mirrors/postgres
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Speed up in-memory tuplesorting.

Browse Source 
Per recent work by Peter Geoghegan, it's significantly faster to
tuplesort on a single sortkey if ApplySortComparator is inlined into
quicksort rather reached via a function pointer.  It's also faster
in general to have a version of quicksort which is specialized for
sorting SortTuple objects rather than objects of arbitrary size and
type.  This requires a couple of additional copies of the quicksort
logic, which in this patch are generate using a Perl script.  There
might be some benefit in adding further specializations here too,
but thus far it's not clear that those gains are worth their weight
in code footprint.
This commit is contained in:
Robert Haas 2012-02-15 12:13:32 -05:00
parent ac9100f8cf
commit 337b6f5ecf
8 changed files with 289 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
src/backend/Makefile
View File

@ -202,6 +202,7 @@ distprep:
$(MAKE) -C replication repl_gram.c repl_scanner.c
$(MAKE) -C utils fmgrtab.c fmgroids.h errcodes.h
$(MAKE) -C utils/misc guc-file.c
$(MAKE) -C utils/sort qsort_tuple.c
##########################################################################
@ -315,7 +316,8 @@ maintainer-clean: distclean
utils/fmgroids.h \
utils/fmgrtab.c \
utils/errcodes.h \
utils/misc/guc-file.c
utils/misc/guc-file.c \
utils/misc/qsort_tuple.c
##########################################################################

1
src/backend/utils/sort/.gitignore vendored Normal file
View File

@ -0,0 +1 @@
/qsort_tuple.c

8
src/backend/utils/sort/Makefile
View File

@ -14,4 +14,12 @@ include $(top_builddir)/src/Makefile.global
OBJS = logtape.o sortsupport.o tuplesort.o tuplestore.o
tuplesort.o: qsort_tuple.c
qsort_tuple.c: gen_qsort_tuple.pl
$(PERL) $(srcdir)/gen_qsort_tuple.pl $< > $@
include $(top_srcdir)/src/backend/common.mk
maintainer-clean:
rm -f qsort_tuple.c

232
src/backend/utils/sort/gen_qsort_tuple.pl Normal file
View File

@ -0,0 +1,232 @@
#!/usr/bin/perl -w
#
# gen_qsort_tuple.pl
#
# This script generates specialized versions of the quicksort algorithm for
# tuple sorting. The quicksort code is derived from the NetBSD code. The
# code generated by this script runs significantly faster than vanilla qsort
# when used to sort tuples. This speedup comes from a number of places.
# The major effects are (1) inlining simple tuple comparators is much faster
# than jumping through a function pointer and (2) swap and vecswap operations
# specialized to the particular data type of interest (in this case, SortTuple)
# are faster than the generic routines.
#
# Modifications from vanilla NetBSD source:
# Add do ... while() macro fix
# Remove __inline, _DIAGASSERTs, __P
# Remove ill-considered "swap_cnt" switch to insertion sort,
# in favor of a simple check for presorted input.
# Instead of sorting arbitrary objects, we're always sorting SortTuples
# Add CHECK_FOR_INTERRUPTS()
#
# CAUTION: if you change this file, see also qsort.c and qsort_arg.c
#
use strict;
my $SUFFIX;
my $EXTRAARGS;
my $EXTRAPARAMS;
my $CMPPARAMS;
emit_qsort_boilerplate();
$SUFFIX = 'tuple';
$EXTRAARGS = ', SortTupleComparator cmp_tuple, Tuplesortstate *state';
$EXTRAPARAMS = ', cmp_tuple, state';
$CMPPARAMS = ', state';
emit_qsort_implementation();
$SUFFIX = 'ssup';
$EXTRAARGS = ', SortSupport ssup';
$EXTRAPARAMS = ', ssup';
$CMPPARAMS = ', ssup';
print <<'EOM';
#define cmp_ssup(a, b, ssup) \
ApplySortComparator((a)->datum1, (a)->isnull1, \
(b)->datum1, (b)->isnull1, ssup)
EOM
emit_qsort_implementation();
sub emit_qsort_boilerplate
{
print <<'EOM';
/*
* autogenerated by src/backend/utils/sort/gen_qsort_tuple.pl, do not edit
* This file is included by tuplesort.c, rather than compiled separately.
*/
/* $NetBSD: qsort.c,v 1.13 2003/08/07 16:43:42 agc Exp $ */
/*-
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Qsort routine based on J. L. Bentley and M. D. McIlroy,
* "Engineering a sort function",
* Software--Practice and Experience 23 (1993) 1249-1265.
* We have modified their original by adding a check for already-sorted input,
* which seems to be a win per discussions on pgsql-hackers around 2006-03-21.
*/
static void
swapfunc(SortTuple *a, SortTuple *b, size_t n)
{
do
{
SortTuple t = *a;
*a++ = *b;
*b++ = t;
} while (--n > 0);
}
#define swap(a, b) \
do { \
SortTuple t = *(a); \
*(a) = *(b); \
*(b) = t; \
} while (0);
#define vecswap(a, b, n) if ((n) > 0) swapfunc((a), (b), (size_t)(n))
EOM
}
sub emit_qsort_implementation
{
print <<EOM;
static SortTuple *
med3_$SUFFIX(SortTuple *a, SortTuple *b, SortTuple *c$EXTRAARGS)
{
return cmp_$SUFFIX(a, b$CMPPARAMS) < 0 ?
(cmp_$SUFFIX(b, c$CMPPARAMS) < 0 ? b :
(cmp_$SUFFIX(a, c$CMPPARAMS) < 0 ? c : a))
: (cmp_$SUFFIX(b, c$CMPPARAMS) > 0 ? b :
(cmp_$SUFFIX(a, c$CMPPARAMS) < 0 ? a : c));
}
static void
qsort_$SUFFIX(SortTuple *a, size_t n$EXTRAARGS)
{
SortTuple *pa,
*pb,
*pc,
*pd,
*pl,
*pm,
*pn;
int d,
r,
presorted;
loop:
CHECK_FOR_INTERRUPTS();
if (n < 7)
{
for (pm = a + 1; pm < a + n; pm++)
for (pl = pm; pl > a && cmp_$SUFFIX(pl - 1, pl$CMPPARAMS) > 0; pl--)
swap(pl, pl - 1);
return;
}
presorted = 1;
for (pm = a + 1; pm < a + n; pm++)
{
CHECK_FOR_INTERRUPTS();
if (cmp_$SUFFIX(pm - 1, pm$CMPPARAMS) > 0)
{
presorted = 0;
break;
}
}
if (presorted)
return;
pm = a + (n / 2);
if (n > 7)
{
pl = a;
pn = a + (n - 1);
if (n > 40)
{
d = (n / 8);
pl = med3_$SUFFIX(pl, pl + d, pl + 2 * d$EXTRAPARAMS);
pm = med3_$SUFFIX(pm - d, pm, pm + d$EXTRAPARAMS);
pn = med3_$SUFFIX(pn - 2 * d, pn - d, pn$EXTRAPARAMS);
}
pm = med3_$SUFFIX(pl, pm, pn$EXTRAPARAMS);
}
swap(a, pm);
pa = pb = a + 1;
pc = pd = a + (n - 1);
for (;;)
{
while (pb <= pc && (r = cmp_$SUFFIX(pb, a$CMPPARAMS)) <= 0)
{
CHECK_FOR_INTERRUPTS();
if (r == 0)
{
swap(pa, pb);
pa++;
}
pb++;
}
while (pb <= pc && (r = cmp_$SUFFIX(pc, a$CMPPARAMS)) >= 0)
{
CHECK_FOR_INTERRUPTS();
if (r == 0)
{
swap(pc, pd);
pd--;
}
pc--;
}
if (pb > pc)
break;
swap(pb, pc);
pb++;
pc--;
}
pn = a + n;
r = Min(pa - a, pb - pa);
vecswap(a, pb - r, r);
r = Min(pd - pc, pn - pd - 1);
vecswap(pb, pn - r, r);
if ((r = pb - pa) > 1)
qsort_$SUFFIX(a, r$EXTRAPARAMS);
if ((r = pd - pc) > 1)
{
/* Iterate rather than recurse to save stack space */
a = pn - r;
n = r;
goto loop;
}
/* qsort_$SUFFIX(pn - r, r$EXTRAPARAMS);*/
}
EOM
}

68
src/backend/utils/sort/tuplesort.c
View File

@ -195,6 +195,9 @@ typedef enum
#define TAPE_BUFFER_OVERHEAD (BLCKSZ * 3)
#define MERGE_BUFFER_SIZE (BLCKSZ * 32)
typedef int (*SortTupleComparator) (const SortTuple *a, const SortTuple *b,
Tuplesortstate *state);
/*
* Private state of a Tuplesort operation.
*/
@ -223,8 +226,7 @@ struct Tuplesortstate
* <0, 0, >0 according as a<b, a=b, a>b. The API must match
* qsort_arg_comparator.
*/
int (*comparetup) (const SortTuple *a, const SortTuple *b,
Tuplesortstate *state);
SortTupleComparator comparetup;
/*
* Function to copy a supplied input tuple into palloc'd space and set up
@ -363,12 +365,14 @@ struct Tuplesortstate
/* These are specific to the index_hash subcase: */
uint32 hash_mask; /* mask for sortable part of hash code */
/* This is initialized when, and only when, there's just one key. */
SortSupport onlyKey;
/*
* These variables are specific to the Datum case; they are set by
* tuplesort_begin_datum and used only by the DatumTuple routines.
*/
Oid datumType;
SortSupport datumKey;
/* we need typelen and byval in order to know how to copy the Datums. */
int datumTypeLen;
bool datumTypeByVal;
@ -492,6 +496,11 @@ static void readtup_datum(Tuplesortstate *state, SortTuple *stup,
static void reversedirection_datum(Tuplesortstate *state);
static void free_sort_tuple(Tuplesortstate *state, SortTuple *stup);
/*
* Special version of qsort, just for SortTuple objects.
*/
#include "qsort_tuple.c"
/*
* tuplesort_begin_xxx
@ -631,6 +640,9 @@ tuplesort_begin_heap(TupleDesc tupDesc,
PrepareSortSupportFromOrderingOp(sortOperators[i], sortKey);
}
if (nkeys == 1)
state->onlyKey = state->sortKeys;
MemoryContextSwitchTo(oldcontext);
return state;
@ -809,13 +821,13 @@ tuplesort_begin_datum(Oid datumType, Oid sortOperator, Oid sortCollation,
state->datumType = datumType;
/* Prepare SortSupport data */
state->datumKey = (SortSupport) palloc0(sizeof(SortSupportData));
state->onlyKey = (SortSupport) palloc0(sizeof(SortSupportData));
state->datumKey->ssup_cxt = CurrentMemoryContext;
state->datumKey->ssup_collation = sortCollation;
state->datumKey->ssup_nulls_first = nullsFirstFlag;
state->onlyKey->ssup_cxt = CurrentMemoryContext;
state->onlyKey->ssup_collation = sortCollation;
state->onlyKey->ssup_nulls_first = nullsFirstFlag;
PrepareSortSupportFromOrderingOp(sortOperator, state->datumKey);
PrepareSortSupportFromOrderingOp(sortOperator, state->onlyKey);
/* lookup necessary attributes of the datum type */
get_typlenbyval(datumType, &typlen, &typbyval);
@ -1222,11 +1234,16 @@ tuplesort_performsort(Tuplesortstate *state)
* amount of memory. Just qsort 'em and we're done.
*/
if (state->memtupcount > 1)
qsort_arg((void *) state->memtuples,
state->memtupcount,
sizeof(SortTuple),
(qsort_arg_comparator) state->comparetup,
(void *) state);
{
if (state->onlyKey != NULL)
qsort_ssup(state->memtuples, state->memtupcount,
state->onlyKey);
else
qsort_tuple(state->memtuples,
state->memtupcount,
state->comparetup,
state);
}
state->current = 0;
state->eof_reached = false;
state->markpos_offset = 0;
@ -2660,9 +2677,6 @@ comparetup_heap(const SortTuple *a, const SortTuple *b, Tuplesortstate *state)
int nkey;
int32 compare;
/* Allow interrupting long sorts */
CHECK_FOR_INTERRUPTS();
/* Compare the leading sort key */
compare = ApplySortComparator(a->datum1, a->isnull1,
b->datum1, b->isnull1,
@ -2804,9 +2818,6 @@ comparetup_cluster(const SortTuple *a, const SortTuple *b,
int nkey;
int32 compare;
/* Allow interrupting long sorts */
CHECK_FOR_INTERRUPTS();
/* Compare the leading sort key, if it's simple */
if (state->indexInfo->ii_KeyAttrNumbers[0] != 0)
{
@ -2995,9 +3006,6 @@ comparetup_index_btree(const SortTuple *a, const SortTuple *b,
int nkey;
int32 compare;
/* Allow interrupting long sorts */
CHECK_FOR_INTERRUPTS();
/* Compare the leading sort key */
compare = inlineApplySortFunction(&scanKey->sk_func, scanKey->sk_flags,
scanKey->sk_collation,
@ -3102,9 +3110,6 @@ comparetup_index_hash(const SortTuple *a, const SortTuple *b,
IndexTuple tuple1;
IndexTuple tuple2;
/* Allow interrupting long sorts */
CHECK_FOR_INTERRUPTS();
/*
* Fetch hash keys and mask off bits we don't want to sort by. We know
* that the first column of the index tuple is the hash key.
@ -3231,12 +3236,9 @@ reversedirection_index_hash(Tuplesortstate *state)
static int
comparetup_datum(const SortTuple *a, const SortTuple *b, Tuplesortstate *state)
{
/* Allow interrupting long sorts */
CHECK_FOR_INTERRUPTS();
return ApplySortComparator(a->datum1, a->isnull1,
b->datum1, b->isnull1,
state->datumKey);
/* Not currently needed */
elog(ERROR, "comparetup_datum() should not be called");
return 0;
}
static void
@ -3328,8 +3330,8 @@ readtup_datum(Tuplesortstate *state, SortTuple *stup,
static void
reversedirection_datum(Tuplesortstate *state)
{
state->datumKey->ssup_reverse = !state->datumKey->ssup_reverse;
state->datumKey->ssup_nulls_first = !state->datumKey->ssup_nulls_first;
state->onlyKey->ssup_reverse = !state->onlyKey->ssup_reverse;
state->onlyKey->ssup_nulls_first = !state->onlyKey->ssup_nulls_first;
}
/*

2
src/port/qsort.c
View File

@ -7,7 +7,7 @@
* Remove ill-considered "swap_cnt" switch to insertion sort,
* in favor of a simple check for presorted input.
*
* CAUTION: if you change this file, see also qsort_arg.c
* CAUTION: if you change this file, see also qsort_arg.c, gen_qsort_tuple.pl
*
* src/port/qsort.c
*/

2
src/port/qsort_arg.c
View File

@ -7,7 +7,7 @@
* Remove ill-considered "swap_cnt" switch to insertion sort,
* in favor of a simple check for presorted input.
*
* CAUTION: if you change this file, see also qsort.c
* CAUTION: if you change this file, see also qsort.c, gen_qsort_tuple.pl
*
* src/port/qsort_arg.c
*/

8
src/tools/msvc/Solution.pm
View File

@ -287,6 +287,14 @@ s{PG_VERSION_STR "[^"]+"}{__STRINGIFY(x) #x\n#define __STRINGIFY2(z) __STRINGIFY
);
}
if (IsNewer('src\backend\utils\sort\qsort_tuple.c','src\backend\utils\sort\gen_qsort_tuple.pl'))
{
print "Generating qsort_tuple.c...\n";
system(
'perl src\backend\utils\sort\gen_qsort_tuple.pl > src\backend\utils\sort\qsort_tuple.c'
);
}
if (IsNewer('src\interfaces\libpq\libpq.rc','src\interfaces\libpq\libpq.rc.in'))
{
print "Generating libpq.rc...\n";