Greg Stark <[EMAIL PROTECTED]> wrote:
> The plan Gavin Sherry and I were discussing at the Code Sprint was to store a
> single "most common xmin" xmin in the per-page special area. Then have a bit
> on each tuple indicating that the xmin isn't present in the tuple and instead
> to use the xmin from the page footer. Any tuples with other values of xmin
> would have to store that xmin normally.
Is this a similar approach to Interested Transaction List (ITL) in Oracle?
http://www.dbazine.com/oracle/or-articles/nanda3
ITL-like approach is more efficient than per-tuple XIDs
unless all tuples in a page are locked at the same time.
However, MAXTRANS and PCTFREE issues may bother us.
Regards,
---
ITAGAKI Takahiro
NTT Open Source Software Center
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TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
