pgsql-server: Update item: < * Implement dirty reads or shared row

Log Message:
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Update item:

< * Implement dirty reads or shared row locks and use them in RI triggers (?)

* Implement dirty reads or shared row locks and use them in RI triggers

Adding shared locks requires recording the table/rows numbers in a
shared area, and this could potentially be a large amount of data.
One idea is to store the table/row numbers in a separate table and set
a bit on the row indicating looking in this new table is required to
find any shared row locks.

Modified Files:
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pgsql-server/doc:
TODO (r1.1342 -> r1.1343)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/doc/TODO.diff?r1=1.1342&amp;r2=1.1343)