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NarInfoDiskCache: Keep BinaryCache.id stable and improve test

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Fixes #3898

The entire `BinaryCaches` row used to get replaced after it became
stale according to the `timestamp` column. In a concurrent scenario,
this leads to foreign key conflicts as different instances of the
in-process `state.caches` cache now differ, with the consequence that
the older process still tries to use the `id` number of the old record.

Furthermore, this phenomenon appears to have caused the cache for
actual narinfos to be erased about every week, while the default
ttl for narinfos was supposed to be 30 days.
This commit is contained in:
Robert Hensing 2023-01-17 19:56:06 +01:00
parent 2ceece3ef3
commit fb94d5cabd
3 changed files with 73 additions and 36 deletions
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38
src/libstore/nar-info-disk-cache.cc
View file

@ -97,7 +97,7 @@ public:
state->db.exec(schema);
state->insertCache.create(state->db,
"insert or replace into BinaryCaches(url, timestamp, storeDir, wantMassQuery, priority) values (?, ?, ?, ?, ?)");
"insert into BinaryCaches(url, timestamp, storeDir, wantMassQuery, priority) values (?1, ?2, ?3, ?4, ?5) on conflict (url) do update set timestamp = ?2, storeDir = ?3, wantMassQuery = ?4, priority = ?5 returning id;");
state->queryCache.create(state->db,
"select id, storeDir, wantMassQuery, priority from BinaryCaches where url = ? and timestamp > ?");
@ -165,6 +165,8 @@ public:
return i->second;
}
private:
std::optional<Cache> queryCacheRaw(State & state, const std::string & uri)
{
auto i = state.caches.find(uri);
@ -172,15 +174,21 @@ public:
auto queryCache(state.queryCache.use()(uri)(time(0) - cacheInfoTtl));
if (!queryCache.next())
return std::nullopt;
state.caches.emplace(uri,
Cache{(int) queryCache.getInt(0), queryCache.getStr(1), queryCache.getInt(2) != 0, (int) queryCache.getInt(3)});
auto cache = Cache {
.id = (int) queryCache.getInt(0),
.storeDir = queryCache.getStr(1),
.wantMassQuery = queryCache.getInt(2) != 0,
.priority = (int) queryCache.getInt(3),
};
state.caches.emplace(uri, cache);
}
return getCache(state, uri);
}
void createCache(const std::string & uri, const Path & storeDir, bool wantMassQuery, int priority) override
public:
int createCache(const std::string & uri, const Path & storeDir, bool wantMassQuery, int priority) override
{
retrySQLite<void>([&]() {
return retrySQLite<int>([&]() {
auto state(_state.lock());
SQLiteTxn txn(state->db);
@ -189,13 +197,25 @@ public:
auto cache(queryCacheRaw(*state, uri));
if (cache)
return;
return cache->id;
state->insertCache.use()(uri)(time(0))(storeDir)(wantMassQuery)(priority).exec();
assert(sqlite3_changes(state->db) == 1);
state->caches[uri] = Cache{(int) sqlite3_last_insert_rowid(state->db), storeDir, wantMassQuery, priority};
Cache ret {
.id = -1, // set below
.storeDir = storeDir,
.wantMassQuery = wantMassQuery,
.priority = priority,
};
{
auto r(state->insertCache.use()(uri)(time(0))(storeDir)(wantMassQuery)(priority));
assert(r.next());
ret.id = (int) r.getInt(0);
}
state->caches[uri] = ret;
txn.commit();
return ret.id;
});
}