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diff --git a/doc/src/sgml/brin.sgml b/doc/src/sgml/brin.sgml new file mode 100644 index 0000000..9c5ffcd --- /dev/null +++ b/doc/src/sgml/brin.sgml @@ -0,0 +1,1342 @@ +<!-- doc/src/sgml/brin.sgml --> + +<chapter id="brin"> +<title>BRIN Indexes</title> + + <indexterm> + <primary>index</primary> + <secondary>BRIN</secondary> + </indexterm> + +<sect1 id="brin-intro"> + <title>Introduction</title> + + <para> + <acronym>BRIN</acronym> stands for Block Range Index. + <acronym>BRIN</acronym> is designed for handling very large tables + in which certain columns have some natural correlation with their + physical location within the table. + </para> + + <para> + <acronym>BRIN</acronym> works in terms of <firstterm>block ranges</firstterm> + (or <quote>page ranges</quote>). + A block range is a group of pages that are physically + adjacent in the table; for each block range, some summary info is stored + by the index. + For example, a table storing a store's sale orders might have + a date column on which each order was placed, and most of the time + the entries for earlier orders will appear earlier in the table as well; + a table storing a ZIP code column might have all codes for a city + grouped together naturally. + </para> + + <para> + <acronym>BRIN</acronym> indexes can satisfy queries via regular bitmap + index scans, and will return all tuples in all pages within each range if + the summary info stored by the index is <firstterm>consistent</firstterm> with the + query conditions. + The query executor is in charge of rechecking these tuples and discarding + those that do not match the query conditions — in other words, these + indexes are lossy. + Because a <acronym>BRIN</acronym> index is very small, scanning the index + adds little overhead compared to a sequential scan, but may avoid scanning + large parts of the table that are known not to contain matching tuples. + </para> + + <para> + The specific data that a <acronym>BRIN</acronym> index will store, + as well as the specific queries that the index will be able to satisfy, + depend on the operator class selected for each column of the index. + Data types having a linear sort order can have operator classes that + store the minimum and maximum value within each block range, for instance; + geometrical types might store the bounding box for all the objects + in the block range. + </para> + + <para> + The size of the block range is determined at index creation time by + the <literal>pages_per_range</literal> storage parameter. The number of index + entries will be equal to the size of the relation in pages divided by + the selected value for <literal>pages_per_range</literal>. Therefore, the smaller + the number, the larger the index becomes (because of the need to + store more index entries), but at the same time the summary data stored can + be more precise and more data blocks can be skipped during an index scan. + </para> + + <sect2 id="brin-operation"> + <title>Index Maintenance</title> + + <para> + At the time of creation, all existing heap pages are scanned and a + summary index tuple is created for each range, including the + possibly-incomplete range at the end. + As new pages are filled with data, page ranges that are already + summarized will cause the summary information to be updated with data + from the new tuples. + When a new page is created that does not fall within the last + summarized range, the range that the new page belongs to + does not automatically acquire a summary tuple; + those tuples remain unsummarized until a summarization run is + invoked later, creating the initial summary for that range. + </para> + + <para> + There are several ways to trigger the initial summarization of a page range. + If the table is vacuumed, either manually or by + <link linkend="autovacuum">autovacuum</link>, all existing unsummarized + page ranges are summarized. + Also, if the index's + <xref linkend="index-reloption-autosummarize"/> parameter is enabled, + which it isn't by default, + whenever autovacuum runs in that database, summarization will occur for all + unsummarized page ranges that have been filled, + regardless of whether the table itself is processed by autovacuum; see below. + </para> + + <para> + Lastly, the following functions can be used: + <simplelist> + <member> + <function>brin_summarize_new_values(regclass)</function> + which summarizes all unsummarized ranges; + </member> + <member> + <function>brin_summarize_range(regclass, bigint)</function> + which summarizes only the range containing the given page, + if it is unsummarized. + </member> + </simplelist> + </para> + + <para> + When autosummarization is enabled, a request is sent to + <literal>autovacuum</literal> to execute a targeted summarization + for a block range when an insertion is detected for the first item + of the first page of the next block range, + to be fulfilled the next time an autovacuum + worker finishes running in the + same database. If the request queue is full, the request is not recorded + and a message is sent to the server log: +<screen> +LOG: request for BRIN range summarization for index "brin_wi_idx" page 128 was not recorded +</screen> + When this happens, the range will remain unsummarized until the next + regular vacuum run on the table, or one of the functions mentioned above + are invoked. + </para> + + <para> + Conversely, a range can be de-summarized using the + <function>brin_desummarize_range(regclass, bigint)</function> function, + which is useful when the index tuple is no longer a very good + representation because the existing values have changed. + See <xref linkend="functions-admin-index"/> for details. + </para> + + </sect2> +</sect1> + +<sect1 id="brin-builtin-opclasses"> + <title>Built-in Operator Classes</title> + + <para> + The core <productname>PostgreSQL</productname> distribution + includes the <acronym>BRIN</acronym> operator classes shown in + <xref linkend="brin-builtin-opclasses-table"/>. + </para> + + <para> + The <firstterm>minmax</firstterm> + operator classes store the minimum and the maximum values appearing + in the indexed column within the range. The <firstterm>inclusion</firstterm> + operator classes store a value which includes the values in the indexed + column within the range. The <firstterm>bloom</firstterm> operator + classes build a Bloom filter for all values in the range. The + <firstterm>minmax-multi</firstterm> operator classes store multiple + minimum and maximum values, representing values appearing in the indexed + column within the range. + </para> + + <table id="brin-builtin-opclasses-table"> + <title>Built-in <acronym>BRIN</acronym> Operator Classes</title> + <tgroup cols="2"> + <thead> + <row> + <entry>Name</entry> + <entry>Indexable Operators</entry> + </row> + </thead> + <tbody> + <row> + <entry valign="middle" morerows="4"><literal>bit_minmax_ops</literal></entry> + <entry><literal>= (bit,bit)</literal></entry> + </row> + <row><entry><literal>< (bit,bit)</literal></entry></row> + <row><entry><literal>> (bit,bit)</literal></entry></row> + <row><entry><literal><= (bit,bit)</literal></entry></row> + <row><entry><literal>>= (bit,bit)</literal></entry></row> + + <row> + <entry valign="middle" morerows="12"><literal>box_inclusion_ops</literal></entry> + <entry><literal>@> (box,point)</literal></entry> + </row> + <row><entry><literal><< (box,box)</literal></entry></row> + <row><entry><literal>&< (box,box)</literal></entry></row> + <row><entry><literal>&> (box,box)</literal></entry></row> + <row><entry><literal>>> (box,box)</literal></entry></row> + <row><entry><literal><@ (box,box)</literal></entry></row> + <row><entry><literal>@> (box,box)</literal></entry></row> + <row><entry><literal>~= (box,box)</literal></entry></row> + <row><entry><literal>&& (box,box)</literal></entry></row> + <row><entry><literal><<| (box,box)</literal></entry></row> + <row><entry><literal>&<| (box,box)</literal></entry></row> + <row><entry><literal>|&> (box,box)</literal></entry></row> + <row><entry><literal>|>> (box,box)</literal></entry></row> + + <row> + <entry valign="middle"><literal>bpchar_bloom_ops</literal></entry> + <entry><literal>= (character,character)</literal></entry> + </row> + + <row> + <entry valign="middle" morerows="4"><literal>bpchar_minmax_ops</literal></entry> + <entry><literal>= (character,character)</literal></entry> + </row> + <row><entry><literal>< (character,character)</literal></entry></row> + <row><entry><literal><= (character,character)</literal></entry></row> + <row><entry><literal>> (character,character)</literal></entry></row> + <row><entry><literal>>= (character,character)</literal></entry></row> + + <row> + <entry valign="middle"><literal>bytea_bloom_ops</literal></entry> + <entry><literal>= (bytea,bytea)</literal></entry> + </row> + + <row> + <entry valign="middle" morerows="4"><literal>bytea_minmax_ops</literal></entry> + <entry><literal>= (bytea,bytea)</literal></entry> + </row> + <row><entry><literal>< (bytea,bytea)</literal></entry></row> + <row><entry><literal><= (bytea,bytea)</literal></entry></row> + <row><entry><literal>> (bytea,bytea)</literal></entry></row> + <row><entry><literal>>= (bytea,bytea)</literal></entry></row> + + <row> + <entry valign="middle"><literal>char_bloom_ops</literal></entry> + <entry><literal>= ("char","char")</literal></entry> + </row> + + <row> + <entry valign="middle" morerows="4"><literal>char_minmax_ops</literal></entry> + <entry><literal>= ("char","char")</literal></entry> + </row> + <row><entry><literal>< ("char","char")</literal></entry></row> + <row><entry><literal><= ("char","char")</literal></entry></row> + <row><entry><literal>> ("char","char")</literal></entry></row> + <row><entry><literal>>= ("char","char")</literal></entry></row> + + <row> + <entry valign="middle"><literal>date_bloom_ops</literal></entry> + <entry><literal>= (date,date)</literal></entry> + </row> + + <row> + <entry valign="middle" morerows="4"><literal>date_minmax_ops</literal></entry> + <entry><literal>= (date,date)</literal></entry> + </row> + <row><entry><literal>< (date,date)</literal></entry></row> + <row><entry><literal><= (date,date)</literal></entry></row> + <row><entry><literal>> (date,date)</literal></entry></row> + <row><entry><literal>>= (date,date)</literal></entry></row> + + <row> + <entry valign="middle" morerows="4"><literal>date_minmax_multi_ops</literal></entry> + <entry><literal>= (date,date)</literal></entry> + </row> + <row><entry><literal>< (date,date)</literal></entry></row> + <row><entry><literal><= (date,date)</literal></entry></row> + <row><entry><literal>> (date,date)</literal></entry></row> + <row><entry><literal>>= (date,date)</literal></entry></row> + + <row> + <entry valign="middle"><literal>float4_bloom_ops</literal></entry> + <entry><literal>= (float4,float4)</literal></entry> + </row> + + <row> + <entry valign="middle" morerows="4"><literal>float4_minmax_ops</literal></entry> + <entry><literal>= (float4,float4)</literal></entry> + </row> + <row><entry><literal>< (float4,float4)</literal></entry></row> + <row><entry><literal>> (float4,float4)</literal></entry></row> + <row><entry><literal><= (float4,float4)</literal></entry></row> + <row><entry><literal>>= (float4,float4)</literal></entry></row> + + <row> + <entry valign="middle" morerows="4"><literal>float4_minmax_multi_ops</literal></entry> + <entry><literal>= (float4,float4)</literal></entry> + </row> + <row><entry><literal>< (float4,float4)</literal></entry></row> + <row><entry><literal>> (float4,float4)</literal></entry></row> + <row><entry><literal><= (float4,float4)</literal></entry></row> + <row><entry><literal>>= (float4,float4)</literal></entry></row> + + <row> + <entry valign="middle"><literal>float8_bloom_ops</literal></entry> + <entry><literal>= (float8,float8)</literal></entry> + </row> + + <row> + <entry valign="middle" morerows="4"><literal>float8_minmax_ops</literal></entry> + <entry><literal>= (float8,float8)</literal></entry> + </row> + <row><entry><literal>< (float8,float8)</literal></entry></row> + <row><entry><literal><= (float8,float8)</literal></entry></row> + <row><entry><literal>> (float8,float8)</literal></entry></row> + <row><entry><literal>>= (float8,float8)</literal></entry></row> + + <row> + <entry valign="middle" morerows="4"><literal>float8_minmax_multi_ops</literal></entry> + <entry><literal>= (float8,float8)</literal></entry> + </row> + <row><entry><literal>< (float8,float8)</literal></entry></row> + <row><entry><literal><= (float8,float8)</literal></entry></row> + <row><entry><literal>> (float8,float8)</literal></entry></row> + <row><entry><literal>>= (float8,float8)</literal></entry></row> + + <row> + <entry valign="middle" morerows="5"><literal>inet_inclusion_ops</literal></entry> + <entry><literal><< (inet,inet)</literal></entry> + </row> + <row><entry><literal><<= (inet,inet)</literal></entry></row> + <row><entry><literal>>> (inet,inet)</literal></entry></row> + <row><entry><literal>>>= (inet,inet)</literal></entry></row> + <row><entry><literal>= (inet,inet)</literal></entry></row> + <row><entry><literal>&& (inet,inet)</literal></entry></row> + + <row> + <entry valign="middle"><literal>inet_bloom_ops</literal></entry> + <entry><literal>= (inet,inet)</literal></entry> + </row> + + <row> + <entry valign="middle" morerows="4"><literal>inet_minmax_ops</literal></entry> + <entry><literal>= (inet,inet)</literal></entry> + </row> + <row><entry><literal>< (inet,inet)</literal></entry></row> + <row><entry><literal><= (inet,inet)</literal></entry></row> + <row><entry><literal>> (inet,inet)</literal></entry></row> + <row><entry><literal>>= (inet,inet)</literal></entry></row> + + <row> + <entry valign="middle" morerows="4"><literal>inet_minmax_multi_ops</literal></entry> + <entry><literal>= (inet,inet)</literal></entry> + </row> + <row><entry><literal>< (inet,inet)</literal></entry></row> + <row><entry><literal><= (inet,inet)</literal></entry></row> + <row><entry><literal>> (inet,inet)</literal></entry></row> + <row><entry><literal>>= (inet,inet)</literal></entry></row> + + <row> + <entry valign="middle"><literal>int2_bloom_ops</literal></entry> + <entry><literal>= (int2,int2)</literal></entry> + </row> + + <row> + <entry valign="middle" morerows="4"><literal>int2_minmax_ops</literal></entry> + <entry><literal>= (int2,int2)</literal></entry> + </row> + <row><entry><literal>< (int2,int2)</literal></entry></row> + <row><entry><literal>> (int2,int2)</literal></entry></row> + <row><entry><literal><= (int2,int2)</literal></entry></row> + <row><entry><literal>>= (int2,int2)</literal></entry></row> + + <row> + <entry valign="middle" morerows="4"><literal>int2_minmax_multi_ops</literal></entry> + <entry><literal>= (int2,int2)</literal></entry> + </row> + <row><entry><literal>< (int2,int2)</literal></entry></row> + <row><entry><literal>> (int2,int2)</literal></entry></row> + <row><entry><literal><= (int2,int2)</literal></entry></row> + <row><entry><literal>>= (int2,int2)</literal></entry></row> + + <row> + <entry valign="middle"><literal>int4_bloom_ops</literal></entry> + <entry><literal>= (int4,int4)</literal></entry> + </row> + + <row> + <entry valign="middle" morerows="4"><literal>int4_minmax_ops</literal></entry> + <entry><literal>= (int4,int4)</literal></entry> + </row> + <row><entry><literal>< (int4,int4)</literal></entry></row> + <row><entry><literal>> (int4,int4)</literal></entry></row> + <row><entry><literal><= (int4,int4)</literal></entry></row> + <row><entry><literal>>= (int4,int4)</literal></entry></row> + + <row> + <entry valign="middle" morerows="4"><literal>int4_minmax_multi_ops</literal></entry> + <entry><literal>= (int4,int4)</literal></entry> + </row> + <row><entry><literal>< (int4,int4)</literal></entry></row> + <row><entry><literal>> (int4,int4)</literal></entry></row> + <row><entry><literal><= (int4,int4)</literal></entry></row> + <row><entry><literal>>= (int4,int4)</literal></entry></row> + + <row> + <entry valign="middle"><literal>int8_bloom_ops</literal></entry> + <entry><literal>= (bigint,bigint)</literal></entry> + </row> + + <row> + <entry valign="middle" morerows="4"><literal>int8_minmax_ops</literal></entry> + <entry><literal>= (bigint,bigint)</literal></entry> + </row> + <row><entry><literal>< (bigint,bigint)</literal></entry></row> + <row><entry><literal>> (bigint,bigint)</literal></entry></row> + <row><entry><literal><= (bigint,bigint)</literal></entry></row> + <row><entry><literal>>= (bigint,bigint)</literal></entry></row> + + <row> + <entry valign="middle" morerows="4"><literal>int8_minmax_multi_ops</literal></entry> + <entry><literal>= (bigint,bigint)</literal></entry> + </row> + <row><entry><literal>< (bigint,bigint)</literal></entry></row> + <row><entry><literal>> (bigint,bigint)</literal></entry></row> + <row><entry><literal><= (bigint,bigint)</literal></entry></row> + <row><entry><literal>>= (bigint,bigint)</literal></entry></row> + + <row> + <entry valign="middle"><literal>interval_bloom_ops</literal></entry> + <entry><literal>= (interval,interval)</literal></entry> + </row> + + <row> + <entry valign="middle" morerows="4"><literal>interval_minmax_ops</literal></entry> + <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><literal>>= (interval,interval)</literal></entry></row> + + <row> + <entry valign="middle" morerows="4"><literal>interval_minmax_multi_ops</literal></entry> + <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><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 5</entry> + <entry>internal function <function>brin_bloom_options()</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 5</entry> + <entry>internal function <function>brin_minmax_multi_options()</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> |