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Refactor setting attributes in Arrow getsomeattrs()

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When populating an Arrow slot's tts_values array with values in the
getsomeattrs() function, the function set_attr_value() is called. This
function requires passing in an ArrowArray which is acquired via a
compression cache lookup. However, that lookup is not necassary for
segmentby columns (which aren't compressed) and, to avoid it, a
special fast-path was created for segmentby columns outside
set_attr_value(). That, unfortunately, created som code duplication.

This change moves the cache lookup into set_attr_value() instead,
where it can be performed only for the columns that need it. This
leads to cleaner code and less code duplication.
This commit is contained in:
Erik Nordström 2024-09-05 14:29:39 +02:00 committed by Mats Kindahl
parent e73d0ceb04
commit ea31d4f5c2
2 changed files with 38 additions and 63 deletions
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2
tsl/src/hyperstore/arrow_cache.c
View File

@ -314,7 +314,7 @@ arrow_cache_get_entry(ArrowTupleTableSlot *aslot)
* are actually referenced in a query), so some returned arrays may be NULL
* for this reason.
*/
pg_attribute_always_inline ArrowArray **
ArrowArray **
arrow_column_cache_read_one(ArrowTupleTableSlot *aslot, AttrNumber attno)
{
const int16 *attrs_offset_map = arrow_slot_get_attribute_offset_map(&aslot->base.base);

99
tsl/src/hyperstore/arrow_tts.c
View File

@ -446,32 +446,20 @@ is_compressed_col(const TupleDesc tupdesc, AttrNumber attno)
return coltypid == typinfo->type_oid;
}
static void
set_attr_value(TupleTableSlot *slot, ArrowArray **arrow_arrays, const AttrNumber attnum)
static pg_attribute_always_inline ArrowArray *
set_attr_value(TupleTableSlot *slot, const int16 attoff)
{
ArrowTupleTableSlot *aslot = (ArrowTupleTableSlot *) slot;
const int16 *attrs_offset_map = arrow_slot_get_attribute_offset_map(slot);
const int16 attoff = AttrNumberGetAttrOffset(attnum);
ArrowArray *arrow_array = NULL;
TS_DEBUG_LOG("attnum: %d, valid: %s, segmentby: %s, array: %s",
attnum,
TS_DEBUG_LOG("attnum: %d, valid: %s, segmentby: %s",
AttrOffsetGetAttrNumber(attoff),
yes_no(aslot->valid_attrs[attoff]),
yes_no(aslot->segmentby_attrs[attoff]),
yes_no(arrow_arrays[attoff]));
/* Check if value is already set */
if (aslot->valid_attrs[attoff])
return;
/* Nothing to do for dropped attribute */
if (attrs_offset_map[attoff] == -1)
{
Assert(TupleDescAttr(slot->tts_tupleDescriptor, attoff)->attisdropped);
return;
}
yes_no(aslot->segmentby_attrs[attoff]));
if (aslot->segmentby_attrs[attoff])
{
const int16 *attrs_offset_map = arrow_slot_get_attribute_offset_map(slot);
const int16 cattoff = attrs_offset_map[attoff]; /* offset in compressed tuple */
const AttrNumber cattnum = AttrOffsetGetAttrNumber(cattoff);
@ -480,27 +468,37 @@ set_attr_value(TupleTableSlot *slot, ArrowArray **arrow_arrays, const AttrNumber
slot->tts_values[attoff] =
slot_getattr(aslot->child_slot, cattnum, &slot->tts_isnull[attoff]);
}
else if (arrow_arrays[attoff] == NULL)
{
/* Since the column is not the segment-by column, and there is no
* decompressed data, the column must be NULL. Use the default
* value. */
slot->tts_values[attoff] =
getmissingattr(slot->tts_tupleDescriptor, attnum, &slot->tts_isnull[attoff]);
}
else
{
/* Value is compressed, so get it from the decompressed arrow array. */
const Form_pg_attribute attr = TupleDescAttr(slot->tts_tupleDescriptor, attoff);
const Oid typid = attr->atttypid;
const int16 typlen = attr->attlen;
const NullableDatum datum =
arrow_get_datum(arrow_arrays[attoff], typid, typlen, aslot->tuple_index - 1);
slot->tts_values[attoff] = datum.value;
slot->tts_isnull[attoff] = datum.isnull;
const AttrNumber attnum = AttrOffsetGetAttrNumber(attoff);
ArrowArray **arrow_arrays = arrow_column_cache_read_one(aslot, attnum);
arrow_array = arrow_arrays[attoff];
if (arrow_array == NULL)
{
/* Since the column is not the segment-by column, and there is no
* decompressed data, the column must be NULL. Use the default
* value. */
slot->tts_values[attoff] =
getmissingattr(slot->tts_tupleDescriptor, attnum, &slot->tts_isnull[attoff]);
}
else
{
/* Value is compressed, so get it from the decompressed arrow array. */
const Form_pg_attribute attr = TupleDescAttr(slot->tts_tupleDescriptor, attoff);
const Oid typid = attr->atttypid;
const int16 typlen = attr->attlen;
const NullableDatum datum =
arrow_get_datum(arrow_arrays[attoff], typid, typlen, aslot->tuple_index - 1);
slot->tts_values[attoff] = datum.value;
slot->tts_isnull[attoff] = datum.isnull;
}
}
aslot->valid_attrs[attoff] = true;
return arrow_array;
}
static inline bool
@ -545,30 +543,8 @@ tts_arrow_getsomeattrs(TupleTableSlot *slot, int natts)
/* Build the non-compressed tuple values array from the cached data. */
for (int attoff = slot->tts_nvalid; attoff < natts; attoff++)
{
const AttrNumber attno = AttrOffsetGetAttrNumber(attoff);
if (!aslot->valid_attrs[attoff])
{
/* Check if we can do a fast path for segmentby values and avoid a
* decompression cache lookup */
if (aslot->segmentby_attrs[attoff])
{
const int16 *attrs_offset_map = arrow_slot_get_attribute_offset_map(slot);
const int16 cattoff = attrs_offset_map[attoff]; /* offset in compressed tuple */
const AttrNumber cattnum = AttrOffsetGetAttrNumber(cattoff);
/* Segment-by column. Value is not compressed so get directly from
* child slot. */
slot->tts_values[attoff] =
slot_getattr(aslot->child_slot, cattnum, &slot->tts_isnull[attoff]);
aslot->valid_attrs[attoff] = true;
}
else if (is_used_attr(slot, attoff))
{
ArrowArray **arrow_arrays = arrow_column_cache_read_one(aslot, attno);
set_attr_value(slot, arrow_arrays, attno);
}
}
if (!aslot->valid_attrs[attoff] && is_used_attr(slot, attoff))
set_attr_value(slot, attoff);
}
slot->tts_nvalid = natts;
@ -787,11 +763,10 @@ arrow_slot_get_array(TupleTableSlot *slot, AttrNumber attno)
if (!is_used_attr(slot, attoff))
return NULL;
arrow_arrays = arrow_column_cache_read_one(aslot, attno);
if (!aslot->valid_attrs[attoff])
set_attr_value(slot, arrow_arrays, attno);
return set_attr_value(slot, attoff);
arrow_arrays = arrow_column_cache_read_one(aslot, attno);
return arrow_arrays[attoff];
}