2017-04-01 06:17:18 +02:00
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/*-------------------------------------------------------------------------
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*
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* nodeNamedtuplestorescan.c
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* routines to handle NamedTuplestoreScan nodes.
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*
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2020-01-01 18:21:45 +01:00
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* Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
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2017-04-01 06:17:18 +02:00
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* src/backend/executor/nodeNamedtuplestorescan.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "executor/execdebug.h"
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#include "executor/nodeNamedtuplestorescan.h"
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#include "miscadmin.h"
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#include "utils/queryenvironment.h"
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static TupleTableSlot *NamedTuplestoreScanNext(NamedTuplestoreScanState *node);
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/* ----------------------------------------------------------------
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* NamedTuplestoreScanNext
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*
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* This is a workhorse for ExecNamedTuplestoreScan
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* ----------------------------------------------------------------
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*/
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static TupleTableSlot *
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NamedTuplestoreScanNext(NamedTuplestoreScanState *node)
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{
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TupleTableSlot *slot;
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/* We intentionally do not support backward scan. */
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Assert(ScanDirectionIsForward(node->ss.ps.state->es_direction));
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/*
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* Get the next tuple from tuplestore. Return NULL if no more tuples.
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*/
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slot = node->ss.ss_ScanTupleSlot;
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2018-02-27 21:56:51 +01:00
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tuplestore_select_read_pointer(node->relation, node->readptr);
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2017-04-01 06:17:18 +02:00
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(void) tuplestore_gettupleslot(node->relation, true, false, slot);
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return slot;
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}
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/*
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* NamedTuplestoreScanRecheck -- access method routine to recheck a tuple in
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* EvalPlanQual
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*/
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static bool
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NamedTuplestoreScanRecheck(NamedTuplestoreScanState *node, TupleTableSlot *slot)
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{
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/* nothing to check */
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return true;
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}
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/* ----------------------------------------------------------------
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* ExecNamedTuplestoreScan(node)
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*
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* Scans the CTE sequentially and returns the next qualifying tuple.
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* We call the ExecScan() routine and pass it the appropriate
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* access method functions.
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* ----------------------------------------------------------------
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*/
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2017-07-17 09:33:49 +02:00
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static TupleTableSlot *
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ExecNamedTuplestoreScan(PlanState *pstate)
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2017-04-01 06:17:18 +02:00
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{
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2017-07-17 09:33:49 +02:00
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NamedTuplestoreScanState *node = castNode(NamedTuplestoreScanState, pstate);
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2017-04-01 06:17:18 +02:00
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return ExecScan(&node->ss,
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(ExecScanAccessMtd) NamedTuplestoreScanNext,
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(ExecScanRecheckMtd) NamedTuplestoreScanRecheck);
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}
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/* ----------------------------------------------------------------
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* ExecInitNamedTuplestoreScan
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* ----------------------------------------------------------------
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*/
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NamedTuplestoreScanState *
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ExecInitNamedTuplestoreScan(NamedTuplestoreScan *node, EState *estate, int eflags)
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{
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NamedTuplestoreScanState *scanstate;
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EphemeralNamedRelation enr;
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/* check for unsupported flags */
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Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
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/*
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* NamedTuplestoreScan should not have any children.
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*/
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Assert(outerPlan(node) == NULL);
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Assert(innerPlan(node) == NULL);
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/*
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* create new NamedTuplestoreScanState for node
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*/
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scanstate = makeNode(NamedTuplestoreScanState);
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scanstate->ss.ps.plan = (Plan *) node;
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scanstate->ss.ps.state = estate;
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2017-07-17 09:33:49 +02:00
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scanstate->ss.ps.ExecProcNode = ExecNamedTuplestoreScan;
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2017-04-01 06:17:18 +02:00
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enr = get_ENR(estate->es_queryEnv, node->enrname);
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if (!enr)
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elog(ERROR, "executor could not find named tuplestore \"%s\"",
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node->enrname);
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Assert(enr->reldata);
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scanstate->relation = (Tuplestorestate *) enr->reldata;
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scanstate->tupdesc = ENRMetadataGetTupDesc(&(enr->md));
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scanstate->readptr =
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2017-05-10 05:13:21 +02:00
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tuplestore_alloc_read_pointer(scanstate->relation, EXEC_FLAG_REWIND);
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2017-04-01 06:17:18 +02:00
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/*
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* The new read pointer copies its position from read pointer 0, which
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* could be anywhere, so explicitly rewind it.
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*/
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2018-02-27 21:56:51 +01:00
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tuplestore_select_read_pointer(scanstate->relation, scanstate->readptr);
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2017-04-01 06:17:18 +02:00
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tuplestore_rescan(scanstate->relation);
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/*
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* XXX: Should we add a function to free that read pointer when done?
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2017-05-17 02:36:35 +02:00
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*
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2017-04-01 06:17:18 +02:00
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* This was attempted, but it did not improve performance or memory usage
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* in any tested cases.
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*/
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/*
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* Miscellaneous initialization
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*
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* create expression context for node
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*/
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ExecAssignExprContext(estate, &scanstate->ss.ps);
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/*
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Don't require return slots for nodes without projection.
In a lot of nodes the return slot is not required. That can either be
because the node doesn't do any projection (say an Append node), or
because the node does perform projections but the projection is
optimized away because the projection would yield an identical row.
Slots aren't that small, especially for wide rows, so it's worthwhile
to avoid creating them. It's not possible to just skip creating the
slot - it's currently used to determine the tuple descriptor returned
by ExecGetResultType(). So separate the determination of the result
type from the slot creation. The work previously done internally
ExecInitResultTupleSlotTL() can now also be done separately with
ExecInitResultTypeTL() and ExecInitResultSlot(). That way nodes that
aren't guaranteed to need a result slot, can use
ExecInitResultTypeTL() to determine the result type of the node, and
ExecAssignScanProjectionInfo() (via
ExecConditionalAssignProjectionInfo()) determines that a result slot
is needed, it is created with ExecInitResultSlot().
Besides the advantage of avoiding to create slots that then are
unused, this is necessary preparation for later patches around tuple
table slot abstraction. In particular separating the return descriptor
and slot is a prerequisite to allow JITing of tuple deforming with
knowledge of the underlying tuple format, and to avoid unnecessarily
creating JITed tuple deforming for virtual slots.
This commit removes a redundant argument from
ExecInitResultTupleSlotTL(). While this commit touches a lot of the
relevant lines anyway, it'd normally still not worthwhile to cause
breakage, except that aforementioned later commits will touch *all*
ExecInitResultTupleSlotTL() callers anyway (but fits worse
thematically).
Author: Andres Freund
Discussion: https://postgr.es/m/20181105210039.hh4vvi4vwoq5ba2q@alap3.anarazel.de
2018-11-10 02:19:39 +01:00
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* The scan tuple type is specified for the tuplestore.
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2017-04-01 06:17:18 +02:00
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*/
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Introduce notion of different types of slots (without implementing them).
Upcoming work intends to allow pluggable ways to introduce new ways of
storing table data. Accessing those table access methods from the
executor requires TupleTableSlots to be carry tuples in the native
format of such storage methods; otherwise there'll be a significant
conversion overhead.
Different access methods will require different data to store tuples
efficiently (just like virtual, minimal, heap already require fields
in TupleTableSlot). To allow that without requiring additional pointer
indirections, we want to have different structs (embedding
TupleTableSlot) for different types of slots. Thus different types of
slots are needed, which requires adapting creators of slots.
The slot that most efficiently can represent a type of tuple in an
executor node will often depend on the type of slot a child node
uses. Therefore we need to track the type of slot is returned by
nodes, so parent slots can create slots based on that.
Relatedly, JIT compilation of tuple deforming needs to know which type
of slot a certain expression refers to, so it can create an
appropriate deforming function for the type of tuple in the slot.
But not all nodes will only return one type of slot, e.g. an append
node will potentially return different types of slots for each of its
subplans.
Therefore add function that allows to query the type of a node's
result slot, and whether it'll always be the same type (whether it's
fixed). This can be queried using ExecGetResultSlotOps().
The scan, result, inner, outer type of slots are automatically
inferred from ExecInitScanTupleSlot(), ExecInitResultSlot(),
left/right subtrees respectively. If that's not correct for a node,
that can be overwritten using new fields in PlanState.
This commit does not introduce the actually abstracted implementation
of different kind of TupleTableSlots, that will be left for a followup
commit. The different types of slots introduced will, for now, still
use the same backing implementation.
While this already partially invalidates the big comment in
tuptable.h, it seems to make more sense to update it later, when the
different TupleTableSlot implementations actually exist.
Author: Ashutosh Bapat and Andres Freund, with changes by Amit Khandekar
Discussion: https://postgr.es/m/20181105210039.hh4vvi4vwoq5ba2q@alap3.anarazel.de
2018-11-16 07:00:30 +01:00
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ExecInitScanTupleSlot(estate, &scanstate->ss, scanstate->tupdesc,
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&TTSOpsMinimalTuple);
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2017-04-01 06:17:18 +02:00
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/*
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Don't require return slots for nodes without projection.
In a lot of nodes the return slot is not required. That can either be
because the node doesn't do any projection (say an Append node), or
because the node does perform projections but the projection is
optimized away because the projection would yield an identical row.
Slots aren't that small, especially for wide rows, so it's worthwhile
to avoid creating them. It's not possible to just skip creating the
slot - it's currently used to determine the tuple descriptor returned
by ExecGetResultType(). So separate the determination of the result
type from the slot creation. The work previously done internally
ExecInitResultTupleSlotTL() can now also be done separately with
ExecInitResultTypeTL() and ExecInitResultSlot(). That way nodes that
aren't guaranteed to need a result slot, can use
ExecInitResultTypeTL() to determine the result type of the node, and
ExecAssignScanProjectionInfo() (via
ExecConditionalAssignProjectionInfo()) determines that a result slot
is needed, it is created with ExecInitResultSlot().
Besides the advantage of avoiding to create slots that then are
unused, this is necessary preparation for later patches around tuple
table slot abstraction. In particular separating the return descriptor
and slot is a prerequisite to allow JITing of tuple deforming with
knowledge of the underlying tuple format, and to avoid unnecessarily
creating JITed tuple deforming for virtual slots.
This commit removes a redundant argument from
ExecInitResultTupleSlotTL(). While this commit touches a lot of the
relevant lines anyway, it'd normally still not worthwhile to cause
breakage, except that aforementioned later commits will touch *all*
ExecInitResultTupleSlotTL() callers anyway (but fits worse
thematically).
Author: Andres Freund
Discussion: https://postgr.es/m/20181105210039.hh4vvi4vwoq5ba2q@alap3.anarazel.de
2018-11-10 02:19:39 +01:00
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* Initialize result type and projection.
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2017-04-01 06:17:18 +02:00
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*/
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Don't require return slots for nodes without projection.
In a lot of nodes the return slot is not required. That can either be
because the node doesn't do any projection (say an Append node), or
because the node does perform projections but the projection is
optimized away because the projection would yield an identical row.
Slots aren't that small, especially for wide rows, so it's worthwhile
to avoid creating them. It's not possible to just skip creating the
slot - it's currently used to determine the tuple descriptor returned
by ExecGetResultType(). So separate the determination of the result
type from the slot creation. The work previously done internally
ExecInitResultTupleSlotTL() can now also be done separately with
ExecInitResultTypeTL() and ExecInitResultSlot(). That way nodes that
aren't guaranteed to need a result slot, can use
ExecInitResultTypeTL() to determine the result type of the node, and
ExecAssignScanProjectionInfo() (via
ExecConditionalAssignProjectionInfo()) determines that a result slot
is needed, it is created with ExecInitResultSlot().
Besides the advantage of avoiding to create slots that then are
unused, this is necessary preparation for later patches around tuple
table slot abstraction. In particular separating the return descriptor
and slot is a prerequisite to allow JITing of tuple deforming with
knowledge of the underlying tuple format, and to avoid unnecessarily
creating JITed tuple deforming for virtual slots.
This commit removes a redundant argument from
ExecInitResultTupleSlotTL(). While this commit touches a lot of the
relevant lines anyway, it'd normally still not worthwhile to cause
breakage, except that aforementioned later commits will touch *all*
ExecInitResultTupleSlotTL() callers anyway (but fits worse
thematically).
Author: Andres Freund
Discussion: https://postgr.es/m/20181105210039.hh4vvi4vwoq5ba2q@alap3.anarazel.de
2018-11-10 02:19:39 +01:00
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ExecInitResultTypeTL(&scanstate->ss.ps);
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ExecAssignScanProjectionInfo(&scanstate->ss);
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2017-04-01 06:17:18 +02:00
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/*
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Don't require return slots for nodes without projection.
In a lot of nodes the return slot is not required. That can either be
because the node doesn't do any projection (say an Append node), or
because the node does perform projections but the projection is
optimized away because the projection would yield an identical row.
Slots aren't that small, especially for wide rows, so it's worthwhile
to avoid creating them. It's not possible to just skip creating the
slot - it's currently used to determine the tuple descriptor returned
by ExecGetResultType(). So separate the determination of the result
type from the slot creation. The work previously done internally
ExecInitResultTupleSlotTL() can now also be done separately with
ExecInitResultTypeTL() and ExecInitResultSlot(). That way nodes that
aren't guaranteed to need a result slot, can use
ExecInitResultTypeTL() to determine the result type of the node, and
ExecAssignScanProjectionInfo() (via
ExecConditionalAssignProjectionInfo()) determines that a result slot
is needed, it is created with ExecInitResultSlot().
Besides the advantage of avoiding to create slots that then are
unused, this is necessary preparation for later patches around tuple
table slot abstraction. In particular separating the return descriptor
and slot is a prerequisite to allow JITing of tuple deforming with
knowledge of the underlying tuple format, and to avoid unnecessarily
creating JITed tuple deforming for virtual slots.
This commit removes a redundant argument from
ExecInitResultTupleSlotTL(). While this commit touches a lot of the
relevant lines anyway, it'd normally still not worthwhile to cause
breakage, except that aforementioned later commits will touch *all*
ExecInitResultTupleSlotTL() callers anyway (but fits worse
thematically).
Author: Andres Freund
Discussion: https://postgr.es/m/20181105210039.hh4vvi4vwoq5ba2q@alap3.anarazel.de
2018-11-10 02:19:39 +01:00
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* initialize child expressions
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2017-04-01 06:17:18 +02:00
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*/
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Don't require return slots for nodes without projection.
In a lot of nodes the return slot is not required. That can either be
because the node doesn't do any projection (say an Append node), or
because the node does perform projections but the projection is
optimized away because the projection would yield an identical row.
Slots aren't that small, especially for wide rows, so it's worthwhile
to avoid creating them. It's not possible to just skip creating the
slot - it's currently used to determine the tuple descriptor returned
by ExecGetResultType(). So separate the determination of the result
type from the slot creation. The work previously done internally
ExecInitResultTupleSlotTL() can now also be done separately with
ExecInitResultTypeTL() and ExecInitResultSlot(). That way nodes that
aren't guaranteed to need a result slot, can use
ExecInitResultTypeTL() to determine the result type of the node, and
ExecAssignScanProjectionInfo() (via
ExecConditionalAssignProjectionInfo()) determines that a result slot
is needed, it is created with ExecInitResultSlot().
Besides the advantage of avoiding to create slots that then are
unused, this is necessary preparation for later patches around tuple
table slot abstraction. In particular separating the return descriptor
and slot is a prerequisite to allow JITing of tuple deforming with
knowledge of the underlying tuple format, and to avoid unnecessarily
creating JITed tuple deforming for virtual slots.
This commit removes a redundant argument from
ExecInitResultTupleSlotTL(). While this commit touches a lot of the
relevant lines anyway, it'd normally still not worthwhile to cause
breakage, except that aforementioned later commits will touch *all*
ExecInitResultTupleSlotTL() callers anyway (but fits worse
thematically).
Author: Andres Freund
Discussion: https://postgr.es/m/20181105210039.hh4vvi4vwoq5ba2q@alap3.anarazel.de
2018-11-10 02:19:39 +01:00
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scanstate->ss.ps.qual =
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ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
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2017-04-01 06:17:18 +02:00
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return scanstate;
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}
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/* ----------------------------------------------------------------
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* ExecEndNamedTuplestoreScan
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*
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* frees any storage allocated through C routines.
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* ----------------------------------------------------------------
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*/
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void
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ExecEndNamedTuplestoreScan(NamedTuplestoreScanState *node)
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{
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/*
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* Free exprcontext
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*/
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ExecFreeExprContext(&node->ss.ps);
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/*
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* clean out the tuple table
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*/
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Don't require return slots for nodes without projection.
In a lot of nodes the return slot is not required. That can either be
because the node doesn't do any projection (say an Append node), or
because the node does perform projections but the projection is
optimized away because the projection would yield an identical row.
Slots aren't that small, especially for wide rows, so it's worthwhile
to avoid creating them. It's not possible to just skip creating the
slot - it's currently used to determine the tuple descriptor returned
by ExecGetResultType(). So separate the determination of the result
type from the slot creation. The work previously done internally
ExecInitResultTupleSlotTL() can now also be done separately with
ExecInitResultTypeTL() and ExecInitResultSlot(). That way nodes that
aren't guaranteed to need a result slot, can use
ExecInitResultTypeTL() to determine the result type of the node, and
ExecAssignScanProjectionInfo() (via
ExecConditionalAssignProjectionInfo()) determines that a result slot
is needed, it is created with ExecInitResultSlot().
Besides the advantage of avoiding to create slots that then are
unused, this is necessary preparation for later patches around tuple
table slot abstraction. In particular separating the return descriptor
and slot is a prerequisite to allow JITing of tuple deforming with
knowledge of the underlying tuple format, and to avoid unnecessarily
creating JITed tuple deforming for virtual slots.
This commit removes a redundant argument from
ExecInitResultTupleSlotTL(). While this commit touches a lot of the
relevant lines anyway, it'd normally still not worthwhile to cause
breakage, except that aforementioned later commits will touch *all*
ExecInitResultTupleSlotTL() callers anyway (but fits worse
thematically).
Author: Andres Freund
Discussion: https://postgr.es/m/20181105210039.hh4vvi4vwoq5ba2q@alap3.anarazel.de
2018-11-10 02:19:39 +01:00
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if (node->ss.ps.ps_ResultTupleSlot)
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ExecClearTuple(node->ss.ps.ps_ResultTupleSlot);
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2017-04-01 06:17:18 +02:00
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ExecClearTuple(node->ss.ss_ScanTupleSlot);
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}
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/* ----------------------------------------------------------------
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* ExecReScanNamedTuplestoreScan
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*
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* Rescans the relation.
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* ----------------------------------------------------------------
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*/
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void
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ExecReScanNamedTuplestoreScan(NamedTuplestoreScanState *node)
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{
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Tuplestorestate *tuplestorestate = node->relation;
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|
Don't require return slots for nodes without projection.
In a lot of nodes the return slot is not required. That can either be
because the node doesn't do any projection (say an Append node), or
because the node does perform projections but the projection is
optimized away because the projection would yield an identical row.
Slots aren't that small, especially for wide rows, so it's worthwhile
to avoid creating them. It's not possible to just skip creating the
slot - it's currently used to determine the tuple descriptor returned
by ExecGetResultType(). So separate the determination of the result
type from the slot creation. The work previously done internally
ExecInitResultTupleSlotTL() can now also be done separately with
ExecInitResultTypeTL() and ExecInitResultSlot(). That way nodes that
aren't guaranteed to need a result slot, can use
ExecInitResultTypeTL() to determine the result type of the node, and
ExecAssignScanProjectionInfo() (via
ExecConditionalAssignProjectionInfo()) determines that a result slot
is needed, it is created with ExecInitResultSlot().
Besides the advantage of avoiding to create slots that then are
unused, this is necessary preparation for later patches around tuple
table slot abstraction. In particular separating the return descriptor
and slot is a prerequisite to allow JITing of tuple deforming with
knowledge of the underlying tuple format, and to avoid unnecessarily
creating JITed tuple deforming for virtual slots.
This commit removes a redundant argument from
ExecInitResultTupleSlotTL(). While this commit touches a lot of the
relevant lines anyway, it'd normally still not worthwhile to cause
breakage, except that aforementioned later commits will touch *all*
ExecInitResultTupleSlotTL() callers anyway (but fits worse
thematically).
Author: Andres Freund
Discussion: https://postgr.es/m/20181105210039.hh4vvi4vwoq5ba2q@alap3.anarazel.de
2018-11-10 02:19:39 +01:00
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if (node->ss.ps.ps_ResultTupleSlot)
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ExecClearTuple(node->ss.ps.ps_ResultTupleSlot);
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2017-04-01 06:17:18 +02:00
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ExecScanReScan(&node->ss);
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/*
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* Rewind my own pointer.
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*/
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tuplestore_select_read_pointer(tuplestorestate, node->readptr);
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tuplestore_rescan(tuplestorestate);
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}
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