checkRangeLeftSide

This commit is contained in:
2024-09-04 12:11:16 -07:00
parent 6fe6a244af
commit 2037d37c66

View File

@@ -2510,24 +2510,22 @@ downLeftSpine:
namespace { namespace {
// Return true if the max version among all keys that start with key[:prefixLen] // Return true if the max version among all keys that start with key[:prefixLen]
// that are >= key is <= readVersion // that are >= key is <= readVersion
struct CheckRangeLeftSide { bool checkRangeLeftSide(Node *n, std::span<const uint8_t> key, int prefixLen,
bool ok;
bool step(Node *n, std::span<const uint8_t> key, int prefixLen,
InternalVersionT readVersion, ReadContext *tls) { InternalVersionT readVersion, ReadContext *tls) {
bool ok;
auto remaining = key; auto remaining = key;
int searchPathLen = 0; int searchPathLen = 0;
for (;; ++tls->range_read_iterations_accum) { for (;; ++tls->range_read_iterations_accum) {
if (remaining.size() == 0) { if (remaining.size() == 0) {
assert(searchPathLen >= prefixLen); assert(searchPathLen >= prefixLen);
ok = maxVersion(n) <= readVersion; ok = maxVersion(n) <= readVersion;
return true; return ok;
} }
if (searchPathLen >= prefixLen) { if (searchPathLen >= prefixLen) {
if (!checkMaxBetweenExclusive(n, remaining[0], 256, readVersion, tls)) { if (!checkMaxBetweenExclusive(n, remaining[0], 256, readVersion, tls)) {
ok = false; ok = false;
return true; return ok;
} }
} }
@@ -2541,12 +2539,12 @@ struct CheckRangeLeftSide {
} }
n = c; n = c;
ok = maxVersion(n) <= readVersion; ok = maxVersion(n) <= readVersion;
return true; return ok;
} else { } else {
n = nextSibling(n); n = nextSibling(n);
if (n == nullptr) { if (n == nullptr) {
ok = true; ok = true;
return true; return ok;
} }
goto downLeftSpine; goto downLeftSpine;
} }
@@ -2558,8 +2556,7 @@ struct CheckRangeLeftSide {
if (n->partialKeyLen > 0) { if (n->partialKeyLen > 0) {
int commonLen = std::min<int>(n->partialKeyLen, remaining.size()); int commonLen = std::min<int>(n->partialKeyLen, remaining.size());
int i = int i = longestCommonPrefix(n->partialKey(), remaining.data(), commonLen);
longestCommonPrefix(n->partialKey(), remaining.data(), commonLen);
searchPathLen += i; searchPathLen += i;
if (i < commonLen) { if (i < commonLen) {
auto c = n->partialKey()[i] <=> remaining[i]; auto c = n->partialKey()[i] <=> remaining[i];
@@ -2569,45 +2566,43 @@ struct CheckRangeLeftSide {
} }
if (n->entryPresent && n->entry.rangeVersion > readVersion) { if (n->entryPresent && n->entry.rangeVersion > readVersion) {
ok = false; ok = false;
return true; return ok;
} }
ok = maxVersion(n) <= readVersion; ok = maxVersion(n) <= readVersion;
return true; return ok;
} else { } else {
n = nextSibling(n); n = nextSibling(n);
if (n == nullptr) { if (n == nullptr) {
ok = true; ok = true;
return true; return ok;
} }
goto downLeftSpine; goto downLeftSpine;
} }
} }
if (commonLen == n->partialKeyLen) { if (commonLen == n->partialKeyLen) {
// partial key matches // partial key matches
remaining = remaining = remaining.subspan(commonLen, remaining.size() - commonLen);
remaining.subspan(commonLen, remaining.size() - commonLen);
} else if (n->partialKeyLen > int(remaining.size())) { } else if (n->partialKeyLen > int(remaining.size())) {
assert(searchPathLen >= prefixLen); assert(searchPathLen >= prefixLen);
if (n->entryPresent && n->entry.rangeVersion > readVersion) { if (n->entryPresent && n->entry.rangeVersion > readVersion) {
ok = false; ok = false;
return true; return ok;
} }
ok = maxVersion(n) <= readVersion; ok = maxVersion(n) <= readVersion;
return true; return ok;
} }
} }
if (maxV <= readVersion) { if (maxV <= readVersion) {
ok = true; ok = true;
return true; return ok;
} }
} }
downLeftSpine: downLeftSpine:
for (; !n->entryPresent; n = getFirstChildExists(n)) { for (; !n->entryPresent; n = getFirstChildExists(n)) {
} }
ok = n->entry.rangeVersion <= readVersion; ok = n->entry.rangeVersion <= readVersion;
return true; return ok;
} }
};
// Return true if the max version among all keys that start with key[:prefixLen] // Return true if the max version among all keys that start with key[:prefixLen]
// that are < key is <= readVersion // that are < key is <= readVersion
@@ -2816,13 +2811,12 @@ bool checkRangeRead(Node *n, std::span<const uint8_t> begin,
// This makes it safe to check maxVersion within CheckRangeLeftSide. If this // This makes it safe to check maxVersion within CheckRangeLeftSide. If this
// were false, then we would have returned above since lcp == begin.size(). // were false, then we would have returned above since lcp == begin.size().
assert(!(n->parent == nullptr && begin.size() == 0)); assert(!(n->parent == nullptr && begin.size() == 0));
CheckRangeLeftSide checkRangeLeftSide{}; bool lhsOk = checkRangeLeftSide(n, begin, lcp + 1, readVersion, tls);
checkRangeLeftSide.step(n, begin, lcp + 1, readVersion, tls);
CheckRangeRightSide checkRangeRightSide{n, end, lcp + 1, readVersion, tls}; CheckRangeRightSide checkRangeRightSide{n, end, lcp + 1, readVersion, tls};
for (; !checkRangeRightSide.step(); ++tls->range_read_iterations_accum) for (; !checkRangeRightSide.step(); ++tls->range_read_iterations_accum)
; ;
return checkRangeLeftSide.ok && checkRangeRightSide.ok; return lhsOk && checkRangeRightSide.ok;
} }
#ifdef __x86_64__ #ifdef __x86_64__