From d3f077b813efa90b25a162bf8d227f3e4218c248 Mon Sep 17 00:00:00 2001 From: Justin Pryzby Date: Mon, 30 Mar 2020 20:55:06 -0500 Subject: [PATCH v1] Doc review: Implement operator class parameters commit 911e70207703799605f5a0e8aad9f06cff067c63 Author: Alexander Korotkov --- doc/src/sgml/hstore.sgml | 12 ++++++------ doc/src/sgml/intarray.sgml | 27 ++++++++++++++------------- doc/src/sgml/ltree.sgml | 20 ++++++++++---------- doc/src/sgml/pgtrgm.sgml | 12 ++++++------ doc/src/sgml/textsearch.sgml | 12 ++++++------ 5 files changed, 42 insertions(+), 41 deletions(-) diff --git a/doc/src/sgml/hstore.sgml b/doc/src/sgml/hstore.sgml index f1f2b08cd7..b2e04d0815 100644 --- a/doc/src/sgml/hstore.sgml +++ b/doc/src/sgml/hstore.sgml @@ -468,13 +468,13 @@ CREATE INDEX hidx ON testhstore USING GIN (h); - gist_hstore_ops GiST opclass approximates set of - key/value pairs as a bitmap signature. Optional integer parameter - siglen of gist_hstore_ops determines - signature length in bytes. Default signature length is 16 bytes. + gist_hstore_ops GiST opclass approximates a set of + key/value pairs as a bitmap signature. Its optional integer parameter + siglen determines the + signature length in bytes. The default length is 16 bytes. Valid values of signature length are between 1 and 2024 bytes. Longer - signatures leads to more precise search (scan less fraction of index, scan - less heap pages), but larger index. + signatures lead to a more precise search (scanning a smaller fraction of the index and + fewer heap pages), at the cost of a larger index. diff --git a/doc/src/sgml/intarray.sgml b/doc/src/sgml/intarray.sgml index 72b4b23c15..7956a746a6 100644 --- a/doc/src/sgml/intarray.sgml +++ b/doc/src/sgml/intarray.sgml @@ -265,7 +265,7 @@ - Two parametrized GiST index operator classes are provided: + Two parameterized GiST index operator classes are provided: gist__int_ops (used by default) is suitable for small- to medium-size data sets, while gist__intbig_ops uses a larger signature and is more @@ -276,22 +276,23 @@ - gist__int_ops approximates integer set as an array of - integer ranges. Optional integer parameter numranges of - gist__int_ops determines maximum number of ranges in - one index key. Default value of numranges is 100. + gist__int_ops approximates an integer set as an array of + integer ranges. Its optional integer parameter numranges + determines the maximum number of ranges in + one index key. The default value of numranges is 100. Valid values are between 1 and 253. Using larger arrays as GiST index - keys leads to more precise search (scan less fraction of index, scan less - heap pages), but larger index. + keys leads to a more precise search (scaning a smaller fraction of the index and + fewer heap pages), at the cost of a larger index. - gist__intbig_ops approximates integer set as a bitmap - signature. Optional integer parameter siglen of - gist__intbig_ops determines signature length in bytes. - Default signature length is 16 bytes. Valid values of signature length - are between 1 and 2024 bytes. Longer signatures leads to more precise - search (scan less fraction of index, scan less heap pages), but larger index. + gist__intbig_ops approximates an integer set as a bitmap + signature XXX. Its optional integer parameter siglen + determines the signature length in bytes. + The default signature length is 16 bytes. Valid values of signature length + are between 1 and 2024 bytes. Longer signatures lead to a more precise + search (scanning a smaller fraction of the index and fewer heap pages), at + the cost of a larger index. diff --git a/doc/src/sgml/ltree.sgml b/doc/src/sgml/ltree.sgml index ae4b33ec85..4971b71524 100644 --- a/doc/src/sgml/ltree.sgml +++ b/doc/src/sgml/ltree.sgml @@ -506,16 +506,16 @@ Europe & Russia*@ & !Transportation @, ~, ? - gist_ltree_ops GiST opclass approximates set of - path labels as a bitmap signature. Optional integer parameter - siglen of gist_ltree_ops determines - signature length in bytes. Default signature length is 8 bytes. + gist_ltree_ops GiST opclass approximates a set of + path labels as a bitmap signature. Its optional integer parameter + siglen determines the + signature length in bytes. The default signature length is 8 bytes. Valid values of signature length are between 1 and 2024 bytes. Longer - signatures leads to more precise search (scan less fraction of index, scan - less heap pages), but larger index. + signatures lead to a more precise search (scanning a smaller fraction of the index and + fewer heap pages), at the cost of a larger index. - Example of creating such an index with a default signature length of 8 bytes: + Example of creating such an index with the default signature length of 8 bytes: CREATE INDEX path_gist_idx ON test USING GIST (path); @@ -535,13 +535,13 @@ CREATE INDEX path_gist_idx ON test USING GIST (path gist_ltree_ops(siglen=100)); @, ~, ? - gist__ltree_ops GiST opclass works similar to + gist__ltree_ops GiST opclass works similarly to gist_ltree_ops and also takes signature length as - a parameter. Default value of siglen in + a parameter. The default value of siglen in gist__ltree_ops is 28 bytes. - Example of creating such an index with a default signature length of 28 bytes: + Example of creating such an index with the default signature length of 28 bytes: CREATE INDEX path_gist_idx ON test USING GIST (array_path); diff --git a/doc/src/sgml/pgtrgm.sgml b/doc/src/sgml/pgtrgm.sgml index dde02634ae..97b3d13a88 100644 --- a/doc/src/sgml/pgtrgm.sgml +++ b/doc/src/sgml/pgtrgm.sgml @@ -391,13 +391,13 @@ CREATE INDEX trgm_idx ON test_trgm USING GIN (t gin_trgm_ops); - gist_trgm_ops GiST opclass approximates set of - trigrams as a bitmap signature. Optional integer parameter - siglen of gist_trgm_ops determines - signature length in bytes. Default signature length is 12 bytes. + gist_trgm_ops GiST opclass approximates a set of + trigrams as a bitmap signature. Its optional integer parameter + siglen determines the + signature length in bytes. The default length is 12 bytes. Valid values of signature length are between 1 and 2024 bytes. Longer - signatures leads to more precise search (scan less fraction of index, scan - less heap pages), but larger index. + signatures lead to a more precise search (scanning a smaller fraction of the index and + fewer heap pages), at the cost of a larger index. diff --git a/doc/src/sgml/textsearch.sgml b/doc/src/sgml/textsearch.sgml index 2217fcd6c2..0dc427289d 100644 --- a/doc/src/sgml/textsearch.sgml +++ b/doc/src/sgml/textsearch.sgml @@ -3670,17 +3670,17 @@ SELECT plainto_tsquery('supernovae stars'); to check the actual table row to eliminate such false matches. (PostgreSQL does this automatically when needed.) GiST indexes are lossy because each document is represented in the - index by a fixed-length signature. Signature length in bytes is determined + index by a fixed-length signature. The signature length in bytes is determined by the value of the optional integer parameter siglen. - Default signature length (when siglen is not specied) is - 124 bytes, maximal length is 2024 bytes. The signature is generated by hashing + The default signature length (when siglen is not specified) is + 124 bytes, the maximum signature length is 2024 bytes. The signature is generated by hashing each word into a single bit in an n-bit string, with all these bits OR-ed together to produce an n-bit document signature. When two words hash to the same bit position there will be a false match. If all words in the query have matches (real or false) then the table row must be - retrieved to see if the match is correct. Longer signatures leads to more - precise search (scan less fraction of index, scan less heap pages), but - larger index. + retrieved to see if the match is correct. Longer signatures lead to a more + precise search (scanning a smaller fraction of the index and fewer heap + pages), at the cost of a larger index. -- 2.17.0