ON.KG wrote:
Hi All!
What is faster - SLECTion data from one large table (200 000 - 300 000
records), or SELECTion from a few small tables (example, 2 tables 150
000 records each)?
RH> It depends. Are you selecting all records? One record? A few records? If
RH> one or a few, do you have a suitable index on the table(s)? Is the table
RH> clustered? Expected to be cached in RAM?
RH> Do you have a specific problem, or reason to believe you may encounter one?
It's a real problem
For example i have two large tables
Structure of tables is same - has two fields - id, ip
Now i'm using two selection from each in one transaction
Each of them selects only one record
selection clase like WHERE ip = 'xxx.xxx.xxx.xxx'
so it is searches existance of IP in each table
tables are clustered
OK - so the tables aren't updated frequently, I assume. Do you have an
index on "ip"?
about cached in RAM - i'm novice in Postgresql - how does it work?
The operating-system will keep frequently used disk-blocks in memory.
You don't have to do anything. Have you done any performance tuning in
your postgresql.conf file? If not, try reading:
http://www.powerpostgresql.com/PerfList
now i need to make much faster as it is possible
and have an idea just merge two tables in one - will it help me?
If they hold the same information, they probably shouldn't have been
split in the first place.
--
Richard Huxton
Archonet Ltd
---------------------------(end of broadcast)---------------------------
TIP 5: Have you checked our extensive FAQ?
http://www.postgresql.org/docs/faq
