Support "expanded" objects, particularly arrays, for better performance.
This patch introduces the ability for complex datatypes to have an
in-memory representation that is different from their on-disk format.
On-disk formats are typically optimized for minimal size, and in any case
they can't contain pointers, so they are often not well-suited for
computation. Now a datatype can invent an "expanded" in-memory format
that is better suited for its operations, and then pass that around among
the C functions that operate on the datatype. There are also provisions
(rudimentary as yet) to allow an expanded object to be modified in-place
under suitable conditions, so that operations like assignment to an element
of an array need not involve copying the entire array.
The initial application for this feature is arrays, but it is not hard
to foresee using it for other container types like JSON, XML and hstore.
I have hopes that it will be useful to PostGIS as well.
In this initial implementation, a few heuristics have been hard-wired
into plpgsql to improve performance for arrays that are stored in
plpgsql variables. We would like to generalize those hacks so that
other datatypes can obtain similar improvements, but figuring out some
appropriate APIs is left as a task for future work. (The heuristics
themselves are probably not optimal yet, either, as they sometimes
force expansion of arrays that would be better left alone.)
Preliminary performance testing shows impressive speed gains for plpgsql
functions that do element-by-element access or update of large arrays.
There are other cases that get a little slower, as a result of added array
format conversions; but we can hope to improve anything that's annoyingly
bad. In any case most applications should see a net win.
Tom Lane, reviewed by Andres Freund
2015-05-14 12:08:40 -04:00
|
|
|
/*-------------------------------------------------------------------------
|
|
|
|
|
*
|
|
|
|
|
* arrayaccess.h
|
|
|
|
|
* Declarations for element-by-element access to Postgres arrays.
|
|
|
|
|
*
|
|
|
|
|
*
|
2026-01-01 13:24:10 -05:00
|
|
|
* Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
|
Support "expanded" objects, particularly arrays, for better performance.
This patch introduces the ability for complex datatypes to have an
in-memory representation that is different from their on-disk format.
On-disk formats are typically optimized for minimal size, and in any case
they can't contain pointers, so they are often not well-suited for
computation. Now a datatype can invent an "expanded" in-memory format
that is better suited for its operations, and then pass that around among
the C functions that operate on the datatype. There are also provisions
(rudimentary as yet) to allow an expanded object to be modified in-place
under suitable conditions, so that operations like assignment to an element
of an array need not involve copying the entire array.
The initial application for this feature is arrays, but it is not hard
to foresee using it for other container types like JSON, XML and hstore.
I have hopes that it will be useful to PostGIS as well.
In this initial implementation, a few heuristics have been hard-wired
into plpgsql to improve performance for arrays that are stored in
plpgsql variables. We would like to generalize those hacks so that
other datatypes can obtain similar improvements, but figuring out some
appropriate APIs is left as a task for future work. (The heuristics
themselves are probably not optimal yet, either, as they sometimes
force expansion of arrays that would be better left alone.)
Preliminary performance testing shows impressive speed gains for plpgsql
functions that do element-by-element access or update of large arrays.
There are other cases that get a little slower, as a result of added array
format conversions; but we can hope to improve anything that's annoyingly
bad. In any case most applications should see a net win.
Tom Lane, reviewed by Andres Freund
2015-05-14 12:08:40 -04:00
|
|
|
* Portions Copyright (c) 1994, Regents of the University of California
|
|
|
|
|
*
|
|
|
|
|
* src/include/utils/arrayaccess.h
|
|
|
|
|
*
|
|
|
|
|
*-------------------------------------------------------------------------
|
|
|
|
|
*/
|
|
|
|
|
#ifndef ARRAYACCESS_H
|
|
|
|
|
#define ARRAYACCESS_H
|
|
|
|
|
|
|
|
|
|
#include "access/tupmacs.h"
|
|
|
|
|
#include "utils/array.h"
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Functions for iterating through elements of a flat or expanded array.
|
|
|
|
|
* These require a state struct "array_iter iter".
|
|
|
|
|
*
|
Refactor att_align_nominal() to improve performance.
Separate att_align_nominal() into two macros, similarly to what
was already done with att_align_datum() and att_align_pointer().
The inner macro att_nominal_alignby() is really just TYPEALIGN(),
while att_align_nominal() retains its previous API by mapping
TYPALIGN_xxx values to numbers of bytes to align to and then
calling att_nominal_alignby(). In support of this, split out
tupdesc.c's logic to do that mapping into a publicly visible
function typalign_to_alignby().
Having done that, we can replace performance-critical uses of
att_align_nominal() with att_nominal_alignby(), where the
typalign_to_alignby() mapping is done just once outside the loop.
In most places I settled for doing typalign_to_alignby() once
per function. We could in many places pass the alignby value
in from the caller if we wanted to change function APIs for this
purpose; but I'm a bit loath to do that, especially for exported
APIs that extensions might call. Replacing a char typalign
argument by a uint8 typalignby argument would be an API change
that compilers would fail to warn about, thus silently breaking
code in hard-to-debug ways. I did revise the APIs of array_iter_setup
and array_iter_next, moving the element type attribute arguments to
the former; if any external code uses those, the argument-count
change will cause visible compile failures.
Performance testing shows that ExecEvalScalarArrayOp is sped up by
about 10% by this change, when using a simple per-element function
such as int8eq. I did not check any of the other loops optimized
here, but it's reasonable to expect similar gains.
Although the motivation for creating this patch was to avoid a
performance loss if we add some more typalign values, it evidently
is worth doing whether that patch lands or not.
Discussion: https://postgr.es/m/1127261.1769649624@sss.pgh.pa.us
2026-02-02 14:39:50 -05:00
|
|
|
* Use "array_iter_setup(&iter, arrayptr, ...);" to prepare to iterate,
|
|
|
|
|
* and "datumvar = array_iter_next(&iter, &isnullvar, index);" to fetch
|
Support "expanded" objects, particularly arrays, for better performance.
This patch introduces the ability for complex datatypes to have an
in-memory representation that is different from their on-disk format.
On-disk formats are typically optimized for minimal size, and in any case
they can't contain pointers, so they are often not well-suited for
computation. Now a datatype can invent an "expanded" in-memory format
that is better suited for its operations, and then pass that around among
the C functions that operate on the datatype. There are also provisions
(rudimentary as yet) to allow an expanded object to be modified in-place
under suitable conditions, so that operations like assignment to an element
of an array need not involve copying the entire array.
The initial application for this feature is arrays, but it is not hard
to foresee using it for other container types like JSON, XML and hstore.
I have hopes that it will be useful to PostGIS as well.
In this initial implementation, a few heuristics have been hard-wired
into plpgsql to improve performance for arrays that are stored in
plpgsql variables. We would like to generalize those hacks so that
other datatypes can obtain similar improvements, but figuring out some
appropriate APIs is left as a task for future work. (The heuristics
themselves are probably not optimal yet, either, as they sometimes
force expansion of arrays that would be better left alone.)
Preliminary performance testing shows impressive speed gains for plpgsql
functions that do element-by-element access or update of large arrays.
There are other cases that get a little slower, as a result of added array
format conversions; but we can hope to improve anything that's annoyingly
bad. In any case most applications should see a net win.
Tom Lane, reviewed by Andres Freund
2015-05-14 12:08:40 -04:00
|
|
|
* the next element into datumvar/isnullvar.
|
|
|
|
|
* "index" must be the zero-origin element number; we make caller provide
|
|
|
|
|
* this since caller is generally counting the elements anyway. Despite
|
|
|
|
|
* that, these functions can only fetch elements sequentially.
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
typedef struct array_iter
|
|
|
|
|
{
|
|
|
|
|
/* datumptr being NULL or not tells if we have flat or expanded array */
|
|
|
|
|
|
|
|
|
|
/* Fields used when we have an expanded array */
|
|
|
|
|
Datum *datumptr; /* Pointer to Datum array */
|
|
|
|
|
bool *isnullptr; /* Pointer to isnull array */
|
|
|
|
|
|
|
|
|
|
/* Fields used when we have a flat array */
|
|
|
|
|
char *dataptr; /* Current spot in the data area */
|
|
|
|
|
bits8 *bitmapptr; /* Current byte of the nulls bitmap, or NULL */
|
|
|
|
|
int bitmask; /* mask for current bit in nulls bitmap */
|
Refactor att_align_nominal() to improve performance.
Separate att_align_nominal() into two macros, similarly to what
was already done with att_align_datum() and att_align_pointer().
The inner macro att_nominal_alignby() is really just TYPEALIGN(),
while att_align_nominal() retains its previous API by mapping
TYPALIGN_xxx values to numbers of bytes to align to and then
calling att_nominal_alignby(). In support of this, split out
tupdesc.c's logic to do that mapping into a publicly visible
function typalign_to_alignby().
Having done that, we can replace performance-critical uses of
att_align_nominal() with att_nominal_alignby(), where the
typalign_to_alignby() mapping is done just once outside the loop.
In most places I settled for doing typalign_to_alignby() once
per function. We could in many places pass the alignby value
in from the caller if we wanted to change function APIs for this
purpose; but I'm a bit loath to do that, especially for exported
APIs that extensions might call. Replacing a char typalign
argument by a uint8 typalignby argument would be an API change
that compilers would fail to warn about, thus silently breaking
code in hard-to-debug ways. I did revise the APIs of array_iter_setup
and array_iter_next, moving the element type attribute arguments to
the former; if any external code uses those, the argument-count
change will cause visible compile failures.
Performance testing shows that ExecEvalScalarArrayOp is sped up by
about 10% by this change, when using a simple per-element function
such as int8eq. I did not check any of the other loops optimized
here, but it's reasonable to expect similar gains.
Although the motivation for creating this patch was to avoid a
performance loss if we add some more typalign values, it evidently
is worth doing whether that patch lands or not.
Discussion: https://postgr.es/m/1127261.1769649624@sss.pgh.pa.us
2026-02-02 14:39:50 -05:00
|
|
|
|
|
|
|
|
/* Fields used in both cases: data about array's element type */
|
|
|
|
|
int elmlen;
|
|
|
|
|
bool elmbyval;
|
|
|
|
|
uint8 elmalignby;
|
Support "expanded" objects, particularly arrays, for better performance.
This patch introduces the ability for complex datatypes to have an
in-memory representation that is different from their on-disk format.
On-disk formats are typically optimized for minimal size, and in any case
they can't contain pointers, so they are often not well-suited for
computation. Now a datatype can invent an "expanded" in-memory format
that is better suited for its operations, and then pass that around among
the C functions that operate on the datatype. There are also provisions
(rudimentary as yet) to allow an expanded object to be modified in-place
under suitable conditions, so that operations like assignment to an element
of an array need not involve copying the entire array.
The initial application for this feature is arrays, but it is not hard
to foresee using it for other container types like JSON, XML and hstore.
I have hopes that it will be useful to PostGIS as well.
In this initial implementation, a few heuristics have been hard-wired
into plpgsql to improve performance for arrays that are stored in
plpgsql variables. We would like to generalize those hacks so that
other datatypes can obtain similar improvements, but figuring out some
appropriate APIs is left as a task for future work. (The heuristics
themselves are probably not optimal yet, either, as they sometimes
force expansion of arrays that would be better left alone.)
Preliminary performance testing shows impressive speed gains for plpgsql
functions that do element-by-element access or update of large arrays.
There are other cases that get a little slower, as a result of added array
format conversions; but we can hope to improve anything that's annoyingly
bad. In any case most applications should see a net win.
Tom Lane, reviewed by Andres Freund
2015-05-14 12:08:40 -04:00
|
|
|
} array_iter;
|
|
|
|
|
|
|
|
|
|
|
2015-08-05 12:19:52 -04:00
|
|
|
static inline void
|
Refactor att_align_nominal() to improve performance.
Separate att_align_nominal() into two macros, similarly to what
was already done with att_align_datum() and att_align_pointer().
The inner macro att_nominal_alignby() is really just TYPEALIGN(),
while att_align_nominal() retains its previous API by mapping
TYPALIGN_xxx values to numbers of bytes to align to and then
calling att_nominal_alignby(). In support of this, split out
tupdesc.c's logic to do that mapping into a publicly visible
function typalign_to_alignby().
Having done that, we can replace performance-critical uses of
att_align_nominal() with att_nominal_alignby(), where the
typalign_to_alignby() mapping is done just once outside the loop.
In most places I settled for doing typalign_to_alignby() once
per function. We could in many places pass the alignby value
in from the caller if we wanted to change function APIs for this
purpose; but I'm a bit loath to do that, especially for exported
APIs that extensions might call. Replacing a char typalign
argument by a uint8 typalignby argument would be an API change
that compilers would fail to warn about, thus silently breaking
code in hard-to-debug ways. I did revise the APIs of array_iter_setup
and array_iter_next, moving the element type attribute arguments to
the former; if any external code uses those, the argument-count
change will cause visible compile failures.
Performance testing shows that ExecEvalScalarArrayOp is sped up by
about 10% by this change, when using a simple per-element function
such as int8eq. I did not check any of the other loops optimized
here, but it's reasonable to expect similar gains.
Although the motivation for creating this patch was to avoid a
performance loss if we add some more typalign values, it evidently
is worth doing whether that patch lands or not.
Discussion: https://postgr.es/m/1127261.1769649624@sss.pgh.pa.us
2026-02-02 14:39:50 -05:00
|
|
|
array_iter_setup(array_iter *it, AnyArrayType *a,
|
|
|
|
|
int elmlen, bool elmbyval, char elmalign)
|
Support "expanded" objects, particularly arrays, for better performance.
This patch introduces the ability for complex datatypes to have an
in-memory representation that is different from their on-disk format.
On-disk formats are typically optimized for minimal size, and in any case
they can't contain pointers, so they are often not well-suited for
computation. Now a datatype can invent an "expanded" in-memory format
that is better suited for its operations, and then pass that around among
the C functions that operate on the datatype. There are also provisions
(rudimentary as yet) to allow an expanded object to be modified in-place
under suitable conditions, so that operations like assignment to an element
of an array need not involve copying the entire array.
The initial application for this feature is arrays, but it is not hard
to foresee using it for other container types like JSON, XML and hstore.
I have hopes that it will be useful to PostGIS as well.
In this initial implementation, a few heuristics have been hard-wired
into plpgsql to improve performance for arrays that are stored in
plpgsql variables. We would like to generalize those hacks so that
other datatypes can obtain similar improvements, but figuring out some
appropriate APIs is left as a task for future work. (The heuristics
themselves are probably not optimal yet, either, as they sometimes
force expansion of arrays that would be better left alone.)
Preliminary performance testing shows impressive speed gains for plpgsql
functions that do element-by-element access or update of large arrays.
There are other cases that get a little slower, as a result of added array
format conversions; but we can hope to improve anything that's annoyingly
bad. In any case most applications should see a net win.
Tom Lane, reviewed by Andres Freund
2015-05-14 12:08:40 -04:00
|
|
|
{
|
|
|
|
|
if (VARATT_IS_EXPANDED_HEADER(a))
|
|
|
|
|
{
|
|
|
|
|
if (a->xpn.dvalues)
|
|
|
|
|
{
|
|
|
|
|
it->datumptr = a->xpn.dvalues;
|
|
|
|
|
it->isnullptr = a->xpn.dnulls;
|
|
|
|
|
/* we must fill all fields to prevent compiler warnings */
|
|
|
|
|
it->dataptr = NULL;
|
|
|
|
|
it->bitmapptr = NULL;
|
|
|
|
|
}
|
|
|
|
|
else
|
|
|
|
|
{
|
|
|
|
|
/* Work with flat array embedded in the expanded datum */
|
|
|
|
|
it->datumptr = NULL;
|
|
|
|
|
it->isnullptr = NULL;
|
|
|
|
|
it->dataptr = ARR_DATA_PTR(a->xpn.fvalue);
|
|
|
|
|
it->bitmapptr = ARR_NULLBITMAP(a->xpn.fvalue);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
else
|
|
|
|
|
{
|
|
|
|
|
it->datumptr = NULL;
|
|
|
|
|
it->isnullptr = NULL;
|
2019-06-30 20:34:17 -04:00
|
|
|
it->dataptr = ARR_DATA_PTR((ArrayType *) a);
|
|
|
|
|
it->bitmapptr = ARR_NULLBITMAP((ArrayType *) a);
|
Support "expanded" objects, particularly arrays, for better performance.
This patch introduces the ability for complex datatypes to have an
in-memory representation that is different from their on-disk format.
On-disk formats are typically optimized for minimal size, and in any case
they can't contain pointers, so they are often not well-suited for
computation. Now a datatype can invent an "expanded" in-memory format
that is better suited for its operations, and then pass that around among
the C functions that operate on the datatype. There are also provisions
(rudimentary as yet) to allow an expanded object to be modified in-place
under suitable conditions, so that operations like assignment to an element
of an array need not involve copying the entire array.
The initial application for this feature is arrays, but it is not hard
to foresee using it for other container types like JSON, XML and hstore.
I have hopes that it will be useful to PostGIS as well.
In this initial implementation, a few heuristics have been hard-wired
into plpgsql to improve performance for arrays that are stored in
plpgsql variables. We would like to generalize those hacks so that
other datatypes can obtain similar improvements, but figuring out some
appropriate APIs is left as a task for future work. (The heuristics
themselves are probably not optimal yet, either, as they sometimes
force expansion of arrays that would be better left alone.)
Preliminary performance testing shows impressive speed gains for plpgsql
functions that do element-by-element access or update of large arrays.
There are other cases that get a little slower, as a result of added array
format conversions; but we can hope to improve anything that's annoyingly
bad. In any case most applications should see a net win.
Tom Lane, reviewed by Andres Freund
2015-05-14 12:08:40 -04:00
|
|
|
}
|
|
|
|
|
it->bitmask = 1;
|
Refactor att_align_nominal() to improve performance.
Separate att_align_nominal() into two macros, similarly to what
was already done with att_align_datum() and att_align_pointer().
The inner macro att_nominal_alignby() is really just TYPEALIGN(),
while att_align_nominal() retains its previous API by mapping
TYPALIGN_xxx values to numbers of bytes to align to and then
calling att_nominal_alignby(). In support of this, split out
tupdesc.c's logic to do that mapping into a publicly visible
function typalign_to_alignby().
Having done that, we can replace performance-critical uses of
att_align_nominal() with att_nominal_alignby(), where the
typalign_to_alignby() mapping is done just once outside the loop.
In most places I settled for doing typalign_to_alignby() once
per function. We could in many places pass the alignby value
in from the caller if we wanted to change function APIs for this
purpose; but I'm a bit loath to do that, especially for exported
APIs that extensions might call. Replacing a char typalign
argument by a uint8 typalignby argument would be an API change
that compilers would fail to warn about, thus silently breaking
code in hard-to-debug ways. I did revise the APIs of array_iter_setup
and array_iter_next, moving the element type attribute arguments to
the former; if any external code uses those, the argument-count
change will cause visible compile failures.
Performance testing shows that ExecEvalScalarArrayOp is sped up by
about 10% by this change, when using a simple per-element function
such as int8eq. I did not check any of the other loops optimized
here, but it's reasonable to expect similar gains.
Although the motivation for creating this patch was to avoid a
performance loss if we add some more typalign values, it evidently
is worth doing whether that patch lands or not.
Discussion: https://postgr.es/m/1127261.1769649624@sss.pgh.pa.us
2026-02-02 14:39:50 -05:00
|
|
|
it->elmlen = elmlen;
|
|
|
|
|
it->elmbyval = elmbyval;
|
|
|
|
|
it->elmalignby = typalign_to_alignby(elmalign);
|
Support "expanded" objects, particularly arrays, for better performance.
This patch introduces the ability for complex datatypes to have an
in-memory representation that is different from their on-disk format.
On-disk formats are typically optimized for minimal size, and in any case
they can't contain pointers, so they are often not well-suited for
computation. Now a datatype can invent an "expanded" in-memory format
that is better suited for its operations, and then pass that around among
the C functions that operate on the datatype. There are also provisions
(rudimentary as yet) to allow an expanded object to be modified in-place
under suitable conditions, so that operations like assignment to an element
of an array need not involve copying the entire array.
The initial application for this feature is arrays, but it is not hard
to foresee using it for other container types like JSON, XML and hstore.
I have hopes that it will be useful to PostGIS as well.
In this initial implementation, a few heuristics have been hard-wired
into plpgsql to improve performance for arrays that are stored in
plpgsql variables. We would like to generalize those hacks so that
other datatypes can obtain similar improvements, but figuring out some
appropriate APIs is left as a task for future work. (The heuristics
themselves are probably not optimal yet, either, as they sometimes
force expansion of arrays that would be better left alone.)
Preliminary performance testing shows impressive speed gains for plpgsql
functions that do element-by-element access or update of large arrays.
There are other cases that get a little slower, as a result of added array
format conversions; but we can hope to improve anything that's annoyingly
bad. In any case most applications should see a net win.
Tom Lane, reviewed by Andres Freund
2015-05-14 12:08:40 -04:00
|
|
|
}
|
|
|
|
|
|
2015-08-05 12:19:52 -04:00
|
|
|
static inline Datum
|
Refactor att_align_nominal() to improve performance.
Separate att_align_nominal() into two macros, similarly to what
was already done with att_align_datum() and att_align_pointer().
The inner macro att_nominal_alignby() is really just TYPEALIGN(),
while att_align_nominal() retains its previous API by mapping
TYPALIGN_xxx values to numbers of bytes to align to and then
calling att_nominal_alignby(). In support of this, split out
tupdesc.c's logic to do that mapping into a publicly visible
function typalign_to_alignby().
Having done that, we can replace performance-critical uses of
att_align_nominal() with att_nominal_alignby(), where the
typalign_to_alignby() mapping is done just once outside the loop.
In most places I settled for doing typalign_to_alignby() once
per function. We could in many places pass the alignby value
in from the caller if we wanted to change function APIs for this
purpose; but I'm a bit loath to do that, especially for exported
APIs that extensions might call. Replacing a char typalign
argument by a uint8 typalignby argument would be an API change
that compilers would fail to warn about, thus silently breaking
code in hard-to-debug ways. I did revise the APIs of array_iter_setup
and array_iter_next, moving the element type attribute arguments to
the former; if any external code uses those, the argument-count
change will cause visible compile failures.
Performance testing shows that ExecEvalScalarArrayOp is sped up by
about 10% by this change, when using a simple per-element function
such as int8eq. I did not check any of the other loops optimized
here, but it's reasonable to expect similar gains.
Although the motivation for creating this patch was to avoid a
performance loss if we add some more typalign values, it evidently
is worth doing whether that patch lands or not.
Discussion: https://postgr.es/m/1127261.1769649624@sss.pgh.pa.us
2026-02-02 14:39:50 -05:00
|
|
|
array_iter_next(array_iter *it, bool *isnull, int i)
|
Support "expanded" objects, particularly arrays, for better performance.
This patch introduces the ability for complex datatypes to have an
in-memory representation that is different from their on-disk format.
On-disk formats are typically optimized for minimal size, and in any case
they can't contain pointers, so they are often not well-suited for
computation. Now a datatype can invent an "expanded" in-memory format
that is better suited for its operations, and then pass that around among
the C functions that operate on the datatype. There are also provisions
(rudimentary as yet) to allow an expanded object to be modified in-place
under suitable conditions, so that operations like assignment to an element
of an array need not involve copying the entire array.
The initial application for this feature is arrays, but it is not hard
to foresee using it for other container types like JSON, XML and hstore.
I have hopes that it will be useful to PostGIS as well.
In this initial implementation, a few heuristics have been hard-wired
into plpgsql to improve performance for arrays that are stored in
plpgsql variables. We would like to generalize those hacks so that
other datatypes can obtain similar improvements, but figuring out some
appropriate APIs is left as a task for future work. (The heuristics
themselves are probably not optimal yet, either, as they sometimes
force expansion of arrays that would be better left alone.)
Preliminary performance testing shows impressive speed gains for plpgsql
functions that do element-by-element access or update of large arrays.
There are other cases that get a little slower, as a result of added array
format conversions; but we can hope to improve anything that's annoyingly
bad. In any case most applications should see a net win.
Tom Lane, reviewed by Andres Freund
2015-05-14 12:08:40 -04:00
|
|
|
{
|
|
|
|
|
Datum ret;
|
|
|
|
|
|
|
|
|
|
if (it->datumptr)
|
|
|
|
|
{
|
|
|
|
|
ret = it->datumptr[i];
|
|
|
|
|
*isnull = it->isnullptr ? it->isnullptr[i] : false;
|
|
|
|
|
}
|
|
|
|
|
else
|
|
|
|
|
{
|
|
|
|
|
if (it->bitmapptr && (*(it->bitmapptr) & it->bitmask) == 0)
|
|
|
|
|
{
|
|
|
|
|
*isnull = true;
|
|
|
|
|
ret = (Datum) 0;
|
|
|
|
|
}
|
|
|
|
|
else
|
|
|
|
|
{
|
|
|
|
|
*isnull = false;
|
Refactor att_align_nominal() to improve performance.
Separate att_align_nominal() into two macros, similarly to what
was already done with att_align_datum() and att_align_pointer().
The inner macro att_nominal_alignby() is really just TYPEALIGN(),
while att_align_nominal() retains its previous API by mapping
TYPALIGN_xxx values to numbers of bytes to align to and then
calling att_nominal_alignby(). In support of this, split out
tupdesc.c's logic to do that mapping into a publicly visible
function typalign_to_alignby().
Having done that, we can replace performance-critical uses of
att_align_nominal() with att_nominal_alignby(), where the
typalign_to_alignby() mapping is done just once outside the loop.
In most places I settled for doing typalign_to_alignby() once
per function. We could in many places pass the alignby value
in from the caller if we wanted to change function APIs for this
purpose; but I'm a bit loath to do that, especially for exported
APIs that extensions might call. Replacing a char typalign
argument by a uint8 typalignby argument would be an API change
that compilers would fail to warn about, thus silently breaking
code in hard-to-debug ways. I did revise the APIs of array_iter_setup
and array_iter_next, moving the element type attribute arguments to
the former; if any external code uses those, the argument-count
change will cause visible compile failures.
Performance testing shows that ExecEvalScalarArrayOp is sped up by
about 10% by this change, when using a simple per-element function
such as int8eq. I did not check any of the other loops optimized
here, but it's reasonable to expect similar gains.
Although the motivation for creating this patch was to avoid a
performance loss if we add some more typalign values, it evidently
is worth doing whether that patch lands or not.
Discussion: https://postgr.es/m/1127261.1769649624@sss.pgh.pa.us
2026-02-02 14:39:50 -05:00
|
|
|
ret = fetch_att(it->dataptr, it->elmbyval, it->elmlen);
|
|
|
|
|
it->dataptr = att_addlength_pointer(it->dataptr, it->elmlen,
|
Support "expanded" objects, particularly arrays, for better performance.
This patch introduces the ability for complex datatypes to have an
in-memory representation that is different from their on-disk format.
On-disk formats are typically optimized for minimal size, and in any case
they can't contain pointers, so they are often not well-suited for
computation. Now a datatype can invent an "expanded" in-memory format
that is better suited for its operations, and then pass that around among
the C functions that operate on the datatype. There are also provisions
(rudimentary as yet) to allow an expanded object to be modified in-place
under suitable conditions, so that operations like assignment to an element
of an array need not involve copying the entire array.
The initial application for this feature is arrays, but it is not hard
to foresee using it for other container types like JSON, XML and hstore.
I have hopes that it will be useful to PostGIS as well.
In this initial implementation, a few heuristics have been hard-wired
into plpgsql to improve performance for arrays that are stored in
plpgsql variables. We would like to generalize those hacks so that
other datatypes can obtain similar improvements, but figuring out some
appropriate APIs is left as a task for future work. (The heuristics
themselves are probably not optimal yet, either, as they sometimes
force expansion of arrays that would be better left alone.)
Preliminary performance testing shows impressive speed gains for plpgsql
functions that do element-by-element access or update of large arrays.
There are other cases that get a little slower, as a result of added array
format conversions; but we can hope to improve anything that's annoyingly
bad. In any case most applications should see a net win.
Tom Lane, reviewed by Andres Freund
2015-05-14 12:08:40 -04:00
|
|
|
it->dataptr);
|
Refactor att_align_nominal() to improve performance.
Separate att_align_nominal() into two macros, similarly to what
was already done with att_align_datum() and att_align_pointer().
The inner macro att_nominal_alignby() is really just TYPEALIGN(),
while att_align_nominal() retains its previous API by mapping
TYPALIGN_xxx values to numbers of bytes to align to and then
calling att_nominal_alignby(). In support of this, split out
tupdesc.c's logic to do that mapping into a publicly visible
function typalign_to_alignby().
Having done that, we can replace performance-critical uses of
att_align_nominal() with att_nominal_alignby(), where the
typalign_to_alignby() mapping is done just once outside the loop.
In most places I settled for doing typalign_to_alignby() once
per function. We could in many places pass the alignby value
in from the caller if we wanted to change function APIs for this
purpose; but I'm a bit loath to do that, especially for exported
APIs that extensions might call. Replacing a char typalign
argument by a uint8 typalignby argument would be an API change
that compilers would fail to warn about, thus silently breaking
code in hard-to-debug ways. I did revise the APIs of array_iter_setup
and array_iter_next, moving the element type attribute arguments to
the former; if any external code uses those, the argument-count
change will cause visible compile failures.
Performance testing shows that ExecEvalScalarArrayOp is sped up by
about 10% by this change, when using a simple per-element function
such as int8eq. I did not check any of the other loops optimized
here, but it's reasonable to expect similar gains.
Although the motivation for creating this patch was to avoid a
performance loss if we add some more typalign values, it evidently
is worth doing whether that patch lands or not.
Discussion: https://postgr.es/m/1127261.1769649624@sss.pgh.pa.us
2026-02-02 14:39:50 -05:00
|
|
|
it->dataptr = (char *) att_nominal_alignby(it->dataptr,
|
|
|
|
|
it->elmalignby);
|
Support "expanded" objects, particularly arrays, for better performance.
This patch introduces the ability for complex datatypes to have an
in-memory representation that is different from their on-disk format.
On-disk formats are typically optimized for minimal size, and in any case
they can't contain pointers, so they are often not well-suited for
computation. Now a datatype can invent an "expanded" in-memory format
that is better suited for its operations, and then pass that around among
the C functions that operate on the datatype. There are also provisions
(rudimentary as yet) to allow an expanded object to be modified in-place
under suitable conditions, so that operations like assignment to an element
of an array need not involve copying the entire array.
The initial application for this feature is arrays, but it is not hard
to foresee using it for other container types like JSON, XML and hstore.
I have hopes that it will be useful to PostGIS as well.
In this initial implementation, a few heuristics have been hard-wired
into plpgsql to improve performance for arrays that are stored in
plpgsql variables. We would like to generalize those hacks so that
other datatypes can obtain similar improvements, but figuring out some
appropriate APIs is left as a task for future work. (The heuristics
themselves are probably not optimal yet, either, as they sometimes
force expansion of arrays that would be better left alone.)
Preliminary performance testing shows impressive speed gains for plpgsql
functions that do element-by-element access or update of large arrays.
There are other cases that get a little slower, as a result of added array
format conversions; but we can hope to improve anything that's annoyingly
bad. In any case most applications should see a net win.
Tom Lane, reviewed by Andres Freund
2015-05-14 12:08:40 -04:00
|
|
|
}
|
|
|
|
|
it->bitmask <<= 1;
|
|
|
|
|
if (it->bitmask == 0x100)
|
|
|
|
|
{
|
|
|
|
|
if (it->bitmapptr)
|
|
|
|
|
it->bitmapptr++;
|
|
|
|
|
it->bitmask = 1;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
#endif /* ARRAYACCESS_H */
|
