Change ginMergeItemPointers to return a palloc'd array.

That seems nicer than making it the caller's responsibility to pass a
suitable-sized array. All the callers were just palloc'ing an array anyway.

diff --git a/src/backend/access/gin/gindatapage.c b/src/backend/access/gin/gindatapage.c
index c6230f3bc5a433a408a7290ba72900a9f5aa354b..313d53c354fa9d6a0e2e54073e2eda1a4fe2f412 100644 (file)
--- a/src/backend/access/gin/gindatapage.c
+++ b/src/backend/access/gin/gindatapage.c
@@ -1303,10 +1303,9 @@ addItemsToLeaf(disassembledLeaf *leaf, ItemPointer newItems, int nNewItems)
        if (!cur->items)
            cur->items = ginPostingListDecode(cur->seg, &cur->nitems);
 
-       tmpitems = palloc((cur->nitems + nthis) * sizeof(ItemPointerData));
-       ntmpitems = ginMergeItemPointers(tmpitems,
-                                        cur->items, cur->nitems,
-                                        nextnew, nthis);
+       tmpitems = ginMergeItemPointers(cur->items, cur->nitems,
+                                       nextnew, nthis,
+                                       &ntmpitems);
        if (ntmpitems != cur->nitems)
        {
            cur->items = tmpitems;

diff --git a/src/backend/access/gin/gininsert.c b/src/backend/access/gin/gininsert.c
index cd9c7c120b334528e7ecbad76b384b893c85f66c..3bafb6471b337aa9394dbdcaa662e0e2e8f6a483 100644 (file)
--- a/src/backend/access/gin/gininsert.c
+++ b/src/backend/access/gin/gininsert.c
@@ -67,12 +67,9 @@ addItemPointersToLeafTuple(GinState *ginstate,
    /* merge the old and new posting lists */
    oldItems = ginReadTuple(ginstate, attnum, old, &oldNPosting);
 
-   newNPosting = oldNPosting + nitem;
-   newItems = (ItemPointerData *) palloc(sizeof(ItemPointerData) * newNPosting);
-
-   newNPosting = ginMergeItemPointers(newItems,
-                                      items, nitem,
-                                      oldItems, oldNPosting);
+   newItems = ginMergeItemPointers(items, nitem,
+                                   oldItems, oldNPosting,
+                                   &newNPosting);
 
    /* Compress the posting list, and try to a build tuple with room for it */
    res = NULL;

diff --git a/src/backend/access/gin/ginpostinglist.c b/src/backend/access/gin/ginpostinglist.c
index f532a3dbf032269c5d7dc512686b5a5228c79d62..4c4110d54b1666ff3a397514ad9fe1006dee2d73 100644 (file)
--- a/src/backend/access/gin/ginpostinglist.c
+++ b/src/backend/access/gin/ginpostinglist.c
@@ -346,20 +346,18 @@ ginPostingListDecodeAllSegmentsToTbm(GinPostingList *ptr, int len,
 
 /*
  * Merge two ordered arrays of itempointers, eliminating any duplicates.
- * Returns the number of items in the result.
- * Caller is responsible that there is enough space at *dst.
  *
- * It's OK if 'dst' overlaps with the *beginning* of one of the arguments.
+ * Returns a palloc'd array, and *nmerged is set to the number of items in
+ * the result, after eliminating duplicates.
  */
-int
-ginMergeItemPointers(ItemPointerData *dst,
-                    ItemPointerData *a, uint32 na,
-                    ItemPointerData *b, uint32 nb)
+ItemPointer
+ginMergeItemPointers(ItemPointerData *a, uint32 na,
+                    ItemPointerData *b, uint32 nb,
+                    int *nmerged)
 {
-   ItemPointerData *dptr = dst;
-   ItemPointerData *aptr = a,
-              *bptr = b;
-   int         result;
+   ItemPointerData *dst;
+
+   dst = (ItemPointer) palloc((na + nb) * sizeof(ItemPointerData));
 
    /*
     * If the argument arrays don't overlap, we can just append them to
@@ -367,18 +365,22 @@ ginMergeItemPointers(ItemPointerData *dst,
     */
    if (na == 0 || nb == 0 || ginCompareItemPointers(&a[na - 1], &b[0]) < 0)
    {
-       memmove(dst, a, na * sizeof(ItemPointerData));
-       memmove(&dst[na], b, nb * sizeof(ItemPointerData));
-       result = na + nb;
+       memcpy(dst, a, na * sizeof(ItemPointerData));
+       memcpy(&dst[na], b, nb * sizeof(ItemPointerData));
+       *nmerged = na + nb;
    }
    else if (ginCompareItemPointers(&b[nb - 1], &a[0]) < 0)
    {
-       memmove(dst, b, nb * sizeof(ItemPointerData));
-       memmove(&dst[nb], a, na * sizeof(ItemPointerData));
-       result = na + nb;
+       memcpy(dst, b, nb * sizeof(ItemPointerData));
+       memcpy(&dst[nb], a, na * sizeof(ItemPointerData));
+       *nmerged = na + nb;
    }
    else
    {
+       ItemPointerData *dptr = dst;
+       ItemPointerData *aptr = a;
+       ItemPointerData *bptr = b;
+
        while (aptr - a < na && bptr - b < nb)
        {
            int         cmp = ginCompareItemPointers(aptr, bptr);
@@ -401,8 +403,8 @@ ginMergeItemPointers(ItemPointerData *dst,
        while (bptr - b < nb)
            *dptr++ = *bptr++;
 
-       result = dptr - dst;
+       *nmerged = dptr - dst;
    }
 
-   return result;
+   return dst;
 }

diff --git a/src/include/access/gin_private.h b/src/include/access/gin_private.h
index 009927282f5339185eaf65a9302de13cf09a6f3c..a7beed1f256cbd314b7abb262ced4518b965b951 100644 (file)
--- a/src/include/access/gin_private.h
+++ b/src/include/access/gin_private.h
@@ -919,9 +919,9 @@ extern int ginPostingListDecodeAllSegmentsToTbm(GinPostingList *ptr, int totalsi
 
 extern ItemPointer ginPostingListDecodeAllSegments(GinPostingList *ptr, int len, int *ndecoded);
 extern ItemPointer ginPostingListDecode(GinPostingList *ptr, int *ndecoded);
-extern int ginMergeItemPointers(ItemPointerData *dst,
-                    ItemPointerData *a, uint32 na,
-                    ItemPointerData *b, uint32 nb);
+extern ItemPointer ginMergeItemPointers(ItemPointerData *a, uint32 na,
+                    ItemPointerData *b, uint32 nb,
+                    int *nmerged);
 
 /*
  * Merging the results of several gin scans compares item pointers a lot,