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Introduce 64-bit hash functions with a 64-bit seed.

This will be useful for hash partitioning, which needs a way to seedthe hash functions to avoid problems such as a hash index on a hashpartitioned table clumping all values into a small portion of thebucket space; it's also useful for anything that wants a 64-bit hashvalue rather than a 32-bit hash value.Just in case somebody wants a 64-bit hash value that is compatiblewith the existing 32-bit hash values, make the low 32-bits of the64-bit hash value match the 32-bit hash value when the seed is 0.Robert Haas and Amul SulDiscussion:http://postgr.es/m/CA+Tgmoafx2yoJuhCQQOL5CocEi-w_uG4S2xT0EtgiJnPGcHW3g@mail.gmail.com

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33 files changed

+1555

-42

lines changed

doc/src/sgml
- xindex.sgml
src
- backend
  - access/hash
  - commands
    - opclasscmds.c
  - utils
    - adt
    - cache
      - lsyscache.c
      - typcache.c
- include
  - access
    - hash.h
  - catalog
  - fmgr.h
  - utils
    - jsonb.h
    - typcache.h
- test/regress
  - expected
    - alter_generic.out
    - hash_func.out
  - parallel_schedule
  - sql
    - hash_func.sql

33 files changed

+1555

-42

lines changed

`‎doc/src/sgml/xindex.sgml`

Lines changed: 11 additions & 2 deletions

Original file line number	Diff line number	Diff line change
`@@ -436,7 +436,8 @@`
`436`	`436`	`</table>`
`437`	`437`
`438`	`438`	`<para>`
`439`		`- Hash indexes require one support function, shown in <xref`
	`439`	`+ Hash indexes require one support function, and allow a second one to be`
	`440`	`+ supplied at the operator class author's option, as shown in <xref`
`440`	`441`	`linkend="xindex-hash-support-table">.`
`441`	`442`	`</para>`
`442`	`443`
`@@ -451,9 +452,17 @@`
`451`	`452`	`</thead>`
`452`	`453`	`<tbody>`
`453`	`454`	`<row>`
`454`		`- <entry>Compute the hash value for a key</entry>`
	`455`	`+ <entry>Compute the32-bithash value for a key</entry>`
`455`	`456`	`<entry>1</entry>`
`456`	`457`	`</row>`
	`458`	`+ <row>`
	`459`	`+ <entry>`
	`460`	`+ Compute the 64-bit hash value for a key given a 64-bit salt; if`
	`461`	`+ the salt is 0, the low 32 bits will match the value that would`
	`462`	`+ have been computed by function 1`
	`463`	`+ </entry>`
	`464`	`+ <entry>2</entry>`
	`465`	`+ </row>`
`457`	`466`	`</tbody>`
`458`	`467`	`</tgroup>`
`459`	`468`	`</table>`

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Commit81c5e46

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33 files changed

33 files changed

`‎doc/src/sgml/xindex.sgml`

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