ConcernedOfTunbridgeWells

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bio website maps.google.co.uk/…
location London, United Kingdom
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visits member for 3 years, 1 month
seen 13 hours ago

Data warehouse contractor in London. Mostly I work with SQL Server on Insurance clients. I've proposed a business intelligence site on Area 51, which has now been merged into dba.stackexchange.com.


Jun
26
comment What is a good/healthy mysql query execution time?
Take a look at the query plans and then estimate the I/O needed to satisfy each query. For a small number of queries this shouldn't be too hard. Then (under load) look at the disk buffer cache hit rate and tune the DBMS accordingly if necessary. On a modern server you should be able to get buffer cache hit rate percentages in the high 90's. Apply that to your reads. Make an estimate of your write traffic. That should give you a back-of-fag-packet IOPS figure.
Jun
26
comment What is a good/healthy mysql query execution time?
The question is somewhat vague. Take a look at the answer below for some suggestions as to where to start.
Jun
26
answered What is a good/healthy mysql query execution time?
Jun
10
awarded  Yearling
May
5
comment Database design for handling 1 billion rows and counting
Are you inserting the data row-by-row or using batched bulk inserts?
Apr
17
revised A rollback on a production server that's been running too long
deleted 6 characters in body
Apr
8
comment Is Oracle more demanding environment for a DBA than SQL Server?
@gbn - they let me do Oracle DBA work at one point.
Apr
5
comment Import 10 Billion Rows, Daily
in that case you might want to pre-process the field, parse out the data you want and punt the fluff. This could be done off-line before loading it into the database.
Apr
5
comment Import 10 Billion Rows, Daily
You might also want to run multiple bulk insert tasks in parallel. Scalzo's The Oracle DBA guide to data warehousing and star schemas discusses a technique for doing this on Oracle and its bulk load tool (SQL*Loader). You could do something similar with a .net wrapper that can spawn multiple processes.
Apr
5
comment Import 10 Billion Rows, Daily
The varchars would only be that big if they were free text. I can't imagine anyone keying 10 billion free text fields into anything on a daily basis, so they're much more likely to be alphabetic or alphanumeric codes, and probably only a few bytes long each.
Mar
8
awarded  Nice Answer
Mar
6
comment PostgreSQL designing tool
See This reply from a vendor representative for a good example of how a vendor can contribute an answer of this type.
Mar
3
awarded  Good Answer
Jan
29
comment How recording of every change of a row in a database is generaly stored?
For 1000 tables you write a utlity that reads the definitions from the system data dictionary and generates the triggers and table definitions. I've done it on a system with 560 tables and it works just fine.
Jan
19
reviewed Approve suggested edit on Can't connect to local Postgres databases
Dec
21
awarded  Necromancer
Dec
1
reviewed Approve suggested edit on Does MySQL cache queries?
Nov
28
awarded  Good Answer
Nov
26
reviewed Approve suggested edit on DDL trigger AFTER ALTER ON SCHEMA behavior
Nov
25
reviewed Approve suggested edit on How to set up simple database replication using WAMP server?