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author | Bruce Momjian <bruce@momjian.us> | 2014-06-21 15:33:23 -0400 |
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committer | Bruce Momjian <bruce@momjian.us> | 2014-06-21 15:33:23 -0400 |
commit | 884dede37a056622510d6b2768abefb5ef981699 (patch) | |
tree | 2ec28e230a9d5096b57d8db6eaf28d325c530222 /doc/src | |
parent | a52f2a0b9cf6767d8c82bbc63725657bd84571d8 (diff) | |
download | postgresql-884dede37a056622510d6b2768abefb5ef981699.tar.gz postgresql-884dede37a056622510d6b2768abefb5ef981699.zip |
doc: adjust JSONB GIN index description
Backpatch through 9.4
Diffstat (limited to 'doc/src')
-rw-r--r-- | doc/src/sgml/json.sgml | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/doc/src/sgml/json.sgml b/doc/src/sgml/json.sgml index 66426189ca5..d55a08fb18a 100644 --- a/doc/src/sgml/json.sgml +++ b/doc/src/sgml/json.sgml @@ -460,11 +460,16 @@ SELECT jdoc->'guid', jdoc->'name' FROM api WHERE jdoc @> '{"tags": ["qu and a <literal>jsonb_path_ops</literal> GIN index is that the former creates independent index items for each key and value in the data, while the latter creates index items only for each value in the - data.<footnote><para>For this purpose, the term <quote>value</> - includes array elements, though JSON terminology sometimes considers - array elements distinct from values within objects.</para></footnote> - But in <literal>jsonb_path_ops</literal>, each index item is a hash - of both the value and the key(s) leading to it; for example to index + data. + <footnote> + <para> + For this purpose, the term <quote>value</> includes array elements, + though JSON terminology sometimes considers array elements distinct + from values within objects. + </para> + </footnote> + Basically, each <literal>jsonb_path_ops</literal> index item is + a hash of the value and the key(s) leading to it; for example to index <literal>{"foo": {"bar": "baz"}}</literal>, a single index item would be created incorporating all three of <literal>foo</>, <literal>bar</>, and <literal>baz</> into the hash value. Thus a containment query |