Re: pgsql: Change CRCs in WAL records from 64bit to 32bit

I have trimmed TODO.detail to remove the completed items.

---------------------------------------------------------------------------

Tom Lane wrote:
> Log Message:
> -----------
> Change CRCs in WAL records from 64bit to 32bit for performance reasons.
> Instead of a separate CRC on each backup block, include backup blocks
> in their parent WAL record's CRC; this is important to ensure that the
> backup block really goes with the WAL record, ie there was not a page
> tear right at the start of the backup block. Implement a simple form
> of compression of backup blocks: drop any run of zeroes starting at
> pd_lower, so as not to store the unused 'hole' that commonly exists in
> PG heap and index pages. Tweak PageRepairFragmentation and related
> routines to ensure they keep the unused space zeroed, so that the above
> compression method remains effective. All per recent discussions.
>
> Modified Files:
> --------------
> pgsql/src/backend/access/nbtree:
> nbtpage.c (r1.84 -> r1.85)
> (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/nbtree/nbtpage.c.diff?r1=1.84&r2=1.85)
> nbtxlog.c (r1.20 -> r1.21)
> (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/nbtree/nbtxlog.c.diff?r1=1.20&r2=1.21)
> pgsql/src/backend/access/transam:
> xlog.c (r1.194 -> r1.195)
> (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/transam/xlog.c.diff?r1=1.194&r2=1.195)
> pgsql/src/backend/storage/page:
> bufpage.c (r1.63 -> r1.64)
> (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/storage/page/bufpage.c.diff?r1=1.63&r2=1.64)
> pgsql/src/backend/utils/hash:
> pg_crc.c (r1.12 -> r1.13)
> (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/hash/pg_crc.c.diff?r1=1.12&r2=1.13)
> pgsql/src/bin/pg_controldata:
> pg_controldata.c (r1.23 -> r1.24)
> (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_controldata/pg_controldata.c.diff?r1=1.23&r2=1.24)
> pgsql/src/bin/pg_resetxlog:
> pg_resetxlog.c (r1.32 -> r1.33)
> (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_resetxlog/pg_resetxlog.c.diff?r1=1.32&r2=1.33)
> pgsql/src/include/access:
> xlog.h (r1.61 -> r1.62)
> (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/access/xlog.h.diff?r1=1.61&r2=1.62)
> xlog_internal.h (r1.6 -> r1.7)
> (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/access/xlog_internal.h.diff?r1=1.6&r2=1.7)
> pgsql/src/include/catalog:
> pg_control.h (r1.21 -> r1.22)
> (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_control.h.diff?r1=1.21&r2=1.22)
> pgsql/src/include/utils:
> pg_crc.h (r1.12 -> r1.13)
> (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/pg_crc.h.diff?r1=1.12&r2=1.13)
>
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