Thread: pgsql: Replace the KnownAssignedXids hash table with a sorted-array data

Log Message:
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Replace the KnownAssignedXids hash table with a sorted-array data structure,
and be more tense about the locking requirements for it, to improve performance
in Hot Standby mode.  In passing fix a few bugs and improve a number of
comments in the existing HS code.

Simon Riggs, with some editorialization by Tom

Modified Files:
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    pgsql/src/backend/access/transam:
        twophase.c (r1.60 -> r1.61)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/transam/twophase.c?r1=1.60&r2=1.61)
    pgsql/src/backend/storage/ipc:
        procarray.c (r1.66 -> r1.67)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/storage/ipc/procarray.c?r1=1.66&r2=1.67)