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Diffstat (limited to 'src/backend/parser/parse_clause.c')
-rw-r--r--src/backend/parser/parse_clause.c190
1 files changed, 134 insertions, 56 deletions
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index e90e1d68e3a..4e490b23b4e 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -18,8 +18,8 @@
#include "miscadmin.h"
#include "access/heapam.h"
+#include "access/tsmapi.h"
#include "catalog/catalog.h"
-#include "access/htup_details.h"
#include "catalog/heap.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_type.h"
@@ -43,7 +43,7 @@
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
-#include "utils/syscache.h"
+
/* Convenience macro for the most common makeNamespaceItem() case */
#define makeDefaultNSItem(rte) makeNamespaceItem(rte, true, true, false, true)
@@ -63,6 +63,8 @@ static RangeTblEntry *transformRangeSubselect(ParseState *pstate,
RangeSubselect *r);
static RangeTblEntry *transformRangeFunction(ParseState *pstate,
RangeFunction *r);
+static TableSampleClause *transformRangeTableSample(ParseState *pstate,
+ RangeTableSample *rts);
static Node *transformFromClauseItem(ParseState *pstate, Node *n,
RangeTblEntry **top_rte, int *top_rti,
List **namespace);
@@ -423,40 +425,6 @@ transformJoinOnClause(ParseState *pstate, JoinExpr *j, List *namespace)
return result;
}
-static RangeTblEntry *
-transformTableSampleEntry(ParseState *pstate, RangeTableSample *rv)
-{
- RangeTblEntry *rte = NULL;
- CommonTableExpr *cte = NULL;
- TableSampleClause *tablesample = NULL;
-
- /* if relation has an unqualified name, it might be a CTE reference */
- if (!rv->relation->schemaname)
- {
- Index levelsup;
-
- cte = scanNameSpaceForCTE(pstate, rv->relation->relname, &levelsup);
- }
-
- /* We first need to build a range table entry */
- if (!cte)
- rte = transformTableEntry(pstate, rv->relation);
-
- if (!rte ||
- (rte->relkind != RELKIND_RELATION &&
- rte->relkind != RELKIND_MATVIEW))
- ereport(ERROR,
- (errcode(ERRCODE_SYNTAX_ERROR),
- errmsg("TABLESAMPLE clause can only be used on tables and materialized views"),
- parser_errposition(pstate, rv->relation->location)));
-
- tablesample = ParseTableSample(pstate, rv->method, rv->repeatable,
- rv->args, rv->relation->location);
- rte->tablesample = tablesample;
-
- return rte;
-}
-
/*
* transformTableEntry --- transform a RangeVar (simple relation reference)
*/
@@ -748,6 +716,109 @@ transformRangeFunction(ParseState *pstate, RangeFunction *r)
return rte;
}
+/*
+ * transformRangeTableSample --- transform a TABLESAMPLE clause
+ *
+ * Caller has already transformed rts->relation, we just have to validate
+ * the remaining fields and create a TableSampleClause node.
+ */
+static TableSampleClause *
+transformRangeTableSample(ParseState *pstate, RangeTableSample *rts)
+{
+ TableSampleClause *tablesample;
+ Oid handlerOid;
+ Oid funcargtypes[1];
+ TsmRoutine *tsm;
+ List *fargs;
+ ListCell *larg,
+ *ltyp;
+
+ /*
+ * To validate the sample method name, look up the handler function, which
+ * has the same name, one dummy INTERNAL argument, and a result type of
+ * tsm_handler. (Note: tablesample method names are not schema-qualified
+ * in the SQL standard; but since they are just functions to us, we allow
+ * schema qualification to resolve any potential ambiguity.)
+ */
+ funcargtypes[0] = INTERNALOID;
+
+ handlerOid = LookupFuncName(rts->method, 1, funcargtypes, true);
+
+ /* we want error to complain about no-such-method, not no-such-function */
+ if (!OidIsValid(handlerOid))
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_OBJECT),
+ errmsg("tablesample method %s does not exist",
+ NameListToString(rts->method)),
+ parser_errposition(pstate, rts->location)));
+
+ /* check that handler has correct return type */
+ if (get_func_rettype(handlerOid) != TSM_HANDLEROID)
+ ereport(ERROR,
+ (errcode(ERRCODE_WRONG_OBJECT_TYPE),
+ errmsg("function %s must return type \"tsm_handler\"",
+ NameListToString(rts->method)),
+ parser_errposition(pstate, rts->location)));
+
+ /* OK, run the handler to get TsmRoutine, for argument type info */
+ tsm = GetTsmRoutine(handlerOid);
+
+ tablesample = makeNode(TableSampleClause);
+ tablesample->tsmhandler = handlerOid;
+
+ /* check user provided the expected number of arguments */
+ if (list_length(rts->args) != list_length(tsm->parameterTypes))
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_TABLESAMPLE_ARGUMENT),
+ errmsg_plural("tablesample method %s requires %d argument, not %d",
+ "tablesample method %s requires %d arguments, not %d",
+ list_length(tsm->parameterTypes),
+ NameListToString(rts->method),
+ list_length(tsm->parameterTypes),
+ list_length(rts->args)),
+ parser_errposition(pstate, rts->location)));
+
+ /*
+ * Transform the arguments, typecasting them as needed. Note we must also
+ * assign collations now, because assign_query_collations() doesn't
+ * examine any substructure of RTEs.
+ */
+ fargs = NIL;
+ forboth(larg, rts->args, ltyp, tsm->parameterTypes)
+ {
+ Node *arg = (Node *) lfirst(larg);
+ Oid argtype = lfirst_oid(ltyp);
+
+ arg = transformExpr(pstate, arg, EXPR_KIND_FROM_FUNCTION);
+ arg = coerce_to_specific_type(pstate, arg, argtype, "TABLESAMPLE");
+ assign_expr_collations(pstate, arg);
+ fargs = lappend(fargs, arg);
+ }
+ tablesample->args = fargs;
+
+ /* Process REPEATABLE (seed) */
+ if (rts->repeatable != NULL)
+ {
+ Node *arg;
+
+ if (!tsm->repeatable_across_queries)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("tablesample method %s does not support REPEATABLE",
+ NameListToString(rts->method)),
+ parser_errposition(pstate, rts->location)));
+
+ arg = transformExpr(pstate, rts->repeatable, EXPR_KIND_FROM_FUNCTION);
+ arg = coerce_to_specific_type(pstate, arg, FLOAT8OID, "REPEATABLE");
+ assign_expr_collations(pstate, arg);
+ tablesample->repeatable = (Expr *) arg;
+ }
+ else
+ tablesample->repeatable = NULL;
+
+ return tablesample;
+}
+
/*
* transformFromClauseItem -
@@ -844,6 +915,33 @@ transformFromClauseItem(ParseState *pstate, Node *n,
rtr->rtindex = rtindex;
return (Node *) rtr;
}
+ else if (IsA(n, RangeTableSample))
+ {
+ /* TABLESAMPLE clause (wrapping some other valid FROM node) */
+ RangeTableSample *rts = (RangeTableSample *) n;
+ Node *rel;
+ RangeTblRef *rtr;
+ RangeTblEntry *rte;
+
+ /* Recursively transform the contained relation */
+ rel = transformFromClauseItem(pstate, rts->relation,
+ top_rte, top_rti, namespace);
+ /* Currently, grammar could only return a RangeVar as contained rel */
+ Assert(IsA(rel, RangeTblRef));
+ rtr = (RangeTblRef *) rel;
+ rte = rt_fetch(rtr->rtindex, pstate->p_rtable);
+ /* We only support this on plain relations and matviews */
+ if (rte->relkind != RELKIND_RELATION &&
+ rte->relkind != RELKIND_MATVIEW)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("TABLESAMPLE clause can only be applied to tables and materialized views"),
+ parser_errposition(pstate, exprLocation(rts->relation))));
+
+ /* Transform TABLESAMPLE details and attach to the RTE */
+ rte->tablesample = transformRangeTableSample(pstate, rts);
+ return (Node *) rtr;
+ }
else if (IsA(n, JoinExpr))
{
/* A newfangled join expression */
@@ -1165,26 +1263,6 @@ transformFromClauseItem(ParseState *pstate, Node *n,
return (Node *) j;
}
- else if (IsA(n, RangeTableSample))
- {
- /* Tablesample reference */
- RangeTableSample *rv = (RangeTableSample *) n;
- RangeTblRef *rtr;
- RangeTblEntry *rte = NULL;
- int rtindex;
-
- rte = transformTableSampleEntry(pstate, rv);
-
- /* assume new rte is at end */
- rtindex = list_length(pstate->p_rtable);
- Assert(rte == rt_fetch(rtindex, pstate->p_rtable));
- *top_rte = rte;
- *top_rti = rtindex;
- *namespace = list_make1(makeDefaultNSItem(rte));
- rtr = makeNode(RangeTblRef);
- rtr->rtindex = rtindex;
- return (Node *) rtr;
- }
else
elog(ERROR, "unrecognized node type: %d", (int) nodeTag(n));
return NULL; /* can't get here, keep compiler quiet */
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-23 12:45:16 +0000