Re: Looking for the Oracle equivalent to MS SQL Server timestamp field

There might be internal latches with sysguid and thus generating a lot of inserts at one time might cause a lot of latch contention. Whereas a cached sequence might be more efficient on the insert. Insert speed might be important if you have a sufficiently high transaction rate. Jim
"Donovan R." <mdonovan_at_hotmail.com> wrote in message news:gmv55v0p2734a02ieva1kkn1cjs2rmuvk5_at_4ax.com...
> Maybe you right. I said that because thinking to a reason to use a
> reverse index on a generated key like a sequence. The key is reversed
> to break the tree, so the index became more selective.
> By example having 10000 number key who start by 1234 at the first
> branch level. Oracle have to scan all these entries before passing to
> next branch. But having a completely random number like a sysquid
> assure you a direct access.
>
> I don't see your point about caching sequences. The insert was never a
> problem, can be done on schedule. The performance issue is always on
> data retrieval.
>
> On Wed, 19 Feb 2003 03:31:01 GMT, "Jim Kennedy"
> <kennedy-downwithspammersfamily_at_attbi.com> wrote:
>
> >I don't think an index on a sysguid will be faster. The key will be
 larger
> >(a lot larger) and it doesn't make sense that it would be faster. In
> >addition, inserting 1,000 rows each with a cached sequence is probably
> >faster than 1,000 rows of sysguid.
> >
> >Jim
> >"Donovan R." <mdonovan_at_hotmail.com> wrote in message
> >news:eis55vg4du05gd4dps9pi3bvh12nk707hk_at_4ax.com...
> >> try sysguid.
> >>
> >> Some people will recommend using sequences. A completly random number
> >> like sysguid (Oracle claims that the generated number will be unique
> >> on universe not only on your federation of servers) is more efficient
> >> for a b-tree index(less branches), so even if the sysguid is a raw
> >> data (is bigger than a number) the index will be fastest finally.
> >>
> >>
> >> On 18 Feb 2003 11:36:24 -0800, aguptill_at_nxtrend.com (Arch) wrote:
> >>
> >> >I'm looking for the Oracle data type and possibly method to shadow the
> >> >MS SQL Server timestamp data type.
> >> >
> >> >From SQL Server Online help a timestamp is defined as:
> >> >timestamp is a data type that exposes automatically generated binary
> >> >numbers, which are guaranteed to be unique within a database.
> >> >timestamp is used typically as a mechanism for version-stamping table
> >> >rows. The storage size is 8 bytes.
> >> >
> >> >I'm not necessarily concernd that the datatype stays binary but the
> >> >funcationality is what I'm after. In particular is the notion of
> >> >ensuring that I can tell if a record has been updated since the data
> >> >was pulled that I'm now working with and possibly updating back to the
> >> >db system.
> >> >
> >> >Thanks in advance.
> >> >Arch
> >>
> >
>
Received on Wed Feb 19 2003 - 06:01:29 CET