pgsql: hash: Refactor and clean up bucket split code.

hash: Refactor and clean up bucket split code.

As with commit 30df93f698d016d086e8961aa6c6076b37ea0ef4 and commit
b0f18cb77f50a54e997d857d592f6a511617f52c, the goal here is to move all
of the related page modifications to a single section of code, in
preparation for adding write-ahead logging.

Amit Kapila, with slight changes by me. The larger patch series of
which this is a part has been reviewed and tested by Álvaro Herrera,
Ashutosh Sharma, Mark Kirkwood, Jeff Janes, and Jesper Pedersen.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/21a3cf41284c08307ef9abe3400be5dc53723519

Modified Files
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src/backend/access/hash/hashpage.c | 160 ++++++++++++++++---------------------
1 file changed, 67 insertions(+), 93 deletions(-)