From 261f954e7a5861e1706a1e77f5d44c57335d37a6 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 11 Jul 2014 19:12:45 -0400 Subject: [PATCH] Fix bug with whole-row references to append subplans. ExecEvalWholeRowVar incorrectly supposed that it could "bless" the source TupleTableSlot just once per query. But if the input is coming from an Append (or, perhaps, other cases?) more than one slot might be returned over the query run. This led to "record type has not been registered" errors when a composite datum was extracted from a non-blessed slot. This bug has been there a long time; I guess it escaped notice because when dealing with subqueries the planner tends to expand whole-row Vars into RowExprs, which don't have the same problem. It is possible to trigger the problem in all active branches, though, as illustrated by the added regression test. --- src/backend/executor/execQual.c | 33 ++++++++++++++----------- src/test/regress/expected/subselect.out | 18 ++++++++++++++ src/test/regress/sql/subselect.sql | 10 ++++++++ 3 files changed, 47 insertions(+), 14 deletions(-) diff --git a/src/backend/executor/execQual.c b/src/backend/executor/execQual.c index b1e0cee156..d593453abf 100644 --- a/src/backend/executor/execQual.c +++ b/src/backend/executor/execQual.c @@ -710,7 +710,6 @@ ExecEvalWholeRowVar(WholeRowVarExprState *wrvstate, ExprContext *econtext, { Var *variable = (Var *) wrvstate->xprstate.expr; TupleTableSlot *slot; - TupleDesc slot_tupdesc; bool needslow = false; if (isDone) @@ -802,25 +801,14 @@ ExecEvalWholeRowVar(WholeRowVarExprState *wrvstate, ExprContext *econtext, if (wrvstate->wrv_junkFilter != NULL) slot = ExecFilterJunk(wrvstate->wrv_junkFilter, slot); - slot_tupdesc = slot->tts_tupleDescriptor; - /* - * If it's a RECORD Var, we'll use the slot's type ID info. It's likely - * that the slot's type is also RECORD; if so, make sure it's been - * "blessed", so that the Datum can be interpreted later. - * * If the Var identifies a named composite type, we must check that the * actual tuple type is compatible with it. */ - if (variable->vartype == RECORDOID) - { - if (slot_tupdesc->tdtypeid == RECORDOID && - slot_tupdesc->tdtypmod < 0) - assign_record_type_typmod(slot_tupdesc); - } - else + if (variable->vartype != RECORDOID) { TupleDesc var_tupdesc; + TupleDesc slot_tupdesc; int i; /* @@ -837,6 +825,8 @@ ExecEvalWholeRowVar(WholeRowVarExprState *wrvstate, ExprContext *econtext, */ var_tupdesc = lookup_rowtype_tupdesc(variable->vartype, -1); + slot_tupdesc = slot->tts_tupleDescriptor; + if (var_tupdesc->natts != slot_tupdesc->natts) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), @@ -894,6 +884,7 @@ ExecEvalWholeRowFast(WholeRowVarExprState *wrvstate, ExprContext *econtext, { Var *variable = (Var *) wrvstate->xprstate.expr; TupleTableSlot *slot; + TupleDesc slot_tupdesc; HeapTupleHeader dtuple; if (isDone) @@ -923,6 +914,20 @@ ExecEvalWholeRowFast(WholeRowVarExprState *wrvstate, ExprContext *econtext, if (wrvstate->wrv_junkFilter != NULL) slot = ExecFilterJunk(wrvstate->wrv_junkFilter, slot); + /* + * If it's a RECORD Var, we'll use the slot's type ID info. It's likely + * that the slot's type is also RECORD; if so, make sure it's been + * "blessed", so that the Datum can be interpreted later. (Note: we must + * do this here, not in ExecEvalWholeRowVar, because some plan trees may + * return different slots at different times. We have to be ready to + * bless additional slots during the run.) + */ + slot_tupdesc = slot->tts_tupleDescriptor; + if (variable->vartype == RECORDOID && + slot_tupdesc->tdtypeid == RECORDOID && + slot_tupdesc->tdtypmod < 0) + assign_record_type_typmod(slot_tupdesc); + /* * Copy the slot tuple and make sure any toasted fields get detoasted. */ diff --git a/src/test/regress/expected/subselect.out b/src/test/regress/expected/subselect.out index 543709ac3f..d437cc66d5 100644 --- a/src/test/regress/expected/subselect.out +++ b/src/test/regress/expected/subselect.out @@ -775,3 +775,21 @@ select * from int4_tbl o where (f1, f1) in 0 (1 row) +-- +-- check for over-optimization of whole-row Var referencing an Append plan +-- +select (select q from + (select 1,2,3 where f1 > 0 + union all + select 4,5,6.0 where f1 <= 0 + ) q ) +from int4_tbl; + q +----------- + (4,5,6.0) + (1,2,3) + (4,5,6.0) + (1,2,3) + (4,5,6.0) +(5 rows) + diff --git a/src/test/regress/sql/subselect.sql b/src/test/regress/sql/subselect.sql index 1975902726..55ff70d47c 100644 --- a/src/test/regress/sql/subselect.sql +++ b/src/test/regress/sql/subselect.sql @@ -431,3 +431,13 @@ select * from int4_tbl o where (f1, f1) in (select f1, generate_series(1,2) / 10 g from int4_tbl i group by f1); select * from int4_tbl o where (f1, f1) in (select f1, generate_series(1,2) / 10 g from int4_tbl i group by f1); + +-- +-- check for over-optimization of whole-row Var referencing an Append plan +-- +select (select q from + (select 1,2,3 where f1 > 0 + union all + select 4,5,6.0 where f1 <= 0 + ) q ) +from int4_tbl; -- 2.40.0