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Modify pg_dump to dump foreign-key constraints as constraints, not as
sets of triggers. Also modify psql \d command to show foreign key constraints as such and hide the triggers. pg_get_constraintdef() function added to backend to support these. From Rod Taylor, code review and some editorialization by Tom Lane.
This commit is contained in:
Tom Lane
@@ -3,7 +3,7 @@
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* back to source text
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.115 2002/08/16 20:55:09 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.116 2002/08/16 23:01:19 tgl Exp $
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*
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* This software is copyrighted by Jan Wieck - Hamburg.
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*
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@@ -40,10 +40,14 @@
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#include <unistd.h>
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#include <fcntl.h>
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#include "access/genam.h"
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#include "catalog/catname.h"
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#include "catalog/heap.h"
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#include "catalog/index.h"
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#include "catalog/indexing.h"
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#include "catalog/namespace.h"
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#include "catalog/pg_cast.h"
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#include "catalog/pg_constraint.h"
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#include "catalog/pg_index.h"
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#include "catalog/pg_opclass.h"
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#include "catalog/pg_operator.h"
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@@ -60,6 +64,8 @@
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#include "parser/parsetree.h"
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#include "rewrite/rewriteManip.h"
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#include "rewrite/rewriteSupport.h"
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#include "utils/array.h"
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#include "utils/fmgroids.h"
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#include "utils/lsyscache.h"
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@@ -116,6 +122,8 @@ static char *query_getviewrule = "SELECT * FROM pg_catalog.pg_rewrite WHERE ev_c
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* ----------
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*/
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static text *pg_do_getviewdef(Oid viewoid);
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static void decompile_column_index_array(Datum column_index_array, Oid relId,
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StringInfo buf);
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static void make_ruledef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc);
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static void make_viewdef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc);
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static void get_query_def(Query *query, StringInfo buf, List *parentnamespace,
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@@ -528,6 +536,214 @@ pg_get_indexdef(PG_FUNCTION_ARGS)
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}
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/*
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* pg_get_constraintdef
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*
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* Returns the definition for the constraint, ie, everything that needs to
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* appear after "ALTER TABLE ... ADD CONSTRAINT <constraintname>".
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*
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* XXX The present implementation only works for foreign-key constraints, but
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* it could and should handle anything pg_constraint stores.
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*/
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Datum
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pg_get_constraintdef(PG_FUNCTION_ARGS)
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{
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Oid constraintId = PG_GETARG_OID(0);
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text *result;
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StringInfoData buf;
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int len;
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Relation conDesc;
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SysScanDesc conscan;
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ScanKeyData skey[1];
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HeapTuple tup;
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Form_pg_constraint conForm;
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/*
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* Fetch the pg_constraint row. There's no syscache for pg_constraint
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* so we must do it the hard way.
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*/
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conDesc = heap_openr(ConstraintRelationName, AccessShareLock);
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ScanKeyEntryInitialize(&skey[0], 0x0,
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ObjectIdAttributeNumber, F_OIDEQ,
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ObjectIdGetDatum(constraintId));
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conscan = systable_beginscan(conDesc, ConstraintOidIndex, true,
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SnapshotNow, 1, skey);
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tup = systable_getnext(conscan);
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if (!HeapTupleIsValid(tup))
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elog(ERROR, "Failed to find constraint with OID %u", constraintId);
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conForm = (Form_pg_constraint) GETSTRUCT(tup);
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initStringInfo(&buf);
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switch (conForm->contype)
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{
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case CONSTRAINT_FOREIGN:
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{
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Datum val;
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bool isnull;
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const char *string;
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/* Start off the constraint definition */
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appendStringInfo(&buf, "FOREIGN KEY (");
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/* Fetch and build referencing-column list */
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val = heap_getattr(tup, Anum_pg_constraint_conkey,
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RelationGetDescr(conDesc), &isnull);
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if (isnull)
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elog(ERROR, "pg_get_constraintdef: Null conkey for constraint %u",
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constraintId);
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decompile_column_index_array(val, conForm->conrelid, &buf);
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/* add foreign relation name */
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appendStringInfo(&buf, ") REFERENCES %s(",
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generate_relation_name(conForm->confrelid));
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/* Fetch and build referenced-column list */
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val = heap_getattr(tup, Anum_pg_constraint_confkey,
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RelationGetDescr(conDesc), &isnull);
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if (isnull)
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elog(ERROR, "pg_get_constraintdef: Null confkey for constraint %u",
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constraintId);
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decompile_column_index_array(val, conForm->confrelid, &buf);
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appendStringInfo(&buf, ")");
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/* Add match type */
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switch (conForm->confmatchtype)
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{
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case FKCONSTR_MATCH_FULL:
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string = " MATCH FULL";
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break;
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case FKCONSTR_MATCH_PARTIAL:
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string = " MATCH PARTIAL";
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break;
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case FKCONSTR_MATCH_UNSPECIFIED:
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string = "";
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break;
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default:
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elog(ERROR, "pg_get_constraintdef: Unknown confmatchtype '%c' for constraint %u",
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conForm->confmatchtype, constraintId);
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string = ""; /* keep compiler quiet */
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break;
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}
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appendStringInfo(&buf, "%s", string);
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/* Add ON UPDATE and ON DELETE clauses */
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switch (conForm->confupdtype)
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{
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case FKCONSTR_ACTION_NOACTION:
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string = "NO ACTION";
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break;
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case FKCONSTR_ACTION_RESTRICT:
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string = "RESTRICT";
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break;
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case FKCONSTR_ACTION_CASCADE:
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string = "CASCADE";
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break;
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case FKCONSTR_ACTION_SETNULL:
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string = "SET NULL";
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break;
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case FKCONSTR_ACTION_SETDEFAULT:
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string = "SET DEFAULT";
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break;
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default:
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elog(ERROR, "pg_get_constraintdef: Unknown confupdtype '%c' for constraint %u",
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conForm->confupdtype, constraintId);
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string = ""; /* keep compiler quiet */
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break;
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}
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appendStringInfo(&buf, " ON UPDATE %s", string);
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switch (conForm->confdeltype)
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{
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case FKCONSTR_ACTION_NOACTION:
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string = "NO ACTION";
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break;
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case FKCONSTR_ACTION_RESTRICT:
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string = "RESTRICT";
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break;
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case FKCONSTR_ACTION_CASCADE:
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string = "CASCADE";
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break;
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case FKCONSTR_ACTION_SETNULL:
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string = "SET NULL";
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break;
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case FKCONSTR_ACTION_SETDEFAULT:
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string = "SET DEFAULT";
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break;
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default:
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elog(ERROR, "pg_get_constraintdef: Unknown confdeltype '%c' for constraint %u",
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conForm->confdeltype, constraintId);
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string = ""; /* keep compiler quiet */
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break;
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}
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appendStringInfo(&buf, " ON DELETE %s", string);
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break;
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}
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/*
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* XXX Add more code here for other contypes
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*/
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default:
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elog(ERROR, "pg_get_constraintdef: unsupported constraint type '%c'",
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conForm->contype);
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break;
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}
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/* Record the results */
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len = buf.len + VARHDRSZ;
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result = (text *) palloc(len);
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VARATT_SIZEP(result) = len;
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memcpy(VARDATA(result), buf.data, buf.len);
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/* Cleanup */
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pfree(buf.data);
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systable_endscan(conscan);
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heap_close(conDesc, AccessShareLock);
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PG_RETURN_TEXT_P(result);
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}
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/*
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* Convert an int16[] Datum into a comma-separated list of column names
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* for the indicated relation; append the list to buf.
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*/
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static void
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decompile_column_index_array(Datum column_index_array, Oid relId,
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StringInfo buf)
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{
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Datum *keys;
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int nKeys;
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int j;
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/* Extract data from array of int16 */
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deconstruct_array(DatumGetArrayTypeP(column_index_array),
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true, 2, 's',
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&keys, &nKeys);
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for (j = 0; j < nKeys; j++)
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{
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char *colName;
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colName = get_attname(relId, DatumGetInt16(keys[j]));
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if (j == 0)
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appendStringInfo(buf, "%s",
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quote_identifier(colName));
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else
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appendStringInfo(buf, ", %s",
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quote_identifier(colName));
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}
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}
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/* ----------
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* get_expr - Decompile an expression tree
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*
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