tuplestore.h File Reference

#include "executor/tuptable.h"

Include dependency graph for tuplestore.h:

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Typedefs
typedef struct Tuplestorestate	Tuplestorestate

Functions
Tuplestorestate *	tuplestore_begin_heap (bool randomAccess, bool interXact, int maxKBytes)
void	tuplestore_set_eflags (Tuplestorestate *state, int eflags)
void	tuplestore_puttupleslot (Tuplestorestate *state, TupleTableSlot *slot)
void	tuplestore_puttuple (Tuplestorestate *state, HeapTuple tuple)
void	tuplestore_putvalues (Tuplestorestate *state, TupleDesc tdesc, const Datum *values, const bool *isnull)
int	tuplestore_alloc_read_pointer (Tuplestorestate *state, int eflags)
void	tuplestore_select_read_pointer (Tuplestorestate *state, int ptr)
void	tuplestore_copy_read_pointer (Tuplestorestate *state, int srcptr, int destptr)
void	tuplestore_trim (Tuplestorestate *state)
void	tuplestore_get_stats (Tuplestorestate *state, char **storage_type, int64 *max_space)
bool	tuplestore_in_memory (Tuplestorestate *state)
bool	tuplestore_gettupleslot (Tuplestorestate *state, bool forward, bool copy, TupleTableSlot *slot)
bool	tuplestore_advance (Tuplestorestate *state, bool forward)
bool	tuplestore_skiptuples (Tuplestorestate *state, int64 ntuples, bool forward)
int64	tuplestore_tuple_count (Tuplestorestate *state)
bool	tuplestore_ateof (Tuplestorestate *state)
void	tuplestore_rescan (Tuplestorestate *state)
void	tuplestore_clear (Tuplestorestate *state)
void	tuplestore_end (Tuplestorestate *state)

Typedef Documentation

Tuplestorestate

typedef struct Tuplestorestate Tuplestorestate

Definition at line 40 of file tuplestore.h.

Function Documentation

tuplestore_advance()

bool tuplestore_advance	(	Tuplestorestate *	state,
		bool	forward
	)

Definition at line 1162 of file tuplestore.c.

{
    void       *tuple;
    bool        should_free;
 
    tuple = tuplestore_gettuple(state, forward, &should_free);
 
    if (tuple)
    {
        if (should_free)
            pfree(tuple);
        return true;
    }
    else
    {
        return false;
    }
}

References pfree(), and tuplestore_gettuple().

Referenced by CteScanNext(), ExecMaterial(), and window_gettupleslot().

tuplestore_alloc_read_pointer()

int tuplestore_alloc_read_pointer	(	Tuplestorestate *	state,
		int	eflags
	)

Definition at line 395 of file tuplestore.c.

{
    /* Check for possible increase of requirements */
    if (state->status != TSS_INMEM || state->memtupcount != 0)
    {
        if ((state->eflags | eflags) != state->eflags)
            elog(ERROR, "too late to require new tuplestore eflags");
    }
 
    /* Make room for another read pointer if needed */
    if (state->readptrcount >= state->readptrsize)
    {
        int         newcnt = state->readptrsize * 2;
 
        state->readptrs = (TSReadPointer *)
            repalloc(state->readptrs, newcnt * sizeof(TSReadPointer));
        state->readptrsize = newcnt;
    }
 
    /* And set it up */
    state->readptrs[state->readptrcount] = state->readptrs[0];
    state->readptrs[state->readptrcount].eflags = eflags;
 
    state->eflags |= eflags;
 
    return state->readptrcount++;
}

References elog, ERROR, repalloc(), and TSS_INMEM.

Referenced by ExecInitCteScan(), ExecInitNamedTuplestoreScan(), ExecMaterial(), and prepare_tuplestore().

tuplestore_ateof()

bool tuplestore_ateof

(

Tuplestorestate *

state

)

Definition at line 591 of file tuplestore.c.

{
    return state->readptrs[state->activeptr].eof_reached;
}

Referenced by CteScanNext(), and ExecMaterial().

tuplestore_begin_heap()

Tuplestorestate * tuplestore_begin_heap	(	bool	randomAccess,
		bool	interXact,
		int	maxKBytes
	)

Definition at line 330 of file tuplestore.c.

{
    Tuplestorestate *state;
    int         eflags;
 
    /*
     * This interpretation of the meaning of randomAccess is compatible with
     * the pre-8.3 behavior of tuplestores.
     */
    eflags = randomAccess ?
        (EXEC_FLAG_BACKWARD | EXEC_FLAG_REWIND) :
        (EXEC_FLAG_REWIND);
 
    state = tuplestore_begin_common(eflags, interXact, maxKBytes);
 
    state->copytup = copytup_heap;
    state->writetup = writetup_heap;
    state->readtup = readtup_heap;
 
    return state;
}

References copytup_heap(), EXEC_FLAG_BACKWARD, EXEC_FLAG_REWIND, readtup_heap(), tuplestore_begin_common(), and writetup_heap().

Referenced by connectby(), crosstab(), exec_init_tuple_store(), ExecInitCteScan(), ExecInitRecursiveUnion(), ExecMakeTableFunctionResult(), ExecMaterial(), fmgr_sql(), get_crosstab_tuplestore(), GetCurrentFDWTuplestore(), InitMaterializedSRF(), libpqrcv_processTuples(), MakeTransitionCaptureState(), materializeResult(), plperl_return_next_internal(), pltcl_init_tuple_store(), populate_recordset_worker(), PortalCreateHoldStore(), prepare_tuplestore(), storeRow(), and tfuncFetchRows().

tuplestore_clear()

void tuplestore_clear

(

Tuplestorestate *

state

)

Definition at line 430 of file tuplestore.c.

{
    int         i;
    TSReadPointer *readptr;
 
    /* update the maxSpace before doing any USEMEM/FREEMEM adjustments */
    tuplestore_updatemax(state);
 
    if (state->myfile)
        BufFileClose(state->myfile);
    state->myfile = NULL;
 
#ifdef USE_ASSERT_CHECKING
    {
        int64       availMem = state->availMem;
 
        /*
         * Below, we reset the memory context for storing tuples.  To save
         * from having to always call GetMemoryChunkSpace() on all stored
         * tuples, we adjust the availMem to forget all the tuples and just
         * recall USEMEM for the space used by the memtuples array.  Here we
         * just Assert that's correct and the memory tracking hasn't gone
         * wrong anywhere.
         */
        for (i = state->memtupdeleted; i < state->memtupcount; i++)
            availMem += GetMemoryChunkSpace(state->memtuples[i]);
 
        availMem += GetMemoryChunkSpace(state->memtuples);
 
        Assert(availMem == state->allowedMem);
    }
#endif
 
    /* clear the memory consumed by the memory tuples */
    MemoryContextReset(state->context);
 
    /*
     * Zero the used memory and re-consume the space for the memtuples array.
     * This saves having to FREEMEM for each stored tuple.
     */
    state->availMem = state->allowedMem;
    USEMEM(state, GetMemoryChunkSpace(state->memtuples));
 
    state->status = TSS_INMEM;
    state->truncated = false;
    state->memtupdeleted = 0;
    state->memtupcount = 0;
    state->tuples = 0;
    readptr = state->readptrs;
    for (i = 0; i < state->readptrcount; readptr++, i++)
    {
        readptr->eof_reached = false;
        readptr->current = 0;
    }
}

References Assert, BufFileClose(), TSReadPointer::current, TSReadPointer::eof_reached, GetMemoryChunkSpace(), i, MemoryContextReset(), TSS_INMEM, tuplestore_updatemax(), and USEMEM.

Referenced by ExecRecursiveUnion(), ExecReScanCteScan(), ExecReScanRecursiveUnion(), fmgr_sql(), and release_partition().

tuplestore_copy_read_pointer()

void tuplestore_copy_read_pointer	(	Tuplestorestate *	state,
		int	srcptr,
		int	destptr
	)

Definition at line 1320 of file tuplestore.c.

{
    TSReadPointer *sptr = &state->readptrs[srcptr];
    TSReadPointer *dptr = &state->readptrs[destptr];
 
    Assert(srcptr >= 0 && srcptr < state->readptrcount);
    Assert(destptr >= 0 && destptr < state->readptrcount);
 
    /* Assigning to self is a no-op */
    if (srcptr == destptr)
        return;
 
    if (dptr->eflags != sptr->eflags)
    {
        /* Possible change of overall eflags, so copy and then recompute */
        int         eflags;
        int         i;
 
        *dptr = *sptr;
        eflags = state->readptrs[0].eflags;
        for (i = 1; i < state->readptrcount; i++)
            eflags |= state->readptrs[i].eflags;
        state->eflags = eflags;
    }
    else
        *dptr = *sptr;
 
    switch (state->status)
    {
        case TSS_INMEM:
        case TSS_WRITEFILE:
            /* no work */
            break;
        case TSS_READFILE:
 
            /*
             * This case is a bit tricky since the active read pointer's
             * position corresponds to the seek point, not what is in its
             * variables.  Assigning to the active requires a seek, and
             * assigning from the active requires a tell, except when
             * eof_reached.
             */
            if (destptr == state->activeptr)
            {
                if (dptr->eof_reached)
                {
                    if (BufFileSeek(state->myfile,
                                    state->writepos_file,
                                    state->writepos_offset,
                                    SEEK_SET) != 0)
                        ereport(ERROR,
                                (errcode_for_file_access(),
                                 errmsg("could not seek in tuplestore temporary file")));
                }
                else
                {
                    if (BufFileSeek(state->myfile,
                                    dptr->file, dptr->offset,
                                    SEEK_SET) != 0)
                        ereport(ERROR,
                                (errcode_for_file_access(),
                                 errmsg("could not seek in tuplestore temporary file")));
                }
            }
            else if (srcptr == state->activeptr)
            {
                if (!dptr->eof_reached)
                    BufFileTell(state->myfile,
                                &dptr->file,
                                &dptr->offset);
            }
            break;
        default:
            elog(ERROR, "invalid tuplestore state");
            break;
    }
}

References Assert, BufFileSeek(), BufFileTell(), TSReadPointer::eflags, elog, TSReadPointer::eof_reached, ereport, errcode_for_file_access(), errmsg(), ERROR, TSReadPointer::file, i, TSReadPointer::offset, TSS_INMEM, TSS_READFILE, and TSS_WRITEFILE.

Referenced by ExecMaterialMarkPos(), and ExecMaterialRestrPos().

tuplestore_end()

void tuplestore_end

(

Tuplestorestate *

state

)

Definition at line 492 of file tuplestore.c.

{
    if (state->myfile)
        BufFileClose(state->myfile);
 
    MemoryContextDelete(state->context);
    pfree(state->memtuples);
    pfree(state->readptrs);
    pfree(state);
}

References BufFileClose(), MemoryContextDelete(), and pfree().

Referenced by AfterTriggerFreeQuery(), ExecEndCteScan(), ExecEndFunctionScan(), ExecEndMaterial(), ExecEndRecursiveUnion(), ExecEndTableFuncScan(), ExecEndWindowAgg(), ExecMakeFunctionResultSet(), ExecReScanFunctionScan(), ExecReScanMaterial(), ExecReScanTableFuncScan(), PortalDrop(), ShutdownSetExpr(), ShutdownSQLFunction(), storeRow(), and walrcv_clear_result().

tuplestore_get_stats()

void tuplestore_get_stats	(	Tuplestorestate *	state,
		char **	storage_type,
		int64 *	max_space
	)

Definition at line 1533 of file tuplestore.c.

{
    tuplestore_updatemax(state);
 
    if (state->usedDisk)
        *max_storage_type = "Disk";
    else
        *max_storage_type = "Memory";
 
    *max_space = state->maxSpace;
}

References tuplestore_updatemax().

Referenced by show_ctescan_info(), show_material_info(), show_recursive_union_info(), show_table_func_scan_info(), and show_windowagg_info().

tuplestore_gettupleslot()

bool tuplestore_gettupleslot	(	Tuplestorestate *	state,
		bool	forward,
		bool	copy,
		TupleTableSlot *	slot
	)

Definition at line 1130 of file tuplestore.c.

{
    MinimalTuple tuple;
    bool        should_free;
 
    tuple = (MinimalTuple) tuplestore_gettuple(state, forward, &should_free);
 
    if (tuple)
    {
        if (copy && !should_free)
        {
            tuple = heap_copy_minimal_tuple(tuple);
            should_free = true;
        }
        ExecStoreMinimalTuple(tuple, slot, should_free);
        return true;
    }
    else
    {
        ExecClearTuple(slot);
        return false;
    }
}

References ExecClearTuple(), ExecStoreMinimalTuple(), heap_copy_minimal_tuple(), and tuplestore_gettuple().

Referenced by AfterTriggerExecute(), check_publications(), check_publications_origin(), CteScanNext(), ExecMakeFunctionResultSet(), ExecMaterial(), ExecWindowAgg(), fetch_remote_table_info(), fetch_table_list(), fmgr_sql(), FunctionNext(), NamedTuplestoreScanNext(), RunFromStore(), synchronize_slots(), TableFuncNext(), update_frameheadpos(), update_frametailpos(), update_grouptailpos(), validate_remote_info(), window_gettupleslot(), and WorkTableScanNext().

tuplestore_in_memory()

bool tuplestore_in_memory

(

Tuplestorestate *

state

)

Definition at line 1554 of file tuplestore.c.

{
    return (state->status == TSS_INMEM);
}

References TSS_INMEM.

Referenced by spool_tuples().

tuplestore_puttuple()

void tuplestore_puttuple	(	Tuplestorestate *	state,
		HeapTuple	tuple
	)

Definition at line 764 of file tuplestore.c.

{
    MemoryContext oldcxt = MemoryContextSwitchTo(state->context);
 
    /*
     * Copy the tuple.  (Must do this even in WRITEFILE case.  Note that
     * COPYTUP includes USEMEM, so we needn't do that here.)
     */
    tuple = COPYTUP(state, tuple);
 
    tuplestore_puttuple_common(state, tuple);
 
    MemoryContextSwitchTo(oldcxt);
}

References COPYTUP, MemoryContextSwitchTo(), and tuplestore_puttuple_common().

Referenced by build_tuplestore_recursively(), crosstab(), each_object_field_end(), elements_array_element_end(), exec_stmt_return_next(), ExecMakeTableFunctionResult(), fill_hba_line(), fill_ident_line(), get_crosstab_tuplestore(), libpqrcv_processTuples(), materializeResult(), pg_available_wal_summaries(), pg_wal_summary_contents(), pgrowlocks(), plperl_return_next_internal(), pltcl_returnnext(), populate_recordset_record(), report_corruption_internal(), storeRow(), and xpath_table().

tuplestore_puttupleslot()

void tuplestore_puttupleslot	(	Tuplestorestate *	state,
		TupleTableSlot *	slot
	)

Definition at line 742 of file tuplestore.c.

{
    MinimalTuple tuple;
    MemoryContext oldcxt = MemoryContextSwitchTo(state->context);
 
    /*
     * Form a MinimalTuple in working memory
     */
    tuple = ExecCopySlotMinimalTuple(slot);
    USEMEM(state, GetMemoryChunkSpace(tuple));
 
    tuplestore_puttuple_common(state, tuple);
 
    MemoryContextSwitchTo(oldcxt);
}

References ExecCopySlotMinimalTuple(), GetMemoryChunkSpace(), MemoryContextSwitchTo(), tuplestore_puttuple_common(), and USEMEM.

Referenced by AfterTriggerSaveEvent(), begin_partition(), CteScanNext(), ExecMaterial(), ExecRecursiveUnion(), spool_tuples(), sqlfunction_receive(), TransitionTableAddTuple(), tstoreReceiveSlot_notoast(), and tstoreReceiveSlot_tupmap().

tuplestore_putvalues()

void tuplestore_putvalues	(	Tuplestorestate *	state,
		TupleDesc	tdesc,
		const Datum *	values,
		const bool *	isnull
	)

Definition at line 784 of file tuplestore.c.

{
    MinimalTuple tuple;
    MemoryContext oldcxt = MemoryContextSwitchTo(state->context);
 
    tuple = heap_form_minimal_tuple(tdesc, values, isnull);
    USEMEM(state, GetMemoryChunkSpace(tuple));
 
    tuplestore_puttuple_common(state, tuple);
 
    MemoryContextSwitchTo(oldcxt);
}

References GetMemoryChunkSpace(), heap_form_minimal_tuple(), MemoryContextSwitchTo(), tuplestore_puttuple_common(), USEMEM, and values.

Referenced by brin_page_items(), dblink_get_notify(), each_worker_jsonb(), elements_worker_jsonb(), exec_stmt_return_next(), ExecMakeTableFunctionResult(), get_altertable_subcmdinfo(), get_available_versions_for_extension(), GetWALBlockInfo(), GetWALRecordsInfo(), GetXLogSummaryStats(), gist_page_items(), gist_page_items_bytea(), LogicalOutputWrite(), pg_available_extensions(), pg_config(), pg_cursor(), pg_event_trigger_ddl_commands(), pg_event_trigger_dropped_objects(), pg_extension_update_paths(), pg_get_replication_slots(), pg_get_shmem_allocations(), pg_get_wait_events(), pg_ls_dir(), pg_ls_dir_files(), pg_options_to_table(), pg_prepared_statement(), pg_show_replication_origin_status(), pg_stat_get_activity(), pg_stat_get_progress_info(), pg_stat_get_recovery_prefetch(), pg_stat_get_slru(), pg_stat_get_subscription(), pg_stat_get_wal_senders(), pg_stat_io_build_tuples(), pg_stat_statements_internal(), pg_tablespace_databases(), plperl_return_next_internal(), pltcl_returnnext(), postgres_fdw_get_connections_internal(), PutMemoryContextsStatsTupleStore(), show_all_file_settings(), split_text_accum_result(), tfuncLoadRows(), and tstoreReceiveSlot_detoast().

tuplestore_rescan()

void tuplestore_rescan

(

Tuplestorestate *

state

)

Definition at line 1285 of file tuplestore.c.

{
    TSReadPointer *readptr = &state->readptrs[state->activeptr];
 
    Assert(readptr->eflags & EXEC_FLAG_REWIND);
    Assert(!state->truncated);
 
    switch (state->status)
    {
        case TSS_INMEM:
            readptr->eof_reached = false;
            readptr->current = 0;
            break;
        case TSS_WRITEFILE:
            readptr->eof_reached = false;
            readptr->file = 0;
            readptr->offset = 0;
            break;
        case TSS_READFILE:
            readptr->eof_reached = false;
            if (BufFileSeek(state->myfile, 0, 0, SEEK_SET) != 0)
                ereport(ERROR,
                        (errcode_for_file_access(),
                         errmsg("could not seek in tuplestore temporary file")));
            break;
        default:
            elog(ERROR, "invalid tuplestore state");
            break;
    }
}

References Assert, BufFileSeek(), TSReadPointer::current, TSReadPointer::eflags, elog, TSReadPointer::eof_reached, ereport, errcode_for_file_access(), errmsg(), ERROR, EXEC_FLAG_REWIND, TSReadPointer::file, TSReadPointer::offset, TSS_INMEM, TSS_READFILE, and TSS_WRITEFILE.

Referenced by DoPortalRewind(), ExecInitCteScan(), ExecInitNamedTuplestoreScan(), ExecReScanCteScan(), ExecReScanFunctionScan(), ExecReScanMaterial(), ExecReScanNamedTuplestoreScan(), ExecReScanTableFuncScan(), ExecReScanWorkTableScan(), FunctionNext(), and PersistHoldablePortal().

tuplestore_select_read_pointer()

void tuplestore_select_read_pointer	(	Tuplestorestate *	state,
		int	ptr
	)

Definition at line 507 of file tuplestore.c.

{
    TSReadPointer *readptr;
    TSReadPointer *oldptr;
 
    Assert(ptr >= 0 && ptr < state->readptrcount);
 
    /* No work if already active */
    if (ptr == state->activeptr)
        return;
 
    readptr = &state->readptrs[ptr];
    oldptr = &state->readptrs[state->activeptr];
 
    switch (state->status)
    {
        case TSS_INMEM:
        case TSS_WRITEFILE:
            /* no work */
            break;
        case TSS_READFILE:
 
            /*
             * First, save the current read position in the pointer about to
             * become inactive.
             */
            if (!oldptr->eof_reached)
                BufFileTell(state->myfile,
                            &oldptr->file,
                            &oldptr->offset);
 
            /*
             * We have to make the temp file's seek position equal to the
             * logical position of the new read pointer.  In eof_reached
             * state, that's the EOF, which we have available from the saved
             * write position.
             */
            if (readptr->eof_reached)
            {
                if (BufFileSeek(state->myfile,
                                state->writepos_file,
                                state->writepos_offset,
                                SEEK_SET) != 0)
                    ereport(ERROR,
                            (errcode_for_file_access(),
                             errmsg("could not seek in tuplestore temporary file")));
            }
            else
            {
                if (BufFileSeek(state->myfile,
                                readptr->file,
                                readptr->offset,
                                SEEK_SET) != 0)
                    ereport(ERROR,
                            (errcode_for_file_access(),
                             errmsg("could not seek in tuplestore temporary file")));
            }
            break;
        default:
            elog(ERROR, "invalid tuplestore state");
            break;
    }
 
    state->activeptr = ptr;
}

References Assert, BufFileSeek(), BufFileTell(), elog, TSReadPointer::eof_reached, ereport, errcode_for_file_access(), errmsg(), ERROR, TSReadPointer::file, TSReadPointer::offset, TSS_INMEM, TSS_READFILE, and TSS_WRITEFILE.

Referenced by CteScanNext(), ExecInitCteScan(), ExecInitNamedTuplestoreScan(), ExecReScanCteScan(), ExecReScanNamedTuplestoreScan(), ExecWindowAgg(), NamedTuplestoreScanNext(), update_frameheadpos(), update_frametailpos(), update_grouptailpos(), window_gettupleslot(), and WinSetMarkPosition().

tuplestore_set_eflags()

void tuplestore_set_eflags	(	Tuplestorestate *	state,
		int	eflags
	)

Definition at line 371 of file tuplestore.c.

{
    int         i;
 
    if (state->status != TSS_INMEM || state->memtupcount != 0)
        elog(ERROR, "too late to call tuplestore_set_eflags");
 
    state->readptrs[0].eflags = eflags;
    for (i = 1; i < state->readptrcount; i++)
        eflags |= state->readptrs[i].eflags;
    state->eflags = eflags;
}

References elog, ERROR, i, and TSS_INMEM.

Referenced by ExecInitCteScan(), ExecMaterial(), and prepare_tuplestore().

tuplestore_skiptuples()

bool tuplestore_skiptuples	(	Tuplestorestate *	state,
		int64	ntuples,
		bool	forward
	)

Definition at line 1187 of file tuplestore.c.

{
    TSReadPointer *readptr = &state->readptrs[state->activeptr];
 
    Assert(forward || (readptr->eflags & EXEC_FLAG_BACKWARD));
 
    if (ntuples <= 0)
        return true;
 
    switch (state->status)
    {
        case TSS_INMEM:
            if (forward)
            {
                if (readptr->eof_reached)
                    return false;
                if (state->memtupcount - readptr->current >= ntuples)
                {
                    readptr->current += ntuples;
                    return true;
                }
                readptr->current = state->memtupcount;
                readptr->eof_reached = true;
                return false;
            }
            else
            {
                if (readptr->eof_reached)
                {
                    readptr->current = state->memtupcount;
                    readptr->eof_reached = false;
                    ntuples--;
                }
                if (readptr->current - state->memtupdeleted > ntuples)
                {
                    readptr->current -= ntuples;
                    return true;
                }
                Assert(!state->truncated);
                readptr->current = state->memtupdeleted;
                return false;
            }
            break;
 
        default:
            /* We don't currently try hard to optimize other cases */
            while (ntuples-- > 0)
            {
                void       *tuple;
                bool        should_free;
 
                tuple = tuplestore_gettuple(state, forward, &should_free);
 
                if (tuple == NULL)
                    return false;
                if (should_free)
                    pfree(tuple);
                CHECK_FOR_INTERRUPTS();
            }
            return true;
    }
}

References Assert, CHECK_FOR_INTERRUPTS, TSReadPointer::current, TSReadPointer::eflags, TSReadPointer::eof_reached, EXEC_FLAG_BACKWARD, pfree(), TSS_INMEM, and tuplestore_gettuple().

Referenced by PersistHoldablePortal(), window_gettupleslot(), and WinSetMarkPosition().

tuplestore_trim()

void tuplestore_trim

(

Tuplestorestate *

state

)

Definition at line 1412 of file tuplestore.c.

{
    int         oldest;
    int         nremove;
    int         i;
 
    /*
     * Truncation is disallowed if any read pointer requires rewind
     * capability.
     */
    if (state->eflags & EXEC_FLAG_REWIND)
        return;
 
    /*
     * We don't bother trimming temp files since it usually would mean more
     * work than just letting them sit in kernel buffers until they age out.
     */
    if (state->status != TSS_INMEM)
        return;
 
    /* Find the oldest read pointer */
    oldest = state->memtupcount;
    for (i = 0; i < state->readptrcount; i++)
    {
        if (!state->readptrs[i].eof_reached)
            oldest = Min(oldest, state->readptrs[i].current);
    }
 
    /*
     * Note: you might think we could remove all the tuples before the oldest
     * "current", since that one is the next to be returned.  However, since
     * tuplestore_gettuple returns a direct pointer to our internal copy of
     * the tuple, it's likely that the caller has still got the tuple just
     * before "current" referenced in a slot. So we keep one extra tuple
     * before the oldest "current".  (Strictly speaking, we could require such
     * callers to use the "copy" flag to tuplestore_gettupleslot, but for
     * efficiency we allow this one case to not use "copy".)
     */
    nremove = oldest - 1;
    if (nremove <= 0)
        return;                 /* nothing to do */
 
    Assert(nremove >= state->memtupdeleted);
    Assert(nremove <= state->memtupcount);
 
    /* before freeing any memory, update the statistics */
    tuplestore_updatemax(state);
 
    /* Release no-longer-needed tuples */
    for (i = state->memtupdeleted; i < nremove; i++)
    {
        FREEMEM(state, GetMemoryChunkSpace(state->memtuples[i]));
        pfree(state->memtuples[i]);
        state->memtuples[i] = NULL;
    }
    state->memtupdeleted = nremove;
 
    /* mark tuplestore as truncated (used for Assert crosschecks only) */
    state->truncated = true;
 
    /*
     * If nremove is less than 1/8th memtupcount, just stop here, leaving the
     * "deleted" slots as NULL.  This prevents us from expending O(N^2) time
     * repeatedly memmove-ing a large pointer array.  The worst case space
     * wastage is pretty small, since it's just pointers and not whole tuples.
     */
    if (nremove < state->memtupcount / 8)
        return;
 
    /*
     * Slide the array down and readjust pointers.
     *
     * In mergejoin's current usage, it's demonstrable that there will always
     * be exactly one non-removed tuple; so optimize that case.
     */
    if (nremove + 1 == state->memtupcount)
        state->memtuples[0] = state->memtuples[nremove];
    else
        memmove(state->memtuples, state->memtuples + nremove,
                (state->memtupcount - nremove) * sizeof(void *));
 
    state->memtupdeleted = 0;
    state->memtupcount -= nremove;
    for (i = 0; i < state->readptrcount; i++)
    {
        if (!state->readptrs[i].eof_reached)
            state->readptrs[i].current -= nremove;
    }
}

References Assert, EXEC_FLAG_REWIND, FREEMEM, GetMemoryChunkSpace(), i, Min, pfree(), TSS_INMEM, and tuplestore_updatemax().

Referenced by ExecMaterialMarkPos(), and ExecWindowAgg().

tuplestore_tuple_count()

int64 tuplestore_tuple_count

(

Tuplestorestate *

state

)

Definition at line 580 of file tuplestore.c.

{
    return state->tuples;
}

Referenced by exec_stmt_return_query(), fetch_remote_table_info(), and SPI_register_trigger_data().