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  1. <?xml version="1.0" encoding="UTF-8" standalone="no"?>

  2. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>F.31. pg_trgm</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets V1.79.1" /><link rel="prev" href="pgstattuple.html" title="F.30. pgstattuple" /><link rel="next" href="pgvisibility.html" title="F.32. pg_visibility" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">F.31. pg_trgm</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="pgstattuple.html" title="F.30. pgstattuple">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="contrib.html" title="Appendix F. Additional Supplied Modules">Up</a></td><th width="60%" align="center">Appendix F. Additional Supplied Modules</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 12.4 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="pgvisibility.html" title="F.32. pg_visibility">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="PGTRGM"><div class="titlepage"><div><div><h2 class="title" style="clear: both">F.31. pg_trgm</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="sect2"><a href="pgtrgm.html#id-1.11.7.40.4">F.31.1. Trigram (or Trigraph) Concepts</a></span></dt><dt><span class="sect2"><a href="pgtrgm.html#id-1.11.7.40.5">F.31.2. Functions and Operators</a></span></dt><dt><span class="sect2"><a href="pgtrgm.html#id-1.11.7.40.6">F.31.3. GUC Parameters</a></span></dt><dt><span class="sect2"><a href="pgtrgm.html#id-1.11.7.40.7">F.31.4. Index Support</a></span></dt><dt><span class="sect2"><a href="pgtrgm.html#id-1.11.7.40.8">F.31.5. Text Search Integration</a></span></dt><dt><span class="sect2"><a href="pgtrgm.html#id-1.11.7.40.9">F.31.6. References</a></span></dt><dt><span class="sect2"><a href="pgtrgm.html#id-1.11.7.40.10">F.31.7. Authors</a></span></dt></dl></div><a id="id-1.11.7.40.2" class="indexterm"></a><p>

  3.   The <code class="filename">pg_trgm</code> module provides functions and operators

  4.   for determining the similarity of

  5.   alphanumeric text based on trigram matching, as

  6.   well as index operator classes that support fast searching for similar

  7.   strings.

  8.  </p><div class="sect2" id="id-1.11.7.40.4"><div class="titlepage"><div><div><h3 class="title">F.31.1. Trigram (or Trigraph) Concepts</h3></div></div></div><p>

  9.    A trigram is a group of three consecutive characters taken

  10.    from a string.  We can measure the similarity of two strings by

  11.    counting the number of trigrams they share.  This simple idea

  12.    turns out to be very effective for measuring the similarity of

  13.    words in many natural languages.

  14.   </p><div class="note"><h3 class="title">Note</h3><p>

  15.     <code class="filename">pg_trgm</code> ignores non-word characters

  16.     (non-alphanumerics) when extracting trigrams from a string.

  17.     Each word is considered to have two spaces

  18.     prefixed and one space suffixed when determining the set

  19.     of trigrams contained in the string.

  20.     For example, the set of trigrams in the string

  21.     <span class="quote">“<span class="quote"><code class="literal">cat</code></span>”</span> is

  22.     <span class="quote">“<span class="quote"><code class="literal">  c</code></span>”</span>,

  23.     <span class="quote">“<span class="quote"><code class="literal"> ca</code></span>”</span>,

  24.     <span class="quote">“<span class="quote"><code class="literal">cat</code></span>”</span>, and

  25.     <span class="quote">“<span class="quote"><code class="literal">at </code></span>”</span>.

  26.     The set of trigrams in the string

  27.     <span class="quote">“<span class="quote"><code class="literal">foo|bar</code></span>”</span> is

  28.     <span class="quote">“<span class="quote"><code class="literal">  f</code></span>”</span>,

  29.     <span class="quote">“<span class="quote"><code class="literal"> fo</code></span>”</span>,

  30.     <span class="quote">“<span class="quote"><code class="literal">foo</code></span>”</span>,

  31.     <span class="quote">“<span class="quote"><code class="literal">oo </code></span>”</span>,

  32.     <span class="quote">“<span class="quote"><code class="literal">  b</code></span>”</span>,

  33.     <span class="quote">“<span class="quote"><code class="literal"> ba</code></span>”</span>,

  34.     <span class="quote">“<span class="quote"><code class="literal">bar</code></span>”</span>, and

  35.     <span class="quote">“<span class="quote"><code class="literal">ar </code></span>”</span>.

  36.    </p></div></div><div class="sect2" id="id-1.11.7.40.5"><div class="titlepage"><div><div><h3 class="title">F.31.2. Functions and Operators</h3></div></div></div><p>

  37.    The functions provided by the <code class="filename">pg_trgm</code> module

  38.    are shown in <a class="xref" href="pgtrgm.html#PGTRGM-FUNC-TABLE" title="Table F.24. pg_trgm Functions">Table F.24</a>, the operators

  39.    in <a class="xref" href="pgtrgm.html#PGTRGM-OP-TABLE" title="Table F.25. pg_trgm Operators">Table F.25</a>.

  40.   </p><div class="table" id="PGTRGM-FUNC-TABLE"><p class="title"><strong>Table F.24. <code class="filename">pg_trgm</code> Functions</strong></p><div class="table-contents"><table class="table" summary="pg_trgm Functions" border="1"><colgroup><col /><col /><col /></colgroup><thead><tr><th>Function</th><th>Returns</th><th>Description</th></tr></thead><tbody><tr><td><code class="function">similarity(text, text)</code><a id="id-1.11.7.40.5.3.2.2.1.1.2" class="indexterm"></a></td><td><code class="type">real</code></td><td>

  41.        Returns a number that indicates how similar the two arguments are.

  42.        The range of the result is zero (indicating that the two strings are

  43.        completely dissimilar) to one (indicating that the two strings are

  44.        identical).

  45.       </td></tr><tr><td><code class="function">show_trgm(text)</code><a id="id-1.11.7.40.5.3.2.2.2.1.2" class="indexterm"></a></td><td><code class="type">text[]</code></td><td>

  46.        Returns an array of all the trigrams in the given string.

  47.        (In practice this is seldom useful except for debugging.)

  48.       </td></tr><tr><td>

  49.        <code class="function">word_similarity(text, text)</code>

  50.        <a id="id-1.11.7.40.5.3.2.2.3.1.2" class="indexterm"></a>

  51.       </td><td><code class="type">real</code></td><td>

  52.        Returns a number that indicates the greatest similarity between

  53.        the set of trigrams in the first string and any continuous extent

  54.        of an ordered set of trigrams in the second string.  For details, see

  55.        the explanation below.

  56.       </td></tr><tr><td>

  57.        <code class="function">strict_word_similarity(text, text)</code>

  58.        <a id="id-1.11.7.40.5.3.2.2.4.1.2" class="indexterm"></a>

  59.       </td><td><code class="type">real</code></td><td>

  60.        Same as <code class="function">word_similarity(text, text)</code>, but forces

  61.        extent boundaries to match word boundaries.  Since we don't have

  62.        cross-word trigrams, this function actually returns greatest similarity

  63.        between first string and any continuous extent of words of the second

  64.        string.

  65.       </td></tr><tr><td><code class="function">show_limit()</code><a id="id-1.11.7.40.5.3.2.2.5.1.2" class="indexterm"></a></td><td><code class="type">real</code></td><td>

  66.        Returns the current similarity threshold used by the <code class="literal">%</code>

  67.        operator.  This sets the minimum similarity between

  68.        two words for them to be considered similar enough to

  69.        be misspellings of each other, for example

  70.        (<span class="emphasis"><em>deprecated</em></span>).

  71.       </td></tr><tr><td><code class="function">set_limit(real)</code><a id="id-1.11.7.40.5.3.2.2.6.1.2" class="indexterm"></a></td><td><code class="type">real</code></td><td>

  72.        Sets the current similarity threshold that is used by the <code class="literal">%</code>

  73.        operator.  The threshold must be between 0 and 1 (default is 0.3).

  74.        Returns the same value passed in (<span class="emphasis"><em>deprecated</em></span>).

  75.       </td></tr></tbody></table></div></div><br class="table-break" /><p>

  76.    Consider the following example:

  77. 

  78. </p><pre class="programlisting">

  79. # SELECT word_similarity('word', 'two words');

  80.  word_similarity

  81. -----------------

  82.              0.8

  83. (1 row)

  84. </pre><p>

  85. 

  86.    In the first string, the set of trigrams is

  87.    <code class="literal">{"  w"," wo","wor","ord","rd "}</code>.

  88.    In the second string, the ordered set of trigrams is

  89.    <code class="literal">{"  t"," tw","two","wo ","  w"," wo","wor","ord","rds","ds "}</code>.

  90.    The most similar extent of an ordered set of trigrams in the second string

  91.    is <code class="literal">{"  w"," wo","wor","ord"}</code>, and the similarity is

  92.    <code class="literal">0.8</code>.

  93.   </p><p>

  94.    This function returns a value that can be approximately understood as the

  95.    greatest similarity between the first string and any substring of the second

  96.    string.  However, this function does not add padding to the boundaries of

  97.    the extent.  Thus, the number of additional characters present in the

  98.    second string is not considered, except for the mismatched word boundaries.

  99.   </p><p>

  100.    At the same time, <code class="function">strict_word_similarity(text, text)</code>

  101.    selects an extent of words in the second string.  In the example above,

  102.    <code class="function">strict_word_similarity(text, text)</code> would select the

  103.    extent of a single word <code class="literal">'words'</code>, whose set of trigrams is

  104.    <code class="literal">{"  w"," wo","wor","ord","rds","ds "}</code>.

  105. 

  106. </p><pre class="programlisting">

  107. # SELECT strict_word_similarity('word', 'two words'), similarity('word', 'words');

  108.  strict_word_similarity | similarity

  109. ------------------------+------------

  110.                0.571429 |   0.571429

  111. (1 row)

  112. </pre><p>

  113.   </p><p>

  114.    Thus, the <code class="function">strict_word_similarity(text, text)</code> function

  115.    is useful for finding the similarity to whole words, while

  116.    <code class="function">word_similarity(text, text)</code> is more suitable for

  117.    finding the similarity for parts of words.

  118.   </p><div class="table" id="PGTRGM-OP-TABLE"><p class="title"><strong>Table F.25. <code class="filename">pg_trgm</code> Operators</strong></p><div class="table-contents"><table class="table" summary="pg_trgm Operators" border="1"><colgroup><col /><col /><col /></colgroup><thead><tr><th>Operator</th><th>Returns</th><th>Description</th></tr></thead><tbody><tr><td><code class="type">text</code> <code class="literal">%</code> <code class="type">text</code></td><td><code class="type">boolean</code></td><td>

  119.        Returns <code class="literal">true</code> if its arguments have a similarity that is

  120.        greater than the current similarity threshold set by

  121.        <code class="varname">pg_trgm.similarity_threshold</code>.

  122.       </td></tr><tr><td><code class="type">text</code> <code class="literal">&lt;%</code> <code class="type">text</code></td><td><code class="type">boolean</code></td><td>

  123.        Returns <code class="literal">true</code> if the similarity between the trigram

  124.        set in the first argument and a continuous extent of an ordered trigram

  125.        set in the second argument is greater than the current word similarity

  126.        threshold set by <code class="varname">pg_trgm.word_similarity_threshold</code>

  127.        parameter.

  128.       </td></tr><tr><td><code class="type">text</code> <code class="literal">%&gt;</code> <code class="type">text</code></td><td><code class="type">boolean</code></td><td>

  129.        Commutator of the <code class="literal">&lt;%</code> operator.

  130.       </td></tr><tr><td><code class="type">text</code> <code class="literal">&lt;&lt;%</code> <code class="type">text</code></td><td><code class="type">boolean</code></td><td>

  131.        Returns <code class="literal">true</code> if its second argument has a continuous

  132.        extent of an ordered trigram set that matches word boundaries,

  133.        and its similarity to the trigram set of the first argument is greater

  134.        than the current strict word similarity threshold set by the

  135.        <code class="varname">pg_trgm.strict_word_similarity_threshold</code> parameter.

  136.       </td></tr><tr><td><code class="type">text</code> <code class="literal">%&gt;&gt;</code> <code class="type">text</code></td><td><code class="type">boolean</code></td><td>

  137.        Commutator of the <code class="literal">&lt;&lt;%</code> operator.

  138.       </td></tr><tr><td><code class="type">text</code> <code class="literal">&lt;-&gt;</code> <code class="type">text</code></td><td><code class="type">real</code></td><td>

  139.        Returns the <span class="quote">“<span class="quote">distance</span>”</span> between the arguments, that is

  140.        one minus the <code class="function">similarity()</code> value.

  141.       </td></tr><tr><td>

  142.        <code class="type">text</code> <code class="literal">&lt;&lt;-&gt;</code> <code class="type">text</code>

  143.       </td><td><code class="type">real</code></td><td>

  144.        Returns the <span class="quote">“<span class="quote">distance</span>”</span> between the arguments, that is

  145.        one minus the <code class="function">word_similarity()</code> value.

  146.       </td></tr><tr><td>

  147.        <code class="type">text</code> <code class="literal">&lt;-&gt;&gt;</code> <code class="type">text</code>

  148.       </td><td><code class="type">real</code></td><td>

  149.        Commutator of the <code class="literal">&lt;&lt;-&gt;</code> operator.

  150.       </td></tr><tr><td>

  151.        <code class="type">text</code> <code class="literal">&lt;&lt;&lt;-&gt;</code> <code class="type">text</code>

  152.       </td><td><code class="type">real</code></td><td>

  153.        Returns the <span class="quote">“<span class="quote">distance</span>”</span> between the arguments, that is

  154.        one minus the <code class="function">strict_word_similarity()</code> value.

  155.       </td></tr><tr><td>

  156.        <code class="type">text</code> <code class="literal">&lt;-&gt;&gt;&gt;</code> <code class="type">text</code>

  157.       </td><td><code class="type">real</code></td><td>

  158.        Commutator of the <code class="literal">&lt;&lt;&lt;-&gt;</code> operator.

  159.       </td></tr></tbody></table></div></div><br class="table-break" /></div><div class="sect2" id="id-1.11.7.40.6"><div class="titlepage"><div><div><h3 class="title">F.31.3. GUC Parameters</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt id="GUC-PGTRGM-SIMILARITY-THRESHOLD"><span class="term">

  160.      <code class="varname">pg_trgm.similarity_threshold</code> (<code class="type">real</code>)

  161.      <a id="id-1.11.7.40.6.2.1.1.3" class="indexterm"></a>

  162.     </span></dt><dd><p>

  163.       Sets the current similarity threshold that is used by the <code class="literal">%</code>

  164.       operator.  The threshold must be between 0 and 1 (default is 0.3).

  165.      </p></dd><dt id="GUC-PGTRGM-WORD-SIMILARITY-THRESHOLD"><span class="term">

  166.      <code class="varname">pg_trgm.word_similarity_threshold</code> (<code class="type">real</code>)

  167.      <a id="id-1.11.7.40.6.2.2.1.3" class="indexterm"></a>

  168.     </span></dt><dd><p>

  169.       Sets the current word similarity threshold that is used by the

  170.       <code class="literal">&lt;%</code> and <code class="literal">%&gt;</code> operators.  The threshold

  171.       must be between 0 and 1 (default is 0.6).

  172.      </p></dd><dt id="GUC-PGTRGM-STRICT-WORD-SIMILARITY-THRESHOLD"><span class="term">

  173.      <code class="varname">pg_trgm.strict_word_similarity_threshold</code> (<code class="type">real</code>)

  174.      <a id="id-1.11.7.40.6.2.3.1.3" class="indexterm"></a>

  175.     </span></dt><dd><p>

  176.       Sets the current strict word similarity threshold that is used by the

  177.       <code class="literal">&lt;&lt;%</code> and <code class="literal">%&gt;&gt;</code> operators.  The threshold

  178.       must be between 0 and 1 (default is 0.5).

  179.      </p></dd></dl></div></div><div class="sect2" id="id-1.11.7.40.7"><div class="titlepage"><div><div><h3 class="title">F.31.4. Index Support</h3></div></div></div><p>

  180.    The <code class="filename">pg_trgm</code> module provides GiST and GIN index

  181.    operator classes that allow you to create an index over a text column for

  182.    the purpose of very fast similarity searches.  These index types support

  183.    the above-described similarity operators, and additionally support

  184.    trigram-based index searches for <code class="literal">LIKE</code>, <code class="literal">ILIKE</code>,

  185.    <code class="literal">~</code> and <code class="literal">~*</code> queries.  (These indexes do not

  186.    support equality nor simple comparison operators, so you may need a

  187.    regular B-tree index too.)

  188.   </p><p>

  189.    Example:

  190. 

  191. </p><pre class="programlisting">

  192. CREATE TABLE test_trgm (t text);

  193. CREATE INDEX trgm_idx ON test_trgm USING GIST (t gist_trgm_ops);

  194. </pre><p>

  195. or

  196. </p><pre class="programlisting">

  197. CREATE INDEX trgm_idx ON test_trgm USING GIN (t gin_trgm_ops);

  198. </pre><p>

  199.   </p><p>

  200.    At this point, you will have an index on the <code class="structfield">t</code> column that

  201.    you can use for similarity searching.  A typical query is

  202. </p><pre class="programlisting">

  203. SELECT t, similarity(t, '<em class="replaceable"><code>word</code></em>') AS sml

  204.   FROM test_trgm

  205.   WHERE t % '<em class="replaceable"><code>word</code></em>'

  206.   ORDER BY sml DESC, t;

  207. </pre><p>

  208.    This will return all values in the text column that are sufficiently

  209.    similar to <em class="replaceable"><code>word</code></em>, sorted from best match to worst.  The

  210.    index will be used to make this a fast operation even over very large data

  211.    sets.

  212.   </p><p>

  213.    A variant of the above query is

  214. </p><pre class="programlisting">

  215. SELECT t, t &lt;-&gt; '<em class="replaceable"><code>word</code></em>' AS dist

  216.   FROM test_trgm

  217.   ORDER BY dist LIMIT 10;

  218. </pre><p>

  219.    This can be implemented quite efficiently by GiST indexes, but not

  220.    by GIN indexes.  It will usually beat the first formulation when only

  221.    a small number of the closest matches is wanted.

  222.   </p><p>

  223.    Also you can use an index on the <code class="structfield">t</code> column for word

  224.    similarity or strict word similarity.  Typical queries are:

  225. </p><pre class="programlisting">

  226. SELECT t, word_similarity('<em class="replaceable"><code>word</code></em>', t) AS sml

  227.   FROM test_trgm

  228.   WHERE '<em class="replaceable"><code>word</code></em>' &lt;% t

  229.   ORDER BY sml DESC, t;

  230. </pre><p>

  231.    and

  232. </p><pre class="programlisting">

  233. SELECT t, strict_word_similarity('<em class="replaceable"><code>word</code></em>', t) AS sml

  234.   FROM test_trgm

  235.   WHERE '<em class="replaceable"><code>word</code></em>' &lt;&lt;% t

  236.   ORDER BY sml DESC, t;

  237. </pre><p>

  238.    This will return all values in the text column for which there is a

  239.    continuous extent in the corresponding ordered trigram set that is

  240.    sufficiently similar to the trigram set of <em class="replaceable"><code>word</code></em>,

  241.    sorted from best match to worst.  The index will be used to make this

  242.    a fast operation even over very large data sets.

  243.   </p><p>

  244.    Possible variants of the above queries are:

  245. </p><pre class="programlisting">

  246. SELECT t, '<em class="replaceable"><code>word</code></em>' &lt;&lt;-&gt; t AS dist

  247.   FROM test_trgm

  248.   ORDER BY dist LIMIT 10;

  249. </pre><p>

  250.    and

  251. </p><pre class="programlisting">

  252. SELECT t, '<em class="replaceable"><code>word</code></em>' &lt;&lt;&lt;-&gt; t AS dist

  253.   FROM test_trgm

  254.   ORDER BY dist LIMIT 10;

  255. </pre><p>

  256.    This can be implemented quite efficiently by GiST indexes, but not

  257.    by GIN indexes.

  258.   </p><p>

  259.    Beginning in <span class="productname">PostgreSQL</span> 9.1, these index types also support

  260.    index searches for <code class="literal">LIKE</code> and <code class="literal">ILIKE</code>, for example

  261. </p><pre class="programlisting">

  262. SELECT * FROM test_trgm WHERE t LIKE '%foo%bar';

  263. </pre><p>

  264.    The index search works by extracting trigrams from the search string

  265.    and then looking these up in the index.  The more trigrams in the search

  266.    string, the more effective the index search is.  Unlike B-tree based

  267.    searches, the search string need not be left-anchored.

  268.   </p><p>

  269.    Beginning in <span class="productname">PostgreSQL</span> 9.3, these index types also support

  270.    index searches for regular-expression matches

  271.    (<code class="literal">~</code> and <code class="literal">~*</code> operators), for example

  272. </p><pre class="programlisting">

  273. SELECT * FROM test_trgm WHERE t ~ '(foo|bar)';

  274. </pre><p>

  275.    The index search works by extracting trigrams from the regular expression

  276.    and then looking these up in the index.  The more trigrams that can be

  277.    extracted from the regular expression, the more effective the index search

  278.    is.  Unlike B-tree based searches, the search string need not be

  279.    left-anchored.

  280.   </p><p>

  281.    For both <code class="literal">LIKE</code> and regular-expression searches, keep in mind

  282.    that a pattern with no extractable trigrams will degenerate to a full-index

  283.    scan.

  284.   </p><p>

  285.    The choice between GiST and GIN indexing depends on the relative

  286.    performance characteristics of GiST and GIN, which are discussed elsewhere.

  287.   </p></div><div class="sect2" id="id-1.11.7.40.8"><div class="titlepage"><div><div><h3 class="title">F.31.5. Text Search Integration</h3></div></div></div><p>

  288.    Trigram matching is a very useful tool when used in conjunction

  289.    with a full text index.  In particular it can help to recognize

  290.    misspelled input words that will not be matched directly by the

  291.    full text search mechanism.

  292.   </p><p>

  293.    The first step is to generate an auxiliary table containing all

  294.    the unique words in the documents:

  295. 

  296. </p><pre class="programlisting">

  297. CREATE TABLE words AS SELECT word FROM

  298.         ts_stat('SELECT to_tsvector(''simple'', bodytext) FROM documents');

  299. </pre><p>

  300. 

  301.    where <code class="structname">documents</code> is a table that has a text field

  302.    <code class="structfield">bodytext</code> that we wish to search.  The reason for using

  303.    the <code class="literal">simple</code> configuration with the <code class="function">to_tsvector</code>

  304.    function, instead of using a language-specific configuration,

  305.    is that we want a list of the original (unstemmed) words.

  306.   </p><p>

  307.    Next, create a trigram index on the word column:

  308. 

  309. </p><pre class="programlisting">

  310. CREATE INDEX words_idx ON words USING GIN (word gin_trgm_ops);

  311. </pre><p>

  312. 

  313.    Now, a <code class="command">SELECT</code> query similar to the previous example can

  314.    be used to suggest spellings for misspelled words in user search terms.

  315.    A useful extra test is to require that the selected words are also of

  316.    similar length to the misspelled word.

  317.   </p><div class="note"><h3 class="title">Note</h3><p>

  318.     Since the <code class="structname">words</code> table has been generated as a separate,

  319.     static table, it will need to be periodically regenerated so that

  320.     it remains reasonably up-to-date with the document collection.

  321.     Keeping it exactly current is usually unnecessary.

  322.    </p></div></div><div class="sect2" id="id-1.11.7.40.9"><div class="titlepage"><div><div><h3 class="title">F.31.6. References</h3></div></div></div><p>

  323.    GiST Development Site

  324.    <a class="ulink" href="http://www.sai.msu.su/~megera/postgres/gist/" target="_top">http://www.sai.msu.su/~megera/postgres/gist/</a>

  325.   </p><p>

  326.    Tsearch2 Development Site

  327.    <a class="ulink" href="http://www.sai.msu.su/~megera/postgres/gist/tsearch/V2/" target="_top">http://www.sai.msu.su/~megera/postgres/gist/tsearch/V2/</a>

  328.   </p></div><div class="sect2" id="id-1.11.7.40.10"><div class="titlepage"><div><div><h3 class="title">F.31.7. Authors</h3></div></div></div><p>

  329.    Oleg Bartunov <code class="email">&lt;<a class="email" href="mailto:oleg@sai.msu.su">oleg@sai.msu.su</a>&gt;</code>, Moscow, Moscow University, Russia

  330.   </p><p>

  331.    Teodor Sigaev <code class="email">&lt;<a class="email" href="mailto:teodor@sigaev.ru">teodor@sigaev.ru</a>&gt;</code>, Moscow, Delta-Soft Ltd.,Russia

  332.   </p><p>

  333.    Alexander Korotkov <code class="email">&lt;<a class="email" href="mailto:a.korotkov@postgrespro.ru">a.korotkov@postgrespro.ru</a>&gt;</code>, Moscow, Postgres Professional, Russia

  334.   </p><p>

  335.    Documentation: Christopher Kings-Lynne

  336.   </p><p>

  337.    This module is sponsored by Delta-Soft Ltd., Moscow, Russia.

  338.   </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="pgstattuple.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="contrib.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="pgvisibility.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">F.30. pgstattuple </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> F.32. pg_visibility</td></tr></table></div></body></html>
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