From 70bc5833195daf64a200ac7b4a8c9aff65cf966f Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 27 Sep 2012 16:59:59 -0400
Subject: [PATCH] Fix btmarkpos/btrestrpos to handle array keys.
This fixes another error in commit 9e8da0f75731aaa7605cf4656c21ea09e84d2eb1.
I neglected to make the mark/restore functionality save and restore the
current set of array key values, which led to strange behavior if an
IndexScan with ScalarArrayOpExpr quals was used as the inner side of a
mergejoin. Per bug #7570 from Melese Tesfaye.
---
src/backend/access/nbtree/nbtree.c | 8 ++++
src/backend/access/nbtree/nbtutils.c | 59 ++++++++++++++++++++++++++++
src/include/access/nbtree.h | 3 ++
3 files changed, 70 insertions(+)
diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c
index 0fd595a2d4e..b055eaff5b2 100644
--- a/src/backend/access/nbtree/nbtree.c
+++ b/src/backend/access/nbtree/nbtree.c
@@ -584,6 +584,10 @@ btmarkpos(PG_FUNCTION_ARGS)
else
so->markItemIndex = -1;
+ /* Also record the current positions of any array keys */
+ if (so->numArrayKeys)
+ _bt_mark_array_keys(scan);
+
PG_RETURN_VOID();
}
@@ -596,6 +600,10 @@ btrestrpos(PG_FUNCTION_ARGS)
IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0);
BTScanOpaque so = (BTScanOpaque) scan->opaque;
+ /* Restore the marked positions of any array keys */
+ if (so->numArrayKeys)
+ _bt_restore_array_keys(scan);
+
if (so->markItemIndex >= 0)
{
/*
diff --git a/src/backend/access/nbtree/nbtutils.c b/src/backend/access/nbtree/nbtutils.c
index 33ad8915f5a..50df5e0e5ba 100644
--- a/src/backend/access/nbtree/nbtutils.c
+++ b/src/backend/access/nbtree/nbtutils.c
@@ -595,6 +595,65 @@ _bt_advance_array_keys(IndexScanDesc scan, ScanDirection dir)
return found;
}
+/*
+ * _bt_mark_array_keys() -- Handle array keys during btmarkpos
+ *
+ * Save the current state of the array keys as the "mark" position.
+ */
+void
+_bt_mark_array_keys(IndexScanDesc scan)
+{
+ BTScanOpaque so = (BTScanOpaque) scan->opaque;
+ int i;
+
+ for (i = 0; i < so->numArrayKeys; i++)
+ {
+ BTArrayKeyInfo *curArrayKey = &so->arrayKeys[i];
+
+ curArrayKey->mark_elem = curArrayKey->cur_elem;
+ }
+}
+
+/*
+ * _bt_restore_array_keys() -- Handle array keys during btrestrpos
+ *
+ * Restore the array keys to where they were when the mark was set.
+ */
+void
+_bt_restore_array_keys(IndexScanDesc scan)
+{
+ BTScanOpaque so = (BTScanOpaque) scan->opaque;
+ bool changed = false;
+ int i;
+
+ /* Restore each array key to its position when the mark was set */
+ for (i = 0; i < so->numArrayKeys; i++)
+ {
+ BTArrayKeyInfo *curArrayKey = &so->arrayKeys[i];
+ ScanKey skey = &so->arrayKeyData[curArrayKey->scan_key];
+ int mark_elem = curArrayKey->mark_elem;
+
+ if (curArrayKey->cur_elem != mark_elem)
+ {
+ curArrayKey->cur_elem = mark_elem;
+ skey->sk_argument = curArrayKey->elem_values[mark_elem];
+ changed = true;
+ }
+ }
+
+ /*
+ * If we changed any keys, we must redo _bt_preprocess_keys. That might
+ * sound like overkill, but in cases with multiple keys per index column
+ * it seems necessary to do the full set of pushups.
+ */
+ if (changed)
+ {
+ _bt_preprocess_keys(scan);
+ /* The mark should have been set on a consistent set of keys... */
+ Assert(so->qual_ok);
+ }
+}
+
/*
* _bt_preprocess_keys() -- Preprocess scan keys
diff --git a/src/include/access/nbtree.h b/src/include/access/nbtree.h
index f23ac3559ad..d4941e0ff84 100644
--- a/src/include/access/nbtree.h
+++ b/src/include/access/nbtree.h
@@ -535,6 +535,7 @@ typedef struct BTArrayKeyInfo
{
int scan_key; /* index of associated key in arrayKeyData */
int cur_elem; /* index of current element in elem_values */
+ int mark_elem; /* index of marked element in elem_values */
int num_elems; /* number of elems in current array value */
Datum *elem_values; /* array of num_elems Datums */
} BTArrayKeyInfo;
@@ -665,6 +666,8 @@ extern void _bt_freestack(BTStack stack);
extern void _bt_preprocess_array_keys(IndexScanDesc scan);
extern void _bt_start_array_keys(IndexScanDesc scan, ScanDirection dir);
extern bool _bt_advance_array_keys(IndexScanDesc scan, ScanDirection dir);
+extern void _bt_mark_array_keys(IndexScanDesc scan);
+extern void _bt_restore_array_keys(IndexScanDesc scan);
extern void _bt_preprocess_keys(IndexScanDesc scan);
extern IndexTuple _bt_checkkeys(IndexScanDesc scan,
Page page, OffsetNumber offnum,
--
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