1335 lines
52 KiB
Plaintext
1335 lines
52 KiB
Plaintext
<!-- doc/src/sgml/brin.sgml -->
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<chapter id="brin">
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<title>BRIN Indexes</title>
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<indexterm>
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<primary>index</primary>
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<secondary>BRIN</secondary>
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</indexterm>
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<sect1 id="brin-intro">
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<title>Introduction</title>
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<para>
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<acronym>BRIN</acronym> stands for Block Range Index.
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<acronym>BRIN</acronym> is designed for handling very large tables
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in which certain columns have some natural correlation with their
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physical location within the table.
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</para>
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<para>
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<acronym>BRIN</acronym> works in terms of <firstterm>block ranges</firstterm>
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(or <quote>page ranges</quote>).
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A block range is a group of pages that are physically
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adjacent in the table; for each block range, some summary info is stored
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by the index.
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For example, a table storing a store's sale orders might have
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a date column on which each order was placed, and most of the time
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the entries for earlier orders will appear earlier in the table as well;
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a table storing a ZIP code column might have all codes for a city
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grouped together naturally.
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</para>
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<para>
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<acronym>BRIN</acronym> indexes can satisfy queries via regular bitmap
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index scans, and will return all tuples in all pages within each range if
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the summary info stored by the index is <firstterm>consistent</firstterm> with the
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query conditions.
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The query executor is in charge of rechecking these tuples and discarding
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those that do not match the query conditions — in other words, these
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indexes are lossy.
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Because a <acronym>BRIN</acronym> index is very small, scanning the index
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adds little overhead compared to a sequential scan, but may avoid scanning
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large parts of the table that are known not to contain matching tuples.
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</para>
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<para>
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The specific data that a <acronym>BRIN</acronym> index will store,
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as well as the specific queries that the index will be able to satisfy,
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depend on the operator class selected for each column of the index.
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Data types having a linear sort order can have operator classes that
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store the minimum and maximum value within each block range, for instance;
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geometrical types might store the bounding box for all the objects
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in the block range.
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</para>
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<para>
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The size of the block range is determined at index creation time by
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the <literal>pages_per_range</literal> storage parameter. The number of index
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entries will be equal to the size of the relation in pages divided by
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the selected value for <literal>pages_per_range</literal>. Therefore, the smaller
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the number, the larger the index becomes (because of the need to
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store more index entries), but at the same time the summary data stored can
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be more precise and more data blocks can be skipped during an index scan.
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</para>
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<sect2 id="brin-operation">
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<title>Index Maintenance</title>
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<para>
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At the time of creation, all existing heap pages are scanned and a
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summary index tuple is created for each range, including the
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possibly-incomplete range at the end.
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As new pages are filled with data, page ranges that are already
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summarized will cause the summary information to be updated with data
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from the new tuples.
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When a new page is created that does not fall within the last
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summarized range, the range that the new page belongs to
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does not automatically acquire a summary tuple;
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those tuples remain unsummarized until a summarization run is
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invoked later, creating the initial summary for that range.
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</para>
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<para>
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There are several ways to trigger the initial summarization of a page range.
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If the table is vacuumed, either manually or by
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<link linkend="autovacuum">autovacuum</link>, all existing unsummarized
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page ranges are summarized.
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Also, if the index's
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<xref linkend="index-reloption-autosummarize"/> parameter is enabled,
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which it isn't by default,
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whenever autovacuum runs in that database, summarization will occur for all
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unsummarized page ranges that have been filled,
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regardless of whether the table itself is processed by autovacuum; see below.
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</para>
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<para>
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Lastly, the following functions can be used:
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<simplelist>
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<member>
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<function>brin_summarize_new_values(regclass)</function>
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which summarizes all unsummarized ranges;
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</member>
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<member>
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<function>brin_summarize_range(regclass, bigint)</function>
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which summarizes only the range containing the given page,
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if it is unsummarized.
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</member>
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</simplelist>
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</para>
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<para>
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When autosummarization is enabled, a request is sent to
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<literal>autovacuum</literal> to execute a targeted summarization
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for a block range when an insertion is detected for the first item
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of the first page of the next block range,
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to be fulfilled the next time an autovacuum
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worker finishes running in the
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same database. If the request queue is full, the request is not recorded
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and a message is sent to the server log:
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<screen>
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LOG: request for BRIN range summarization for index "brin_wi_idx" page 128 was not recorded
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</screen>
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When this happens, the range will remain unsummarized until the next
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regular vacuum run on the table, or one of the functions mentioned above
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are invoked.
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</para>
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<para>
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Conversely, a range can be de-summarized using the
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<function>brin_desummarize_range(regclass, bigint)</function> function,
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which is useful when the index tuple is no longer a very good
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representation because the existing values have changed.
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See <xref linkend="functions-admin-index"/> for details.
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</para>
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</sect2>
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</sect1>
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<sect1 id="brin-builtin-opclasses">
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<title>Built-in Operator Classes</title>
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<para>
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The core <productname>PostgreSQL</productname> distribution
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includes the <acronym>BRIN</acronym> operator classes shown in
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<xref linkend="brin-builtin-opclasses-table"/>.
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</para>
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<para>
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The <firstterm>minmax</firstterm>
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operator classes store the minimum and the maximum values appearing
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in the indexed column within the range. The <firstterm>inclusion</firstterm>
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operator classes store a value which includes the values in the indexed
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column within the range. The <firstterm>bloom</firstterm> operator
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classes build a Bloom filter for all values in the range. The
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<firstterm>minmax-multi</firstterm> operator classes store multiple
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minimum and maximum values, representing values appearing in the indexed
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column within the range.
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</para>
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<table id="brin-builtin-opclasses-table">
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<title>Built-in <acronym>BRIN</acronym> Operator Classes</title>
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<tgroup cols="2">
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<thead>
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<row>
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<entry>Name</entry>
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<entry>Indexable Operators</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry valign="middle" morerows="4"><literal>bit_minmax_ops</literal></entry>
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<entry><literal>= (bit,bit)</literal></entry>
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</row>
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<row><entry><literal>< (bit,bit)</literal></entry></row>
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<row><entry><literal>> (bit,bit)</literal></entry></row>
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<row><entry><literal><= (bit,bit)</literal></entry></row>
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<row><entry><literal>>= (bit,bit)</literal></entry></row>
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<row>
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<entry valign="middle" morerows="12"><literal>box_inclusion_ops</literal></entry>
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<entry><literal>@> (box,point)</literal></entry>
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</row>
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<row><entry><literal><< (box,box)</literal></entry></row>
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<row><entry><literal>&< (box,box)</literal></entry></row>
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<row><entry><literal>&> (box,box)</literal></entry></row>
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<row><entry><literal>>> (box,box)</literal></entry></row>
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<row><entry><literal><@ (box,box)</literal></entry></row>
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<row><entry><literal>@> (box,box)</literal></entry></row>
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<row><entry><literal>~= (box,box)</literal></entry></row>
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<row><entry><literal>&& (box,box)</literal></entry></row>
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<row><entry><literal><<| (box,box)</literal></entry></row>
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<row><entry><literal>&<| (box,box)</literal></entry></row>
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<row><entry><literal>|&> (box,box)</literal></entry></row>
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<row><entry><literal>|>> (box,box)</literal></entry></row>
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<row>
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<entry valign="middle"><literal>bpchar_bloom_ops</literal></entry>
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<entry><literal>= (character,character)</literal></entry>
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</row>
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<row>
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<entry valign="middle" morerows="4"><literal>bpchar_minmax_ops</literal></entry>
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<entry><literal>= (character,character)</literal></entry>
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</row>
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<row><entry><literal>< (character,character)</literal></entry></row>
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<row><entry><literal><= (character,character)</literal></entry></row>
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<row><entry><literal>> (character,character)</literal></entry></row>
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<row><entry><literal>>= (character,character)</literal></entry></row>
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<row>
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<entry valign="middle"><literal>bytea_bloom_ops</literal></entry>
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<entry><literal>= (bytea,bytea)</literal></entry>
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</row>
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<row>
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<entry valign="middle" morerows="4"><literal>bytea_minmax_ops</literal></entry>
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<entry><literal>= (bytea,bytea)</literal></entry>
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</row>
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<row><entry><literal>< (bytea,bytea)</literal></entry></row>
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<row><entry><literal><= (bytea,bytea)</literal></entry></row>
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<row><entry><literal>> (bytea,bytea)</literal></entry></row>
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<row><entry><literal>>= (bytea,bytea)</literal></entry></row>
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<row>
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<entry valign="middle"><literal>char_bloom_ops</literal></entry>
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<entry><literal>= ("char","char")</literal></entry>
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</row>
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<row>
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<entry valign="middle" morerows="4"><literal>char_minmax_ops</literal></entry>
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<entry><literal>= ("char","char")</literal></entry>
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</row>
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<row><entry><literal>< ("char","char")</literal></entry></row>
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<row><entry><literal><= ("char","char")</literal></entry></row>
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<row><entry><literal>> ("char","char")</literal></entry></row>
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<row><entry><literal>>= ("char","char")</literal></entry></row>
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<row>
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<entry valign="middle"><literal>date_bloom_ops</literal></entry>
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<entry><literal>= (date,date)</literal></entry>
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</row>
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<row>
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<entry valign="middle" morerows="4"><literal>date_minmax_ops</literal></entry>
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<entry><literal>= (date,date)</literal></entry>
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</row>
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<row><entry><literal>< (date,date)</literal></entry></row>
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<row><entry><literal><= (date,date)</literal></entry></row>
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<row><entry><literal>> (date,date)</literal></entry></row>
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<row><entry><literal>>= (date,date)</literal></entry></row>
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<row>
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<entry valign="middle" morerows="4"><literal>date_minmax_multi_ops</literal></entry>
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<entry><literal>= (date,date)</literal></entry>
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</row>
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<row><entry><literal>< (date,date)</literal></entry></row>
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<row><entry><literal><= (date,date)</literal></entry></row>
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<row><entry><literal>> (date,date)</literal></entry></row>
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<row><entry><literal>>= (date,date)</literal></entry></row>
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<row>
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<entry valign="middle"><literal>float4_bloom_ops</literal></entry>
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<entry><literal>= (float4,float4)</literal></entry>
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</row>
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<row>
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<entry valign="middle" morerows="4"><literal>float4_minmax_ops</literal></entry>
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<entry><literal>= (float4,float4)</literal></entry>
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</row>
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<row><entry><literal>< (float4,float4)</literal></entry></row>
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<row><entry><literal>> (float4,float4)</literal></entry></row>
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<row><entry><literal><= (float4,float4)</literal></entry></row>
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<row><entry><literal>>= (float4,float4)</literal></entry></row>
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<row>
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<entry valign="middle" morerows="4"><literal>float4_minmax_multi_ops</literal></entry>
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<entry><literal>= (float4,float4)</literal></entry>
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</row>
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<row><entry><literal>< (float4,float4)</literal></entry></row>
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<row><entry><literal>> (float4,float4)</literal></entry></row>
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<row><entry><literal><= (float4,float4)</literal></entry></row>
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<row><entry><literal>>= (float4,float4)</literal></entry></row>
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<row>
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<entry valign="middle"><literal>float8_bloom_ops</literal></entry>
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<entry><literal>= (float8,float8)</literal></entry>
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</row>
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<row>
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<entry valign="middle" morerows="4"><literal>float8_minmax_ops</literal></entry>
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<entry><literal>= (float8,float8)</literal></entry>
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</row>
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<row><entry><literal>< (float8,float8)</literal></entry></row>
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<row><entry><literal><= (float8,float8)</literal></entry></row>
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<row><entry><literal>> (float8,float8)</literal></entry></row>
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<row><entry><literal>>= (float8,float8)</literal></entry></row>
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<row>
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<entry valign="middle" morerows="4"><literal>float8_minmax_multi_ops</literal></entry>
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<entry><literal>= (float8,float8)</literal></entry>
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</row>
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<row><entry><literal>< (float8,float8)</literal></entry></row>
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<row><entry><literal><= (float8,float8)</literal></entry></row>
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<row><entry><literal>> (float8,float8)</literal></entry></row>
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<row><entry><literal>>= (float8,float8)</literal></entry></row>
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<row>
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<entry valign="middle" morerows="5"><literal>inet_inclusion_ops</literal></entry>
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<entry><literal><< (inet,inet)</literal></entry>
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</row>
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<row><entry><literal><<= (inet,inet)</literal></entry></row>
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<row><entry><literal>>> (inet,inet)</literal></entry></row>
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<row><entry><literal>>>= (inet,inet)</literal></entry></row>
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<row><entry><literal>= (inet,inet)</literal></entry></row>
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<row><entry><literal>&& (inet,inet)</literal></entry></row>
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<row>
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<entry valign="middle"><literal>inet_bloom_ops</literal></entry>
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<entry><literal>= (inet,inet)</literal></entry>
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</row>
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<row>
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<entry valign="middle" morerows="4"><literal>inet_minmax_ops</literal></entry>
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<entry><literal>= (inet,inet)</literal></entry>
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</row>
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<row><entry><literal>< (inet,inet)</literal></entry></row>
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<row><entry><literal><= (inet,inet)</literal></entry></row>
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<row><entry><literal>> (inet,inet)</literal></entry></row>
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<row><entry><literal>>= (inet,inet)</literal></entry></row>
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<row>
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<entry valign="middle" morerows="4"><literal>inet_minmax_multi_ops</literal></entry>
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<entry><literal>= (inet,inet)</literal></entry>
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</row>
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<row><entry><literal>< (inet,inet)</literal></entry></row>
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<row><entry><literal><= (inet,inet)</literal></entry></row>
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<row><entry><literal>> (inet,inet)</literal></entry></row>
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<row><entry><literal>>= (inet,inet)</literal></entry></row>
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<row>
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<entry valign="middle"><literal>int2_bloom_ops</literal></entry>
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<entry><literal>= (int2,int2)</literal></entry>
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</row>
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<row>
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<entry valign="middle" morerows="4"><literal>int2_minmax_ops</literal></entry>
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<entry><literal>= (int2,int2)</literal></entry>
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</row>
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<row><entry><literal>< (int2,int2)</literal></entry></row>
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<row><entry><literal>> (int2,int2)</literal></entry></row>
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<row><entry><literal><= (int2,int2)</literal></entry></row>
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<row><entry><literal>>= (int2,int2)</literal></entry></row>
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<row>
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<entry valign="middle" morerows="4"><literal>int2_minmax_multi_ops</literal></entry>
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<entry><literal>= (int2,int2)</literal></entry>
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</row>
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<row><entry><literal>< (int2,int2)</literal></entry></row>
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<row><entry><literal>> (int2,int2)</literal></entry></row>
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<row><entry><literal><= (int2,int2)</literal></entry></row>
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<row><entry><literal>>= (int2,int2)</literal></entry></row>
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<row>
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<entry valign="middle"><literal>int4_bloom_ops</literal></entry>
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<entry><literal>= (int4,int4)</literal></entry>
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</row>
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<row>
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<entry valign="middle" morerows="4"><literal>int4_minmax_ops</literal></entry>
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<entry><literal>= (int4,int4)</literal></entry>
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</row>
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<row><entry><literal>< (int4,int4)</literal></entry></row>
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<row><entry><literal>> (int4,int4)</literal></entry></row>
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<row><entry><literal><= (int4,int4)</literal></entry></row>
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<row><entry><literal>>= (int4,int4)</literal></entry></row>
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<row>
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<entry valign="middle" morerows="4"><literal>int4_minmax_multi_ops</literal></entry>
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<entry><literal>= (int4,int4)</literal></entry>
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</row>
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<row><entry><literal>< (int4,int4)</literal></entry></row>
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<row><entry><literal>> (int4,int4)</literal></entry></row>
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<row><entry><literal><= (int4,int4)</literal></entry></row>
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<row><entry><literal>>= (int4,int4)</literal></entry></row>
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<row>
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<entry valign="middle"><literal>int8_bloom_ops</literal></entry>
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<entry><literal>= (bigint,bigint)</literal></entry>
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</row>
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<row>
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<entry valign="middle" morerows="4"><literal>int8_minmax_ops</literal></entry>
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<entry><literal>= (bigint,bigint)</literal></entry>
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</row>
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<row><entry><literal>< (bigint,bigint)</literal></entry></row>
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<row><entry><literal>> (bigint,bigint)</literal></entry></row>
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<row><entry><literal><= (bigint,bigint)</literal></entry></row>
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<row><entry><literal>>= (bigint,bigint)</literal></entry></row>
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<row>
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<entry valign="middle" morerows="4"><literal>int8_minmax_multi_ops</literal></entry>
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<entry><literal>= (bigint,bigint)</literal></entry>
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</row>
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<row><entry><literal>< (bigint,bigint)</literal></entry></row>
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<row><entry><literal>> (bigint,bigint)</literal></entry></row>
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<row><entry><literal><= (bigint,bigint)</literal></entry></row>
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<row><entry><literal>>= (bigint,bigint)</literal></entry></row>
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<row>
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<entry valign="middle"><literal>interval_bloom_ops</literal></entry>
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<entry><literal>= (interval,interval)</literal></entry>
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</row>
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<row>
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<entry valign="middle" morerows="4"><literal>interval_minmax_ops</literal></entry>
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<entry><literal>= (interval,interval)</literal></entry>
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</row>
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<row><entry><literal>< (interval,interval)</literal></entry></row>
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<row><entry><literal><= (interval,interval)</literal></entry></row>
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<row><entry><literal>> (interval,interval)</literal></entry></row>
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<row><entry><literal>>= (interval,interval)</literal></entry></row>
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<row>
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<entry valign="middle" morerows="4"><literal>interval_minmax_multi_ops</literal></entry>
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<entry><literal>= (interval,interval)</literal></entry>
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</row>
|
|
<row><entry><literal>< (interval,interval)</literal></entry></row>
|
|
<row><entry><literal><= (interval,interval)</literal></entry></row>
|
|
<row><entry><literal>> (interval,interval)</literal></entry></row>
|
|
<row><entry><literal>>= (interval,interval)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle"><literal>macaddr_bloom_ops</literal></entry>
|
|
<entry><literal>= (macaddr,macaddr)</literal></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>macaddr_minmax_ops</literal></entry>
|
|
<entry><literal>= (macaddr,macaddr)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (macaddr,macaddr)</literal></entry></row>
|
|
<row><entry><literal><= (macaddr,macaddr)</literal></entry></row>
|
|
<row><entry><literal>> (macaddr,macaddr)</literal></entry></row>
|
|
<row><entry><literal>>= (macaddr,macaddr)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>macaddr_minmax_multi_ops</literal></entry>
|
|
<entry><literal>= (macaddr,macaddr)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (macaddr,macaddr)</literal></entry></row>
|
|
<row><entry><literal><= (macaddr,macaddr)</literal></entry></row>
|
|
<row><entry><literal>> (macaddr,macaddr)</literal></entry></row>
|
|
<row><entry><literal>>= (macaddr,macaddr)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle"><literal>macaddr8_bloom_ops</literal></entry>
|
|
<entry><literal>= (macaddr8,macaddr8)</literal></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>macaddr8_minmax_ops</literal></entry>
|
|
<entry><literal>= (macaddr8,macaddr8)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (macaddr8,macaddr8)</literal></entry></row>
|
|
<row><entry><literal><= (macaddr8,macaddr8)</literal></entry></row>
|
|
<row><entry><literal>> (macaddr8,macaddr8)</literal></entry></row>
|
|
<row><entry><literal>>= (macaddr8,macaddr8)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>macaddr8_minmax_multi_ops</literal></entry>
|
|
<entry><literal>= (macaddr8,macaddr8)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (macaddr8,macaddr8)</literal></entry></row>
|
|
<row><entry><literal><= (macaddr8,macaddr8)</literal></entry></row>
|
|
<row><entry><literal>> (macaddr8,macaddr8)</literal></entry></row>
|
|
<row><entry><literal>>= (macaddr8,macaddr8)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle"><literal>name_bloom_ops</literal></entry>
|
|
<entry><literal>= (name,name)</literal></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>name_minmax_ops</literal></entry>
|
|
<entry><literal>= (name,name)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (name,name)</literal></entry></row>
|
|
<row><entry><literal><= (name,name)</literal></entry></row>
|
|
<row><entry><literal>> (name,name)</literal></entry></row>
|
|
<row><entry><literal>>= (name,name)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle"><literal>numeric_bloom_ops</literal></entry>
|
|
<entry><literal>= (numeric,numeric)</literal></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>numeric_minmax_ops</literal></entry>
|
|
<entry><literal>= (numeric,numeric)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (numeric,numeric)</literal></entry></row>
|
|
<row><entry><literal><= (numeric,numeric)</literal></entry></row>
|
|
<row><entry><literal>> (numeric,numeric)</literal></entry></row>
|
|
<row><entry><literal>>= (numeric,numeric)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>numeric_minmax_multi_ops</literal></entry>
|
|
<entry><literal>= (numeric,numeric)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (numeric,numeric)</literal></entry></row>
|
|
<row><entry><literal><= (numeric,numeric)</literal></entry></row>
|
|
<row><entry><literal>> (numeric,numeric)</literal></entry></row>
|
|
<row><entry><literal>>= (numeric,numeric)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle"><literal>oid_bloom_ops</literal></entry>
|
|
<entry><literal>= (oid,oid)</literal></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>oid_minmax_ops</literal></entry>
|
|
<entry><literal>= (oid,oid)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (oid,oid)</literal></entry></row>
|
|
<row><entry><literal>> (oid,oid)</literal></entry></row>
|
|
<row><entry><literal><= (oid,oid)</literal></entry></row>
|
|
<row><entry><literal>>= (oid,oid)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>oid_minmax_multi_ops</literal></entry>
|
|
<entry><literal>= (oid,oid)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (oid,oid)</literal></entry></row>
|
|
<row><entry><literal>> (oid,oid)</literal></entry></row>
|
|
<row><entry><literal><= (oid,oid)</literal></entry></row>
|
|
<row><entry><literal>>= (oid,oid)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle"><literal>pg_lsn_bloom_ops</literal></entry>
|
|
<entry><literal>= (pg_lsn,pg_lsn)</literal></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>pg_lsn_minmax_ops</literal></entry>
|
|
<entry><literal>= (pg_lsn,pg_lsn)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (pg_lsn,pg_lsn)</literal></entry></row>
|
|
<row><entry><literal>> (pg_lsn,pg_lsn)</literal></entry></row>
|
|
<row><entry><literal><= (pg_lsn,pg_lsn)</literal></entry></row>
|
|
<row><entry><literal>>= (pg_lsn,pg_lsn)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>pg_lsn_minmax_multi_ops</literal></entry>
|
|
<entry><literal>= (pg_lsn,pg_lsn)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (pg_lsn,pg_lsn)</literal></entry></row>
|
|
<row><entry><literal>> (pg_lsn,pg_lsn)</literal></entry></row>
|
|
<row><entry><literal><= (pg_lsn,pg_lsn)</literal></entry></row>
|
|
<row><entry><literal>>= (pg_lsn,pg_lsn)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="13"><literal>range_inclusion_ops</literal></entry>
|
|
<entry><literal>= (anyrange,anyrange)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (anyrange,anyrange)</literal></entry></row>
|
|
<row><entry><literal><= (anyrange,anyrange)</literal></entry></row>
|
|
<row><entry><literal>>= (anyrange,anyrange)</literal></entry></row>
|
|
<row><entry><literal>> (anyrange,anyrange)</literal></entry></row>
|
|
<row><entry><literal>&& (anyrange,anyrange)</literal></entry></row>
|
|
<row><entry><literal>@> (anyrange,anyelement)</literal></entry></row>
|
|
<row><entry><literal>@> (anyrange,anyrange)</literal></entry></row>
|
|
<row><entry><literal><@ (anyrange,anyrange)</literal></entry></row>
|
|
<row><entry><literal><< (anyrange,anyrange)</literal></entry></row>
|
|
<row><entry><literal>>> (anyrange,anyrange)</literal></entry></row>
|
|
<row><entry><literal>&< (anyrange,anyrange)</literal></entry></row>
|
|
<row><entry><literal>&> (anyrange,anyrange)</literal></entry></row>
|
|
<row><entry><literal>-|- (anyrange,anyrange)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle"><literal>text_bloom_ops</literal></entry>
|
|
<entry><literal>= (text,text)</literal></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>text_minmax_ops</literal></entry>
|
|
<entry><literal>= (text,text)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (text,text)</literal></entry></row>
|
|
<row><entry><literal><= (text,text)</literal></entry></row>
|
|
<row><entry><literal>> (text,text)</literal></entry></row>
|
|
<row><entry><literal>>= (text,text)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle"><literal>tid_bloom_ops</literal></entry>
|
|
<entry><literal>= (tid,tid)</literal></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>tid_minmax_ops</literal></entry>
|
|
<entry><literal>= (tid,tid)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (tid,tid)</literal></entry></row>
|
|
<row><entry><literal>> (tid,tid)</literal></entry></row>
|
|
<row><entry><literal><= (tid,tid)</literal></entry></row>
|
|
<row><entry><literal>>= (tid,tid)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>tid_minmax_multi_ops</literal></entry>
|
|
<entry><literal>= (tid,tid)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (tid,tid)</literal></entry></row>
|
|
<row><entry><literal>> (tid,tid)</literal></entry></row>
|
|
<row><entry><literal><= (tid,tid)</literal></entry></row>
|
|
<row><entry><literal>>= (tid,tid)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle"><literal>timestamp_bloom_ops</literal></entry>
|
|
<entry><literal>= (timestamp,timestamp)</literal></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>timestamp_minmax_ops</literal></entry>
|
|
<entry><literal>= (timestamp,timestamp)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (timestamp,timestamp)</literal></entry></row>
|
|
<row><entry><literal><= (timestamp,timestamp)</literal></entry></row>
|
|
<row><entry><literal>> (timestamp,timestamp)</literal></entry></row>
|
|
<row><entry><literal>>= (timestamp,timestamp)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>timestamp_minmax_multi_ops</literal></entry>
|
|
<entry><literal>= (timestamp,timestamp)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (timestamp,timestamp)</literal></entry></row>
|
|
<row><entry><literal><= (timestamp,timestamp)</literal></entry></row>
|
|
<row><entry><literal>> (timestamp,timestamp)</literal></entry></row>
|
|
<row><entry><literal>>= (timestamp,timestamp)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle"><literal>timestamptz_bloom_ops</literal></entry>
|
|
<entry><literal>= (timestamptz,timestamptz)</literal></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>timestamptz_minmax_ops</literal></entry>
|
|
<entry><literal>= (timestamptz,timestamptz)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (timestamptz,timestamptz)</literal></entry></row>
|
|
<row><entry><literal><= (timestamptz,timestamptz)</literal></entry></row>
|
|
<row><entry><literal>> (timestamptz,timestamptz)</literal></entry></row>
|
|
<row><entry><literal>>= (timestamptz,timestamptz)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>timestamptz_minmax_multi_ops</literal></entry>
|
|
<entry><literal>= (timestamptz,timestamptz)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (timestamptz,timestamptz)</literal></entry></row>
|
|
<row><entry><literal><= (timestamptz,timestamptz)</literal></entry></row>
|
|
<row><entry><literal>> (timestamptz,timestamptz)</literal></entry></row>
|
|
<row><entry><literal>>= (timestamptz,timestamptz)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle"><literal>time_bloom_ops</literal></entry>
|
|
<entry><literal>= (time,time)</literal></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>time_minmax_ops</literal></entry>
|
|
<entry><literal>= (time,time)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (time,time)</literal></entry></row>
|
|
<row><entry><literal><= (time,time)</literal></entry></row>
|
|
<row><entry><literal>> (time,time)</literal></entry></row>
|
|
<row><entry><literal>>= (time,time)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>time_minmax_multi_ops</literal></entry>
|
|
<entry><literal>= (time,time)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (time,time)</literal></entry></row>
|
|
<row><entry><literal><= (time,time)</literal></entry></row>
|
|
<row><entry><literal>> (time,time)</literal></entry></row>
|
|
<row><entry><literal>>= (time,time)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle"><literal>timetz_bloom_ops</literal></entry>
|
|
<entry><literal>= (timetz,timetz)</literal></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>timetz_minmax_ops</literal></entry>
|
|
<entry><literal>= (timetz,timetz)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (timetz,timetz)</literal></entry></row>
|
|
<row><entry><literal><= (timetz,timetz)</literal></entry></row>
|
|
<row><entry><literal>> (timetz,timetz)</literal></entry></row>
|
|
<row><entry><literal>>= (timetz,timetz)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>timetz_minmax_multi_ops</literal></entry>
|
|
<entry><literal>= (timetz,timetz)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (timetz,timetz)</literal></entry></row>
|
|
<row><entry><literal><= (timetz,timetz)</literal></entry></row>
|
|
<row><entry><literal>> (timetz,timetz)</literal></entry></row>
|
|
<row><entry><literal>>= (timetz,timetz)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle"><literal>uuid_bloom_ops</literal></entry>
|
|
<entry><literal>= (uuid,uuid)</literal></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>uuid_minmax_ops</literal></entry>
|
|
<entry><literal>= (uuid,uuid)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (uuid,uuid)</literal></entry></row>
|
|
<row><entry><literal>> (uuid,uuid)</literal></entry></row>
|
|
<row><entry><literal><= (uuid,uuid)</literal></entry></row>
|
|
<row><entry><literal>>= (uuid,uuid)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>uuid_minmax_multi_ops</literal></entry>
|
|
<entry><literal>= (uuid,uuid)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (uuid,uuid)</literal></entry></row>
|
|
<row><entry><literal>> (uuid,uuid)</literal></entry></row>
|
|
<row><entry><literal><= (uuid,uuid)</literal></entry></row>
|
|
<row><entry><literal>>= (uuid,uuid)</literal></entry></row>
|
|
|
|
<row>
|
|
<entry valign="middle" morerows="4"><literal>varbit_minmax_ops</literal></entry>
|
|
<entry><literal>= (varbit,varbit)</literal></entry>
|
|
</row>
|
|
<row><entry><literal>< (varbit,varbit)</literal></entry></row>
|
|
<row><entry><literal>> (varbit,varbit)</literal></entry></row>
|
|
<row><entry><literal><= (varbit,varbit)</literal></entry></row>
|
|
<row><entry><literal>>= (varbit,varbit)</literal></entry></row>
|
|
</tbody>
|
|
</tgroup>
|
|
</table>
|
|
|
|
<sect2 id="brin-builtin-opclasses--parameters">
|
|
<title>Operator Class Parameters</title>
|
|
|
|
<para>
|
|
Some of the built-in operator classes allow specifying parameters affecting
|
|
behavior of the operator class. Each operator class has its own set of
|
|
allowed parameters. Only the <literal>bloom</literal> and <literal>minmax-multi</literal>
|
|
operator classes allow specifying parameters:
|
|
</para>
|
|
|
|
<para>
|
|
bloom operator classes accept these parameters:
|
|
</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><literal>n_distinct_per_range</literal></term>
|
|
<listitem>
|
|
<para>
|
|
Defines the estimated number of distinct non-null values in the block
|
|
range, used by <acronym>BRIN</acronym> bloom indexes for sizing of the
|
|
Bloom filter. It behaves similarly to <literal>n_distinct</literal> option
|
|
for <xref linkend="sql-altertable"/>. When set to a positive value,
|
|
each block range is assumed to contain this number of distinct non-null
|
|
values. When set to a negative value, which must be greater than or
|
|
equal to -1, the number of distinct non-null values is assumed to grow linearly with
|
|
the maximum possible number of tuples in the block range (about 290
|
|
rows per block). The default value is <literal>-0.1</literal>, and
|
|
the minimum number of distinct non-null values is <literal>16</literal>.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><literal>false_positive_rate</literal></term>
|
|
<listitem>
|
|
<para>
|
|
Defines the desired false positive rate used by <acronym>BRIN</acronym>
|
|
bloom indexes for sizing of the Bloom filter. The values must be
|
|
between 0.0001 and 0.25. The default value is 0.01, which is 1% false
|
|
positive rate.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
</variablelist>
|
|
|
|
<para>
|
|
minmax-multi operator classes accept these parameters:
|
|
</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><literal>values_per_range</literal></term>
|
|
<listitem>
|
|
<para>
|
|
Defines the maximum number of values stored by <acronym>BRIN</acronym>
|
|
minmax indexes to summarize a block range. Each value may represent
|
|
either a point, or a boundary of an interval. Values must be between
|
|
8 and 256, and the default value is 32.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
</variablelist>
|
|
</sect2>
|
|
|
|
</sect1>
|
|
|
|
<sect1 id="brin-extensibility">
|
|
<title>Extensibility</title>
|
|
|
|
<para>
|
|
The <acronym>BRIN</acronym> interface has a high level of abstraction,
|
|
requiring the access method implementer only to implement the semantics
|
|
of the data type being accessed. The <acronym>BRIN</acronym> layer
|
|
itself takes care of concurrency, logging and searching the index structure.
|
|
</para>
|
|
|
|
<para>
|
|
All it takes to get a <acronym>BRIN</acronym> access method working is to
|
|
implement a few user-defined methods, which define the behavior of
|
|
summary values stored in the index and the way they interact with
|
|
scan keys.
|
|
In short, <acronym>BRIN</acronym> combines
|
|
extensibility with generality, code reuse, and a clean interface.
|
|
</para>
|
|
|
|
<para>
|
|
There are four methods that an operator class for <acronym>BRIN</acronym>
|
|
must provide:
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><function>BrinOpcInfo *opcInfo(Oid type_oid)</function></term>
|
|
<listitem>
|
|
<para>
|
|
Returns internal information about the indexed columns' summary data.
|
|
The return value must point to a palloc'd <structname>BrinOpcInfo</structname>,
|
|
which has this definition:
|
|
<programlisting>
|
|
typedef struct BrinOpcInfo
|
|
{
|
|
/* Number of columns stored in an index column of this opclass */
|
|
uint16 oi_nstored;
|
|
|
|
/* Opaque pointer for the opclass' private use */
|
|
void *oi_opaque;
|
|
|
|
/* Type cache entries of the stored columns */
|
|
TypeCacheEntry *oi_typcache[FLEXIBLE_ARRAY_MEMBER];
|
|
} BrinOpcInfo;
|
|
</programlisting>
|
|
<structname>BrinOpcInfo</structname>.<structfield>oi_opaque</structfield> can be used by the
|
|
operator class routines to pass information between support functions
|
|
during an index scan.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><function>bool consistent(BrinDesc *bdesc, BrinValues *column,
|
|
ScanKey *keys, int nkeys)</function></term>
|
|
<listitem>
|
|
<para>
|
|
Returns whether all the ScanKey entries are consistent with the given
|
|
indexed values for a range.
|
|
The attribute number to use is passed as part of the scan key.
|
|
Multiple scan keys for the same attribute may be passed at once; the
|
|
number of entries is determined by the <literal>nkeys</literal> parameter.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><function>bool consistent(BrinDesc *bdesc, BrinValues *column,
|
|
ScanKey key)</function></term>
|
|
<listitem>
|
|
<para>
|
|
Returns whether the ScanKey is consistent with the given indexed
|
|
values for a range.
|
|
The attribute number to use is passed as part of the scan key.
|
|
This is an older backward-compatible variant of the consistent function.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><function>bool addValue(BrinDesc *bdesc, BrinValues *column,
|
|
Datum newval, bool isnull)</function></term>
|
|
<listitem>
|
|
<para>
|
|
Given an index tuple and an indexed value, modifies the indicated
|
|
attribute of the tuple so that it additionally represents the new value.
|
|
If any modification was done to the tuple, <literal>true</literal> is
|
|
returned.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><function>bool unionTuples(BrinDesc *bdesc, BrinValues *a,
|
|
BrinValues *b)</function></term>
|
|
<listitem>
|
|
<para>
|
|
Consolidates two index tuples. Given two index tuples, modifies the
|
|
indicated attribute of the first of them so that it represents both tuples.
|
|
The second tuple is not modified.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
|
|
An operator class for <acronym>BRIN</acronym> can optionally specify the
|
|
following method:
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><function>void options(local_relopts *relopts)</function></term>
|
|
<listitem>
|
|
<para>
|
|
Defines a set of user-visible parameters that control operator class
|
|
behavior.
|
|
</para>
|
|
|
|
<para>
|
|
The <function>options</function> function is passed a pointer to a
|
|
<structname>local_relopts</structname> struct, which needs to be
|
|
filled with a set of operator class specific options. The options
|
|
can be accessed from other support functions using the
|
|
<literal>PG_HAS_OPCLASS_OPTIONS()</literal> and
|
|
<literal>PG_GET_OPCLASS_OPTIONS()</literal> macros.
|
|
</para>
|
|
|
|
<para>
|
|
Since both key extraction of indexed values and representation of the
|
|
key in <acronym>BRIN</acronym> are flexible, they may depend on
|
|
user-specified parameters.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
|
|
The core distribution includes support for four types of operator classes:
|
|
minmax, minmax-multi, inclusion and bloom. Operator class definitions
|
|
using them are shipped for in-core data types as appropriate. Additional
|
|
operator classes can be defined by the user for other data types using
|
|
equivalent definitions, without having to write any source code;
|
|
appropriate catalog entries being declared is enough. Note that
|
|
assumptions about the semantics of operator strategies are embedded in the
|
|
support functions' source code.
|
|
</para>
|
|
|
|
<para>
|
|
Operator classes that implement completely different semantics are also
|
|
possible, provided implementations of the four main support functions
|
|
described above are written. Note that backwards compatibility across major
|
|
releases is not guaranteed: for example, additional support functions might
|
|
be required in later releases.
|
|
</para>
|
|
|
|
<para>
|
|
To write an operator class for a data type that implements a totally
|
|
ordered set, it is possible to use the minmax support functions
|
|
alongside the corresponding operators, as shown in
|
|
<xref linkend="brin-extensibility-minmax-table"/>.
|
|
All operator class members (functions and operators) are mandatory.
|
|
</para>
|
|
|
|
<table id="brin-extensibility-minmax-table">
|
|
<title>Function and Support Numbers for Minmax Operator Classes</title>
|
|
<tgroup cols="2">
|
|
<colspec colname="col1" colwidth="1*"/>
|
|
<colspec colname="col2" colwidth="2*"/>
|
|
<thead>
|
|
<row>
|
|
<entry>Operator class member</entry>
|
|
<entry>Object</entry>
|
|
</row>
|
|
</thead>
|
|
<tbody>
|
|
<row>
|
|
<entry>Support Function 1</entry>
|
|
<entry>internal function <function>brin_minmax_opcinfo()</function></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Function 2</entry>
|
|
<entry>internal function <function>brin_minmax_add_value()</function></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Function 3</entry>
|
|
<entry>internal function <function>brin_minmax_consistent()</function></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Function 4</entry>
|
|
<entry>internal function <function>brin_minmax_union()</function></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 1</entry>
|
|
<entry>operator less-than</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 2</entry>
|
|
<entry>operator less-than-or-equal-to</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 3</entry>
|
|
<entry>operator equal-to</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 4</entry>
|
|
<entry>operator greater-than-or-equal-to</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 5</entry>
|
|
<entry>operator greater-than</entry>
|
|
</row>
|
|
</tbody>
|
|
</tgroup>
|
|
</table>
|
|
|
|
<para>
|
|
To write an operator class for a complex data type which has values
|
|
included within another type, it's possible to use the inclusion support
|
|
functions alongside the corresponding operators, as shown
|
|
in <xref linkend="brin-extensibility-inclusion-table"/>. It requires
|
|
only a single additional function, which can be written in any language.
|
|
More functions can be defined for additional functionality. All operators
|
|
are optional. Some operators require other operators, as shown as
|
|
dependencies on the table.
|
|
</para>
|
|
|
|
<table id="brin-extensibility-inclusion-table">
|
|
<title>Function and Support Numbers for Inclusion Operator Classes</title>
|
|
<tgroup cols="3">
|
|
<colspec colname="col1" colwidth="1*"/>
|
|
<colspec colname="col2" colwidth="2*"/>
|
|
<colspec colname="col3" colwidth="1*"/>
|
|
<thead>
|
|
<row>
|
|
<entry>Operator class member</entry>
|
|
<entry>Object</entry>
|
|
<entry>Dependency</entry>
|
|
</row>
|
|
</thead>
|
|
<tbody>
|
|
<row>
|
|
<entry>Support Function 1</entry>
|
|
<entry>internal function <function>brin_inclusion_opcinfo()</function></entry>
|
|
<entry></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Function 2</entry>
|
|
<entry>internal function <function>brin_inclusion_add_value()</function></entry>
|
|
<entry></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Function 3</entry>
|
|
<entry>internal function <function>brin_inclusion_consistent()</function></entry>
|
|
<entry></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Function 4</entry>
|
|
<entry>internal function <function>brin_inclusion_union()</function></entry>
|
|
<entry></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Function 11</entry>
|
|
<entry>function to merge two elements</entry>
|
|
<entry></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Function 12</entry>
|
|
<entry>optional function to check whether two elements are mergeable</entry>
|
|
<entry></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Function 13</entry>
|
|
<entry>optional function to check if an element is contained within another</entry>
|
|
<entry></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Function 14</entry>
|
|
<entry>optional function to check whether an element is empty</entry>
|
|
<entry></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 1</entry>
|
|
<entry>operator left-of</entry>
|
|
<entry>Operator Strategy 4</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 2</entry>
|
|
<entry>operator does-not-extend-to-the-right-of</entry>
|
|
<entry>Operator Strategy 5</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 3</entry>
|
|
<entry>operator overlaps</entry>
|
|
<entry></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 4</entry>
|
|
<entry>operator does-not-extend-to-the-left-of</entry>
|
|
<entry>Operator Strategy 1</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 5</entry>
|
|
<entry>operator right-of</entry>
|
|
<entry>Operator Strategy 2</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 6, 18</entry>
|
|
<entry>operator same-as-or-equal-to</entry>
|
|
<entry>Operator Strategy 7</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 7, 16, 24, 25</entry>
|
|
<entry>operator contains-or-equal-to</entry>
|
|
<entry></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 8, 26, 27</entry>
|
|
<entry>operator is-contained-by-or-equal-to</entry>
|
|
<entry>Operator Strategy 3</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 9</entry>
|
|
<entry>operator does-not-extend-above</entry>
|
|
<entry>Operator Strategy 11</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 10</entry>
|
|
<entry>operator is-below</entry>
|
|
<entry>Operator Strategy 12</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 11</entry>
|
|
<entry>operator is-above</entry>
|
|
<entry>Operator Strategy 9</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 12</entry>
|
|
<entry>operator does-not-extend-below</entry>
|
|
<entry>Operator Strategy 10</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 20</entry>
|
|
<entry>operator less-than</entry>
|
|
<entry>Operator Strategy 5</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 21</entry>
|
|
<entry>operator less-than-or-equal-to</entry>
|
|
<entry>Operator Strategy 5</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 22</entry>
|
|
<entry>operator greater-than</entry>
|
|
<entry>Operator Strategy 1</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 23</entry>
|
|
<entry>operator greater-than-or-equal-to</entry>
|
|
<entry>Operator Strategy 1</entry>
|
|
</row>
|
|
</tbody>
|
|
</tgroup>
|
|
</table>
|
|
|
|
<para>
|
|
Support function numbers 1 through 10 are reserved for the BRIN internal
|
|
functions, so the SQL level functions start with number 11. Support
|
|
function number 11 is the main function required to build the index.
|
|
It should accept two arguments with the same data type as the operator class,
|
|
and return the union of them. The inclusion operator class can store union
|
|
values with different data types if it is defined with the
|
|
<literal>STORAGE</literal> parameter. The return value of the union
|
|
function should match the <literal>STORAGE</literal> data type.
|
|
</para>
|
|
|
|
<para>
|
|
Support function numbers 12 and 14 are provided to support
|
|
irregularities of built-in data types. Function number 12
|
|
is used to support network addresses from different families which
|
|
are not mergeable. Function number 14 is used to support
|
|
empty ranges. Function number 13 is an optional but
|
|
recommended one, which allows the new value to be checked before
|
|
it is passed to the union function. As the BRIN framework can shortcut
|
|
some operations when the union is not changed, using this
|
|
function can improve index performance.
|
|
</para>
|
|
|
|
<para>
|
|
To write an operator class for a data type that implements only an equality
|
|
operator and supports hashing, it is possible to use the bloom support procedures
|
|
alongside the corresponding operators, as shown in
|
|
<xref linkend="brin-extensibility-bloom-table"/>.
|
|
All operator class members (procedures and operators) are mandatory.
|
|
</para>
|
|
|
|
<table id="brin-extensibility-bloom-table">
|
|
<title>Procedure and Support Numbers for Bloom Operator Classes</title>
|
|
<tgroup cols="2">
|
|
<thead>
|
|
<row>
|
|
<entry>Operator class member</entry>
|
|
<entry>Object</entry>
|
|
</row>
|
|
</thead>
|
|
<tbody>
|
|
<row>
|
|
<entry>Support Procedure 1</entry>
|
|
<entry>internal function <function>brin_bloom_opcinfo()</function></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Procedure 2</entry>
|
|
<entry>internal function <function>brin_bloom_add_value()</function></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Procedure 3</entry>
|
|
<entry>internal function <function>brin_bloom_consistent()</function></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Procedure 4</entry>
|
|
<entry>internal function <function>brin_bloom_union()</function></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Procedure 11</entry>
|
|
<entry>function to compute hash of an element</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 1</entry>
|
|
<entry>operator equal-to</entry>
|
|
</row>
|
|
</tbody>
|
|
</tgroup>
|
|
</table>
|
|
|
|
<para>
|
|
Support procedure numbers 1-10 are reserved for the BRIN internal
|
|
functions, so the SQL level functions start with number 11. Support
|
|
function number 11 is the main function required to build the index.
|
|
It should accept one argument with the same data type as the operator class,
|
|
and return a hash of the value.
|
|
</para>
|
|
|
|
<para>
|
|
The minmax-multi operator class is also intended for data types implementing
|
|
a totally ordered set, and may be seen as a simple extension of the minmax
|
|
operator class. While minmax operator class summarizes values from each block
|
|
range into a single contiguous interval, minmax-multi allows summarization
|
|
into multiple smaller intervals to improve handling of outlier values.
|
|
It is possible to use the minmax-multi support procedures alongside the
|
|
corresponding operators, as shown in
|
|
<xref linkend="brin-extensibility-minmax-multi-table"/>.
|
|
All operator class members (procedures and operators) are mandatory.
|
|
</para>
|
|
|
|
<table id="brin-extensibility-minmax-multi-table">
|
|
<title>Procedure and Support Numbers for minmax-multi Operator Classes</title>
|
|
<tgroup cols="2">
|
|
<thead>
|
|
<row>
|
|
<entry>Operator class member</entry>
|
|
<entry>Object</entry>
|
|
</row>
|
|
</thead>
|
|
<tbody>
|
|
<row>
|
|
<entry>Support Procedure 1</entry>
|
|
<entry>internal function <function>brin_minmax_multi_opcinfo()</function></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Procedure 2</entry>
|
|
<entry>internal function <function>brin_minmax_multi_add_value()</function></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Procedure 3</entry>
|
|
<entry>internal function <function>brin_minmax_multi_consistent()</function></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Procedure 4</entry>
|
|
<entry>internal function <function>brin_minmax_multi_union()</function></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Support Procedure 11</entry>
|
|
<entry>function to compute distance between two values (length of a range)</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 1</entry>
|
|
<entry>operator less-than</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 2</entry>
|
|
<entry>operator less-than-or-equal-to</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 3</entry>
|
|
<entry>operator equal-to</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 4</entry>
|
|
<entry>operator greater-than-or-equal-to</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Operator Strategy 5</entry>
|
|
<entry>operator greater-than</entry>
|
|
</row>
|
|
</tbody>
|
|
</tgroup>
|
|
</table>
|
|
|
|
<para>
|
|
Both minmax and inclusion operator classes support cross-data-type
|
|
operators, though with these the dependencies become more complicated.
|
|
The minmax operator class requires a full set of operators to be
|
|
defined with both arguments having the same data type. It allows
|
|
additional data types to be supported by defining extra sets
|
|
of operators. Inclusion operator class operator strategies are dependent
|
|
on another operator strategy as shown in
|
|
<xref linkend="brin-extensibility-inclusion-table"/>, or the same
|
|
operator strategy as themselves. They require the dependency
|
|
operator to be defined with the <literal>STORAGE</literal> data type as the
|
|
left-hand-side argument and the other supported data type to be the
|
|
right-hand-side argument of the supported operator. See
|
|
<literal>float4_minmax_ops</literal> as an example of minmax, and
|
|
<literal>box_inclusion_ops</literal> as an example of inclusion.
|
|
</para>
|
|
</sect1>
|
|
</chapter>
|