From 6aa2bdf6a01ce099e315cb313396ca4b8415321b Mon Sep 17 00:00:00 2001 From: Heikki Linnakangas Date: Fri, 7 Feb 2014 18:41:01 +0200 Subject: [PATCH] Initialize the entryRes array between each call to triConsistent. The shimTriConstistentFn, which calls the opclass's consistent function with all combinations of TRUE/FALSE for any MAYBE argument, modifies the entryRes array passed by the caller. Change startScanKey to re-initialize it between each call to accommodate that. It's actually a bad habit by shimTriConsistentFn to modify its argument. But the only caller that doesn't already re-initialize the entryRes array was startScanKey, and it's easy for startScanKey to do so. Add a comment to shimTriConsistentFn about that. Note: this does not give a free pass to opclass-provided consistent functions to modify the entryRes argument; shimTriConsistent assumes that they don't, even though it does it itself. While at it, refactor startScanKey to allocate the requiredEntries and additionalEntries after it knows exactly how large they need to be. Saves a little bit of memory, and looks nicer anyway. Per complaint by Tom Lane, buildfarm and the pg_trgm regression test. --- src/backend/access/gin/ginget.c | 40 +++++++++++++++++++------------ src/backend/access/gin/ginlogic.c | 6 +++-- 2 files changed, 29 insertions(+), 17 deletions(-) diff --git a/src/backend/access/gin/ginget.c b/src/backend/access/gin/ginget.c index 1cb66d30a7..e24ff180a7 100644 --- a/src/backend/access/gin/ginget.c +++ b/src/backend/access/gin/ginget.c @@ -445,6 +445,7 @@ startScanKey(GinState *ginstate, GinScanOpaque so, GinScanKey key) { MemoryContext oldCtx = CurrentMemoryContext; int i; + int j; int *entryIndexes; ItemPointerSetMin(&key->curItem); @@ -472,10 +473,6 @@ startScanKey(GinState *ginstate, GinScanOpaque so, GinScanKey key) * entries can form a match, without any items from the required set. The * rest go to the additional set. */ - key->requiredEntries = palloc(key->nentries * sizeof(GinScanEntry)); - key->additionalEntries = palloc(key->nentries * sizeof(GinScanEntry)); - key->nrequired = key->nadditional = 0; - if (key->nentries > 1) { MemoryContextSwitchTo(so->tempCtx); @@ -483,31 +480,44 @@ startScanKey(GinState *ginstate, GinScanOpaque so, GinScanKey key) entryIndexes = (int *) palloc(sizeof(int) * key->nentries); for (i = 0; i < key->nentries; i++) entryIndexes[i] = i; - qsort_arg(entryIndexes, key->nentries, sizeof(int), entryIndexByFrequencyCmp, key); - for (i = 0; i < key->nentries; i++) - key->entryRes[i] = GIN_MAYBE; - - for (i = 0; i < key->nentries; i++) + for (i = 0; i < key->nentries - 1; i++) { - key->requiredEntries[key->nrequired++] = key->scanEntry[entryIndexes[i]]; - key->entryRes[entryIndexes[i]] = GIN_FALSE; + /* Pass all entries <= i as FALSE, and the rest as MAYBE */ + for (j = 0; j <= i; j++) + key->entryRes[entryIndexes[j]] = GIN_FALSE; + for (j = i + 1; j < key->nentries; j++) + key->entryRes[entryIndexes[j]] = GIN_MAYBE; if (key->triConsistentFn(key) == GIN_FALSE) break; } - for (i = i + 1; i < key->nentries; i++) - key->additionalEntries[key->nadditional++] = key->scanEntry[entryIndexes[i]]; + /* i is now the last required entry. */ - /* clean up after consistentFn calls (also frees entryIndexes) */ MemoryContextSwitchTo(oldCtx); + + key->nrequired = i + 1; + key->nadditional = key->nentries - key->nrequired; + key->requiredEntries = palloc(key->nrequired * sizeof(GinScanEntry)); + key->additionalEntries = palloc(key->nadditional * sizeof(GinScanEntry)); + + j = 0; + for (i = 0; i < key->nrequired; i++) + key->requiredEntries[i] = key->scanEntry[entryIndexes[j++]]; + for (i = 0; i < key->nadditional; i++) + key->additionalEntries[i] = key->scanEntry[entryIndexes[j++]]; + + /* clean up after consistentFn calls (also frees entryIndexes) */ MemoryContextReset(so->tempCtx); } else { - key->requiredEntries[key->nrequired++] = key->scanEntry[0]; + key->nrequired = 1; + key->nadditional = 0; + key->requiredEntries = palloc(1 * sizeof(GinScanEntry)); + key->requiredEntries[0] = key->scanEntry[0]; } } diff --git a/src/backend/access/gin/ginlogic.c b/src/backend/access/gin/ginlogic.c index fb247446a2..dc8e6304a2 100644 --- a/src/backend/access/gin/ginlogic.c +++ b/src/backend/access/gin/ginlogic.c @@ -90,6 +90,8 @@ normalBoolConsistentFn(GinScanKey key) * combination, that's the overall result. Otherwise, return MAYBE. Testing * every combination is O(n^2), so this is only feasible for a small number of * MAYBE inputs. + * + * NB: This function modifies the key->entryRes array! */ static GinLogicValue shimTriConsistentFn(GinScanKey key) @@ -98,7 +100,7 @@ shimTriConsistentFn(GinScanKey key) int maybeEntries[MAX_MAYBE_ENTRIES]; int i; bool boolResult; - bool recheck = 0; + bool recheck = false; GinLogicValue curResult; /* @@ -124,7 +126,7 @@ shimTriConsistentFn(GinScanKey key) if (nmaybe == 0) return normalBoolConsistentFn(key); - /* Try the consistent function with the maybe-inputs set both ways */ + /* First call consistent function with all the maybe-inputs set FALSE */ for (i = 0; i < nmaybe; i++) key->entryRes[maybeEntries[i]] = GIN_FALSE; curResult = normalBoolConsistentFn(key); -- GitLab