Early return if common prefix isn't a prefix of an entry

For range reads
This commit is contained in:
2024-08-06 15:32:44 -07:00
parent d89028dd2f
commit 29c05187fb
+35 -1
View File
@@ -2785,6 +2785,8 @@ bool checkRangeRead(Node *n, std::span<const uint8_t> begin,
auto remaining = begin.subspan(0, lcp);
Arena arena;
// If the common prefix isn't a prefix of any physical entry in the tree, we
// can go to "downLeftSpine"
for (;; ++tls->range_read_iterations_accum) {
assert(getSearchPath(arena, n) <=>
begin.subspan(0, lcp - remaining.size()) ==
@@ -2794,12 +2796,38 @@ bool checkRangeRead(Node *n, std::span<const uint8_t> begin,
}
auto [child, v] = getChildAndMaxVersion(n, remaining[0]);
if (child == nullptr) {
break;
auto c = getChildGeq(n, remaining[0]);
if (c != nullptr) {
n = c;
goto downLeftSpine;
} else {
n = nextSibling(n);
if (n == nullptr) {
return true;
}
goto downLeftSpine;
}
}
if (child->partialKeyLen > 0) {
int cl = std::min<int>(child->partialKeyLen, remaining.size() - 1);
int i =
longestCommonPrefix(child->partialKey(), remaining.data() + 1, cl);
if (i < cl) {
auto c = child->partialKey()[i] <=> remaining[1 + i];
if (c > 0) {
n = child;
goto downLeftSpine;
} else {
n = nextSibling(child);
if (n == nullptr) {
return true;
}
goto downLeftSpine;
}
}
// If the partial key is longer than the common prefix (remaining), we
// still need to keep searching
if (i != child->partialKeyLen) {
break;
}
@@ -2815,6 +2843,12 @@ bool checkRangeRead(Node *n, std::span<const uint8_t> begin,
}
assert(getSearchPath(arena, n) <=> begin.subspan(0, lcp - remaining.size()) ==
0);
if (0) {
downLeftSpine:
for (; !n->entryPresent; n = getFirstChildExists(n)) {
}
return n->entry.rangeVersion <= readVersion;
}
const int consumed = lcp - remaining.size();
assume(consumed >= 0);