New server to improve performance on our large and busy DB - advice?

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



My client just informed me that new hardware is available for our DB server.

. Intel Core 2 Quads Quad
. 48 GB RAM
. 4 Disk RAID drive (RAID level TBD)

I have put the ugly details of what we do with our DB below, as well as the postgres.conf settings. But, to summarize: we have a PostgreSQL 8.3.6 DB with very large tables and the server is always busy serving a constant stream of single-row UPDATEs and INSERTs from parallel automated processes.

There are less than 10 users, as the server is devoted to the KB production system.

My questions:

1) Which RAID level would you recommend
2) Which Windows OS would you recommend? (currently 2008 x64 Server)
3) If we were to port to a *NIX flavour, which would you recommend? (which support trouble-free PG builds/makes please!)
4) Is this the right PG version for our needs?

Thanks,

Carlo

The details of our use:

. The DB hosts is a data warehouse and a knowledgebase (KB) tracking the professional information of 1.3M individuals.
. The KB tables related to these 130M individuals are naturally also large
. The DB is in a perpetual state of serving TCL-scripted Extract, Transform and Load (ETL) processes
. These ETL processes typically run 10 at-a-time (i.e. in parallel)
. We would like to run more, but the server appears to be the bottleneck
. The ETL write processes are 99% single row UPDATEs or INSERTs.
. There are few, if any DELETEs
. The ETL source data are "import tables"
. The import tables are permanently kept in the data warehouse so that we can trace the original source of any information.
. There are 6000+ and counting
. The import tables number from dozens to hundreds of thousands of rows. They rarely require more than a pkey index. . Linking the KB to the source import date requires an "audit table" of 500M rows, and counting. . The size of the audit table makes it very difficult to manage, especially if we need to modify the design. . Because we query the audit table different ways to audit the ETL processes decisions, almost every column in the audit table is indexed. . The maximum number of physical users is 10 and these users RARELY perform any kind of write
. By contrast, the 10+ ETL processes are writing constantly
. We find that internal stats drift, for whatever reason, causing row seq scans instead of index scans. . So far, we have never seen a situation where a seq scan has improved performance, which I would attribute to the size of the tables . We believe our requirements are exceptional, and we would benefit immensely from setting up the PG planner to always favour index-oriented decisions - which seems to contradict everything that PG advice suggests as best practice.

Current non-default conf settings are:

autovacuum = on
autovacuum_analyze_scale_factor = 0.1
autovacuum_analyze_threshold = 250
autovacuum_naptime = 1min
autovacuum_vacuum_scale_factor = 0.2
autovacuum_vacuum_threshold = 500
bgwriter_lru_maxpages = 100
checkpoint_segments = 64
checkpoint_warning = 290
datestyle = 'iso, mdy'
default_text_search_config = 'pg_catalog.english'
lc_messages = 'C'
lc_monetary = 'C'
lc_numeric = 'C'
lc_time = 'C'
log_destination = 'stderr'
log_line_prefix = '%t '
logging_collector = on
maintenance_work_mem = 16MB
max_connections = 200
max_fsm_pages = 204800
max_locks_per_transaction = 128
port = 5432
shared_buffers = 500MB
vacuum_cost_delay = 100
work_mem = 512MB



--
Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance

[Postgresql General]     [Postgresql PHP]     [PHP Users]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Books]     [PHP Databases]     [Yosemite]

  Powered by Linux