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Eliminate a few HnswPtrAccess invocations

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HnswPtrAccess() is pretty cheap, but it stills seems worthwhile to
avoid repeated calls in the hot paths when it can be easily avoided.
This commit is contained in:
Heikki Linnakangas
2024-02-19 14:09:32 +02:00
parent 1cbd204f52
commit 334c386a45
1 changed files with 20 additions and 24 deletions
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44
src/hnswutils.c
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@@ -559,13 +559,12 @@ HnswLoadElement(HnswElement element, float *distance, Datum *q, Relation index,
}
/*
* Get the distance for a candidate
* Get the distance between 'hc' and 'q'
*/
static float
GetCandidateDistance(char *base, HnswCandidate * hc, Datum q, FmgrInfo *procinfo, Oid collation)
GetElementDistance(char *base, HnswElement hc, Datum q, FmgrInfo *procinfo, Oid collation)
{
HnswElement hce = HnswPtrAccess(base, hc->element);
Datum value = HnswGetValue(base, hce);
Datum value = HnswGetValue(base, hc);
return DatumGetFloat8(FunctionCall2Coll(procinfo, collation, q, value));
}
@@ -580,7 +579,7 @@ HnswEntryCandidate(char *base, HnswElement entryPoint, Datum q, Relation index,
HnswPtrStore(base, hc->element, entryPoint);
if (index == NULL)
hc->distance = GetCandidateDistance(base, hc, q, procinfo, collation);
hc->distance = GetElementDistance(base, entryPoint, q, procinfo, collation);
else
HnswLoadElement(entryPoint, &hc->distance, &q, index, procinfo, collation, loadVec);
return hc;
@@ -667,17 +666,14 @@ AddToVisited(char *base, visited_hash * v, HnswElement element, Relation index,
* Count element towards ef
*/
static inline bool
CountElement(char *base, HnswElement skipElement, HnswCandidate * hc)
CountElement(char *base, HnswElement skipElement, HnswElement e)
{
HnswElement e;
if (skipElement == NULL)
return true;
/* Ensure does not access heaptidsLength during in-memory build */
pg_memory_barrier();
e = HnswPtrAccess(base, hc->element);
return e->heaptidsLength != 0;
}
@@ -709,9 +705,10 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
foreach(lc2, ep)
{
HnswCandidate *hc = (HnswCandidate *) lfirst(lc2);
HnswElement e = HnswPtrAccess(base, hc->element);
bool found;
AddToVisited(base, &v, HnswPtrAccess(base, hc->element), index, &found);
AddToVisited(base, &v, e, index, &found);
pairingheap_add(C, &(CreatePairingHeapNode(hc)->ph_node));
pairingheap_add(W, &(CreatePairingHeapNode(hc)->ph_node));
@@ -721,7 +718,7 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
* would be ideal to do this for inserts as well, but this could
* affect insert performance.
*/
if (CountElement(base, skipElement, hc))
if (CountElement(base, skipElement, e))
wlen++;
}
@@ -754,8 +751,8 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
for (int i = 0; i < neighborhood->length; i++)
{
HnswCandidate *e = &neighborhood->items[i];
HnswElement eElement = HnswPtrAccess(base, e->element);
HnswCandidate *hc = &neighborhood->items[i];
HnswElement eElement = HnswPtrAccess(base, hc->element);
bool visited;
AddToVisited(base, &v, eElement, index, &visited);
@@ -767,7 +764,7 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
f = ((HnswPairingHeapNode *) pairingheap_first(W))->inner;
if (index == NULL)
eDistance = GetCandidateDistance(base, e, q, procinfo, collation);
eDistance = GetElementDistance(base, eElement, q, procinfo, collation);
else
HnswLoadElement(eElement, &eDistance, &q, index, procinfo, collation, inserting);
@@ -782,7 +779,7 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
/* Copy e */
HnswCandidate *ec = palloc(sizeof(HnswCandidate));
HnswPtrStore(base, ec->element, eElement);
ec->element = hc->element;
ec->distance = eDistance;
pairingheap_add(C, &(CreatePairingHeapNode(ec)->ph_node));
@@ -793,7 +790,7 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
* vacuuming. It would be ideal to do this for inserts as
* well, but this could affect insert performance.
*/
if (CountElement(base, skipElement, e))
if (CountElement(base, skipElement, eElement))
{
wlen++;
@@ -874,15 +871,12 @@ CompareCandidateDistancesOffset(const void *a, const void *b)
}
/*
* Calculate the distance between elements
* Calculate the distance between two vectors
*/
static float
HnswGetDistance(char *base, HnswElement a, HnswElement b, FmgrInfo *procinfo, Oid collation)
HnswGetDistance(Datum a, Datum b, FmgrInfo *procinfo, Oid collation)
{
Datum aValue = HnswGetValue(base, a);
Datum bValue = HnswGetValue(base, b);
return DatumGetFloat8(FunctionCall2Coll(procinfo, collation, aValue, bValue));
return DatumGetFloat8(FunctionCall2Coll(procinfo, collation, a, b));
}
/*
@@ -892,13 +886,15 @@ static bool
CheckElementCloser(char *base, HnswCandidate * e, List *r, FmgrInfo *procinfo, Oid collation)
{
HnswElement eElement = HnswPtrAccess(base, e->element);
Datum eValue = HnswGetValue(base, eElement);
ListCell *lc2;
foreach(lc2, r)
{
HnswCandidate *ri = lfirst(lc2);
HnswElement riElement = HnswPtrAccess(base, ri->element);
float distance = HnswGetDistance(base, eElement, riElement, procinfo, collation);
Datum riValue = HnswGetValue(base, riElement);
float distance = HnswGetDistance(eValue, riValue, procinfo, collation);
if (distance <= e->distance)
return false;
@@ -1064,7 +1060,7 @@ HnswUpdateConnection(char *base, HnswElement element, HnswCandidate * hc, int lm
if (HnswPtrIsNull(base, hc3Element->value))
HnswLoadElement(hc3Element, &hc3->distance, &q, index, procinfo, collation, true);
else
hc3->distance = GetCandidateDistance(base, hc3, q, procinfo, collation);
hc3->distance = GetElementDistance(base, hc3Element, q, procinfo, collation);
/* Prune element if being deleted */
if (hc3Element->heaptidsLength == 0)