mirror of https://github.com/postgres/postgres
Simplify pg_am representation of ordering-capable access methods:
provide just a boolean 'amcanorder', instead of fields that specify the sort operator strategy numbers. We have decided to require ordering-capable AMs to use btree-compatible strategy numbers, so the old fields are overkill (and indeed misleading about what's allowed).
This commit is contained in:
Tom Lane
parent
c82cc604f5
commit
fcf4b146c6
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@ -1,4 +1,4 @@
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<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.141 2007/01/09 02:14:09 tgl Exp $ -->
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<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.142 2007/01/20 23:13:01 tgl Exp $ -->
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<!--
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Documentation of the system catalogs, directed toward PostgreSQL developers
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-->
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@ -365,21 +365,10 @@
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</row>
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<row>
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<entry><structfield>amorderstrategy</structfield></entry>
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<entry><type>int2</type></entry>
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<entry><structfield>amcanorder</structfield></entry>
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<entry><type>bool</type></entry>
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<entry></entry>
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<entry>Zero if the index offers no sort order, otherwise the strategy
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number of the strategy operator that describes the default
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(<literal>ASC</>) sort order</entry>
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</row>
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<row>
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<entry><structfield>amdescorder</structfield></entry>
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<entry><type>int2</type></entry>
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<entry></entry>
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<entry>Zero if the index offers no sort order, otherwise the strategy
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number of the strategy operator that describes the <literal>DESC</>
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sort order</entry>
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<entry>Does the access method support ordered scans?</entry>
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</row>
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<row>
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@ -1,4 +1,4 @@
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<!-- $PostgreSQL: pgsql/doc/src/sgml/indexam.sgml,v 2.19 2006/12/23 00:43:08 tgl Exp $ -->
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<!-- $PostgreSQL: pgsql/doc/src/sgml/indexam.sgml,v 2.20 2007/01/20 23:13:01 tgl Exp $ -->
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<chapter id="indexam">
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<title>Index Access Method Interface Definition</title>
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@ -442,6 +442,15 @@ amrestrpos (IndexScanDesc scan);
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the scan keys to a <quote>normalized</> form.
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</para>
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<para>
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Some access methods return index entries in a well-defined order, others
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do not. If entries are returned in sorted order, the access method should
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set <structname>pg_am</>.<structfield>amcanorder</> true to indicate that
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it supports ordered scans.
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All such access methods must use btree-compatible strategy numbers for
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their equality and ordering operators.
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</para>
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<para>
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The <function>amgettuple</> function has a <literal>direction</> argument,
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which can be either <literal>ForwardScanDirection</> (the normal case)
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@ -451,8 +460,7 @@ amrestrpos (IndexScanDesc scan);
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the normal front-to-back direction, so <function>amgettuple</> must return
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the last matching tuple in the index, rather than the first one as it
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normally would. (This will only occur for access
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methods that advertise they support ordered scans by setting
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<structname>pg_am</>.<structfield>amorderstrategy</> nonzero.) After the
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methods that advertise they support ordered scans.) After the
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first call, <function>amgettuple</> must be prepared to advance the scan in
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either direction from the most recently returned entry.
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</para>
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@ -1,4 +1,4 @@
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<!-- $PostgreSQL: pgsql/doc/src/sgml/xindex.sgml,v 1.54 2007/01/09 02:14:10 tgl Exp $ -->
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<!-- $PostgreSQL: pgsql/doc/src/sgml/xindex.sgml,v 1.55 2007/01/20 23:13:01 tgl Exp $ -->
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<sect1 id="xindex">
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<title>Interfacing Extensions To Indexes</title>
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@ -287,20 +287,6 @@
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return type <type>boolean</type>, since they must appear at the top
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level of a <literal>WHERE</> clause to be used with an index.
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</para>
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<para>
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By the way, the <structfield>amorderstrategy</structfield> and
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<structfield>amdescorder</structfield> columns in <classname>pg_am</> tell
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whether the index method supports ordered scans. Zeroes mean it doesn't;
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if it does, <structfield>amorderstrategy</structfield> is the strategy
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number that corresponds to the default ordering operator, and
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<structfield>amdescorder</structfield> is the strategy number for the
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ordering operator of an index column that has the <literal>DESC</> option.
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For example, B-tree has <structfield>amorderstrategy</structfield> = 1,
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which is its <quote>less than</quote> strategy number, and
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<structfield>amdescorder</structfield> = 5, which is its
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<quote>greater than</quote> strategy number.
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</para>
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</sect2>
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<sect2 id="xindex-support">
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/commands/indexcmds.c,v 1.152 2007/01/09 02:14:11 tgl Exp $
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* $PostgreSQL: pgsql/src/backend/commands/indexcmds.c,v 1.153 2007/01/20 23:13:01 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -295,8 +295,7 @@ DefineIndex(RangeVar *heapRelation,
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errmsg("access method \"%s\" does not support multicolumn indexes",
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accessMethodName)));
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amcanorder = (accessMethodForm->amorderstrategy > 0);
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amcanorder = accessMethodForm->amcanorder;
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amoptions = accessMethodForm->amoptions;
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ReleaseSysCache(tuple);
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@ -9,7 +9,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/optimizer/util/plancat.c,v 1.131 2007/01/09 02:14:13 tgl Exp $
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* $PostgreSQL: pgsql/src/backend/optimizer/util/plancat.c,v 1.132 2007/01/20 23:13:01 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -190,8 +190,10 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
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/*
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* Fetch the ordering operators associated with the index, if any.
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* We expect that all ordering-capable indexes use btree's
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* strategy numbers for the ordering operators.
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*/
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if (indexRelation->rd_am->amorderstrategy > 0)
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if (indexRelation->rd_am->amcanorder)
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{
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int nstrat = indexRelation->rd_am->amstrategies;
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@ -203,17 +205,17 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
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if (opt & INDOPTION_DESC)
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{
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fwdstrat = indexRelation->rd_am->amdescorder;
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revstrat = indexRelation->rd_am->amorderstrategy;
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fwdstrat = BTGreaterStrategyNumber;
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revstrat = BTLessStrategyNumber;
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}
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else
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{
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fwdstrat = indexRelation->rd_am->amorderstrategy;
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revstrat = indexRelation->rd_am->amdescorder;
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fwdstrat = BTLessStrategyNumber;
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revstrat = BTGreaterStrategyNumber;
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}
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/*
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* Index AM must have a fixed set of strategies for it
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* to make sense to specify amorderstrategy, so we
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* to make sense to specify amcanorder, so we
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* need not allow the case amstrategies == 0.
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*/
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if (fwdstrat > 0)
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@ -9,7 +9,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.244 2007/01/20 01:08:42 neilc Exp $
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* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.245 2007/01/20 23:13:01 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -767,7 +767,7 @@ pg_get_indexdef_worker(Oid indexrelid, int colno, int prettyFlags)
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&buf);
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/* Add options if relevant */
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if (amrec->amorderstrategy > 0)
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if (amrec->amcanorder)
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{
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/* if it supports sort ordering, report DESC and NULLS opts */
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if (opt & INDOPTION_DESC)
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@ -37,7 +37,7 @@
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* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.374 2007/01/20 21:47:10 neilc Exp $
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* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.375 2007/01/20 23:13:01 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -53,6 +53,6 @@
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*/
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/* yyyymmddN */
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#define CATALOG_VERSION_NO 200701202
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#define CATALOG_VERSION_NO 200701203
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#endif
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@ -8,7 +8,7 @@
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* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/catalog/pg_am.h,v 1.49 2007/01/09 02:14:15 tgl Exp $
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* $PostgreSQL: pgsql/src/include/catalog/pg_am.h,v 1.50 2007/01/20 23:13:01 tgl Exp $
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*
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* NOTES
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* the genbki.sh script reads this file and generates .bki
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@ -45,12 +45,7 @@ CATALOG(pg_am,2601)
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* strategy assignments. */
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int2 amsupport; /* total number of support functions that this
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* AM uses */
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int2 amorderstrategy;/* if this AM has a sort order, the strategy
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* number of the default (ASC) sort operator.
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* Zero if AM is not ordered. */
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int2 amdescorder; /* if this AM has a sort order, the strategy
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* number of the DESC sort operator.
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* Zero if AM is not ordered. */
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bool amcanorder; /* does AM support ordered scan results? */
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bool amcanunique; /* does AM support UNIQUE indexes? */
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bool amcanmulticol; /* does AM support multi-column indexes? */
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bool amoptionalkey; /* can query omit key for the first column? */
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@ -83,47 +78,46 @@ typedef FormData_pg_am *Form_pg_am;
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* compiler constants for pg_am
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* ----------------
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*/
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#define Natts_pg_am 24
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#define Natts_pg_am 23
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#define Anum_pg_am_amname 1
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#define Anum_pg_am_amstrategies 2
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#define Anum_pg_am_amsupport 3
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#define Anum_pg_am_amorderstrategy 4
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#define Anum_pg_am_amdescorder 5
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#define Anum_pg_am_amcanunique 6
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#define Anum_pg_am_amcanmulticol 7
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#define Anum_pg_am_amoptionalkey 8
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#define Anum_pg_am_amindexnulls 9
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#define Anum_pg_am_amstorage 10
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#define Anum_pg_am_amclusterable 11
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#define Anum_pg_am_aminsert 12
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#define Anum_pg_am_ambeginscan 13
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#define Anum_pg_am_amgettuple 14
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#define Anum_pg_am_amgetmulti 15
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#define Anum_pg_am_amrescan 16
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#define Anum_pg_am_amendscan 17
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#define Anum_pg_am_ammarkpos 18
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#define Anum_pg_am_amrestrpos 19
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#define Anum_pg_am_ambuild 20
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#define Anum_pg_am_ambulkdelete 21
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#define Anum_pg_am_amvacuumcleanup 22
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#define Anum_pg_am_amcostestimate 23
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#define Anum_pg_am_amoptions 24
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#define Anum_pg_am_amcanorder 4
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#define Anum_pg_am_amcanunique 5
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#define Anum_pg_am_amcanmulticol 6
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#define Anum_pg_am_amoptionalkey 7
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#define Anum_pg_am_amindexnulls 8
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#define Anum_pg_am_amstorage 9
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#define Anum_pg_am_amclusterable 10
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#define Anum_pg_am_aminsert 11
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#define Anum_pg_am_ambeginscan 12
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#define Anum_pg_am_amgettuple 13
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#define Anum_pg_am_amgetmulti 14
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#define Anum_pg_am_amrescan 15
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#define Anum_pg_am_amendscan 16
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#define Anum_pg_am_ammarkpos 17
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#define Anum_pg_am_amrestrpos 18
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#define Anum_pg_am_ambuild 19
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#define Anum_pg_am_ambulkdelete 20
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#define Anum_pg_am_amvacuumcleanup 21
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#define Anum_pg_am_amcostestimate 22
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#define Anum_pg_am_amoptions 23
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/* ----------------
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* initial contents of pg_am
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* ----------------
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*/
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DATA(insert OID = 403 ( btree 5 1 1 5 t t t t f t btinsert btbeginscan btgettuple btgetmulti btrescan btendscan btmarkpos btrestrpos btbuild btbulkdelete btvacuumcleanup btcostestimate btoptions ));
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DATA(insert OID = 403 ( btree 5 1 t t t t t f t btinsert btbeginscan btgettuple btgetmulti btrescan btendscan btmarkpos btrestrpos btbuild btbulkdelete btvacuumcleanup btcostestimate btoptions ));
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DESCR("b-tree index access method");
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#define BTREE_AM_OID 403
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DATA(insert OID = 405 ( hash 1 1 0 0 f f f f f f hashinsert hashbeginscan hashgettuple hashgetmulti hashrescan hashendscan hashmarkpos hashrestrpos hashbuild hashbulkdelete hashvacuumcleanup hashcostestimate hashoptions ));
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DATA(insert OID = 405 ( hash 1 1 f f f f f f f hashinsert hashbeginscan hashgettuple hashgetmulti hashrescan hashendscan hashmarkpos hashrestrpos hashbuild hashbulkdelete hashvacuumcleanup hashcostestimate hashoptions ));
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DESCR("hash index access method");
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#define HASH_AM_OID 405
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DATA(insert OID = 783 ( gist 0 7 0 0 f t t t t t gistinsert gistbeginscan gistgettuple gistgetmulti gistrescan gistendscan gistmarkpos gistrestrpos gistbuild gistbulkdelete gistvacuumcleanup gistcostestimate gistoptions ));
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DATA(insert OID = 783 ( gist 0 7 f f t t t t t gistinsert gistbeginscan gistgettuple gistgetmulti gistrescan gistendscan gistmarkpos gistrestrpos gistbuild gistbulkdelete gistvacuumcleanup gistcostestimate gistoptions ));
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DESCR("GiST index access method");
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#define GIST_AM_OID 783
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DATA(insert OID = 2742 ( gin 0 4 0 0 f f f f t f gininsert ginbeginscan gingettuple gingetmulti ginrescan ginendscan ginmarkpos ginrestrpos ginbuild ginbulkdelete ginvacuumcleanup gincostestimate ginoptions ));
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DATA(insert OID = 2742 ( gin 0 4 f f f f f t f gininsert ginbeginscan gingettuple gingetmulti ginrescan ginendscan ginmarkpos ginrestrpos ginbuild ginbulkdelete ginvacuumcleanup gincostestimate ginoptions ));
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DESCR("GIN index access method");
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#define GIN_AM_OID 2742
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