out there.
   > 
   > Since this morning I'm getting this error when I try to connect to our
   > DB-Server:
   > 
   > Sorry, too many clients already
   > 
   > 
   > What does that mean ? Where can I set this limit ? What's the cause for this
   > error ? I didn't have this before...
   > 
   
   PostgreSQL as normally distributed only allows 32 concurrent users. You
   have exceeded this number of users. You can fix this in one of two ways.
   The hard way is to reconfigure & recompile PostgreSQL using the
   --with-maxbackends=1024 (maximum number of users is 1024!). The simple way
   is to edit the PostgreSQL startup script to include the parameter
    "-N 1024" to set the maximum number of concurrent connections to 1024.
   
   I don't see any command to list who is currently using PostgreSQL.
   
   Hope this helps some,
   John
   
   
   

4. Re: One store, two machines?

   D. Duccini <duccini@backpack.com> — 2000-07-26T14:02:09Z

   Yeah, its called RAID ;)
   
   seriously, consider using a Mylex external controller that has twin SCSI
   bus interfaces on it that allows for multiple hosts
   
   the other option would be to write a trigger mechanism implemented in the
   database to do the writes
   
   On Wed, 26 Jul 2000, Michael R. Jinks wrote:
   
   > Greetings.
   > 
   > We would like to implement a PostgreSQL database in such a way that the data
   > are housed on disk volumes which are redundant across two Solaris (or maybe
   > Linux) hosts.  Both hosts must have write access to the store -- a master
   > system/backup system scheme is not acceptable for us; was also want this to
   > be a load balancing setup.
   > 
   > Does Postgres have a facility for keeping data stores on two hosts in sync?
   > 
   > TIA,
   > -m
   > -- 
   > Michael Jinks, IB
   > Systems Administrator, CCCP
   > finger mjinks@embley.spc.uchicago.edu for public key
   > A guiding voice for all humanity: http://www.yellow5.com/pokey/
   > 
   
   
   -----------------------------------------------------------------------------
   david@backpack.com            BackPack Software, Inc.        www.backpack.com
   +1 651.645.7550 voice       "Life is an Adventure.    
   +1 651.645.9798 fax            Don't forget your BackPack!"   
   -----------------------------------------------------------------------------
   
   
   

5. Re: Too many clients - Error

   Tom Lane <tgl@sss.pgh.pa.us> — 2000-07-26T14:36:57Z

   John McKown <jmckown@prodigy.net> writes:
   > PostgreSQL as normally distributed only allows 32 concurrent users. You
   > have exceeded this number of users. You can fix this in one of two ways.
   > The hard way is to reconfigure & recompile PostgreSQL using the
   > --with-maxbackends=1024 (maximum number of users is 1024!). The simple way
   > is to edit the PostgreSQL startup script to include the parameter
   >  "-N 1024" to set the maximum number of concurrent connections to 1024.
   
   Note you will also need to increase -B (to at least twice -N).
   
   It may be a bad idea to raise the limit as far as 1024, unless your
   platform is really configured to support that many active backends
   (which means LOTS of RAM and swap space, lots of kernel open-file-table
   entries, etc).  The reason the default is 32 is that that roughly
   corresponds to the factory-stock limits in many Unixen about size of
   shared memory blocks and so forth.  Don't be surprised if you have to
   rejigger kernel parameter settings before you can go up very far.
   
   > I don't see any command to list who is currently using PostgreSQL.
   
   "ps -aux | grep postgres" (adapt to local situation...)
   
   			regards, tom lane