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Backup: do not write the index cache inside the read-only dump transaction

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A database dump that fills a whole pack (32 MiB) uploads that pack while
the dump transaction is still open, and the pack's index cache row was
inserted on the same connection. PostgreSQL refuses that (25006, read-only
transaction) and the run failed; on other databases the row was rolled
back with the dump transaction. The index now holds those cache writes
back until the transaction is over.
This commit is contained in:
Dillard Blom
2026-10-08 13:03:52 +02:00
parent bfd54447b0
commit 62766e1e71
4 changed files with 94 additions and 2 deletions
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tests/Unit/Repository/IndexCacheTest.php
+37
View File
@@ -51,4 +51,41 @@ class IndexCacheTest extends TestCase {
$fourth->restore($r1['snapshot'], $target);
$this->assertCount(12, self::hashTree($target));
}
/** The database dump reads in a read-only transaction: a pack that fills up then must not write the cache yet. */
public function testHeldCacheWritesWaitForRelease(): void {
$cache = new class implements IIndexCache {
public array $data = [];
public bool $readOnly = false;
public function all(string $r): array { return $this->data[$r] ?? []; }
public function put(string $r, string $p, array $e): void {
if ($this->readOnly) {
throw new \RuntimeException('cannot execute INSERT in a read-only transaction');
}
$this->data[$r][$p] = $e;
}
public function remove(string $r, array $ps): void { foreach ($ps as $p) { unset($this->data[$r][$p]); } }
};
$backend = new LocalBackend($this->tempDir());
$keys = KeyRing::generate();
Repository::initWithKey($backend, $keys, $keys->wrap('pw'));
$repo = Repository::openWithKey($backend, $keys, $cache);
$stats = [];
$repo->holdIndexCache();
$cache->readOnly = true;
$writer = $repo->blobWriter($stats);
for ($i = 0; $i < 40; $i++) {
$writer->write(random_bytes(1048576)); // more than one 32 MiB pack
}
$writer->finish();
$this->assertGreaterThan(0, count($backend->list('index')), 'a full pack was uploaded during the hold');
$this->assertSame([], $cache->data);
$cache->readOnly = false;
$repo->releaseIndexCache();
$repo->flushPacks();
$this->assertCount(count($backend->list('index')), array_merge(...array_values($cache->data)));
$this->assertSame(0, Repository::openWithKey($backend, $keys, $cache)->indexDownloads());
}
}