Oracle Heap Tables or SQL Server Clustered Indexes? Jonathan Lewis and Grant Fritchey Live Debate

Jonathan Lewis on 30 April 2012 with 0 comments

This webinar is being broadcast by Red Gate on 7 June 2012. Oracle and SQL Server may both share a common language, but certain things are handled quite differently. Jonathan Lewis (OakTable Network, Oracle Ace Director) is used to seeing heap tables (almost) everywhere, but Grant Fritchey (Microsoft SQL Server MVP) is used to seeing clustered indexes (almost) everywhere. But… Continue Reading →

Session SQL

Jonathan Lewis on 17 February 2012 with 0 comments

From time to time a request for a query to “show the current SQL” for each session appears on the internet. It’s not really difficult to write something suitable, but this particular request is an interesting demonstration of how much inertia there is in the Oracle world. Here’s a recent suggestion of what the query should look like: select sess.sid,… Continue Reading →

Indexes are Tables

Jonathan Lewis on 16 December 2011 with 3 comments

Oracle’s optimizer has many strategies for acquiring the data you want with the minimum of work. Some of these strategies are really quite subtle and sophisticated – think of the Star Transformation, for example, which uses a two-phase approach to dimension tables; or the Index Join which does hash joins between indexes to avoid visiting tables. Despite all the clever things… Continue Reading →

Deadlock

Jonathan Lewis on 08 September 2011 with 0 comments

From Jonathan Lewis’ Oracle Scratchpad blog. Here’s a deadlock graph that appeared on Oracle-L and OTN a couple of days ago: Deadlock graph: ———Blocker(s)——– ———Waiter(s)——— Resource Name process session holds waits process session holds waits TX-001a0002-0002a0fe 196 197 X 166 1835 S TM-0000c800-00000000 166 1835 SX 196 197 SX SSX It’s a little unusual because instead of the common TX… Continue Reading →