Thread: How many no. of clients can access database simultaneously?
Hi, Here I have some queries on which I didn't get document. Please help me. Thanks in advance. 1: How many maximum number of clients can access the same database at a time? 2: What is the recovery mechanism provided for PostgreSQL? Is there any provision for comma separated records or file? 3: Are there any interfaces provided in C/C++ to change or set the DATESTYLE and TIMESTAMP? 4: When client accesses the database from other host machine, we provide the ipaddress and hostname for connection. My questionis about, priority is given to which parameter for connecting to the remote host, ipaddress or hoatname, which is having highest priority? 5: What type of the connection exits when client connects to remote database server? Is that TCP or UDP? 6: Is there any provision for database spaaning on multiple diska? 7: How the database recovery is provided in case if the connection between the client and server breaks while the transactionis in process and client & server are on separate machines/hosts? Once again thanks in advance, Namrata.
> Here I have some queries on which I didn't get document. Please help me. Thanks in advance. > > 1: How many maximum number of clients can access the same database at a time? It depends on a lot of things. Hardware/OS configuration being at the top of the list. I'm sure there is no hard coded limit to the number of connections in PG so it's what ever your machine can support. > 2: What is the recovery mechanism provided for PostgreSQL? Is there any provision for comma separated records or file? Aside from the WAL log, you can dump databases to flat files for later import. > 3: Are there any interfaces provided in C/C++ to change or set the DATESTYLE and TIMESTAMP? DATESTYLE can be set through an environment variable or SET in a PG session (I think). > 4: When client accesses the database from other host machine, we provide the ipaddress and hostname for connection. My question is about, priority is > given to which parameter for connecting to the remote host, ipaddress or hoatname, which is having highest priority? Huh? How are you providing both? > 5: What type of the connection exits when client connects to remote database server? Is that TCP or UDP? TCP > 6: Is there any provision for database spaaning on multiple diska? I would think this would be more of an operating system's job but PG stores databases in directories on the file system, I guess if those directories were mounted on different disks it would work -- *shrug* don't take my word for it though. > 7: How the database recovery is provided in case if the connection between the client and server breaks while the transaction is in process and client > & server are on separate machines/hosts? I assume that the transaction rolls back. -Mitch
Namrata writes: > 1: How many maximum number of clients can access the same database at a time? The compiled-in default is 1024, the run-time default is 32. Both can be changed to a couple of million if you have the memory. (Not that an OS will usually support that many processes.) > 2: What is the recovery mechanism provided for PostgreSQL? Is there any provision for comma separated records or file? Make regular backups. ;-) > 3: Are there any interfaces provided in C/C++ to change or set the DATESTYLE and TIMESTAMP? No, but there's an SQL interface that you can call from C or C++. > 4: When client accesses the database from other host machine, we provide the ipaddress and hostname for connection. Myquestion is about, priority is > given to which parameter for connecting to the remote host, ipaddress or hoatname, which is having highest priority? IP address > 5: What type of the connection exits when client connects to remote database server? Is that TCP or UDP? TCP > 6: Is there any provision for database spaaning on multiple diska? Not within PostgreSQL, but you can use a logical volumen manager in your operating system. > 7: How the database recovery is provided in case if the connection between the client and server breaks while the transactionis in process and client > & server are on separate machines/hosts? Transaction is rolled back. -- Peter Eisentraut peter_e@gmx.net http://funkturm.homeip.net/~peter