1// Copyright (c) 2021-present The Bitcoin Core developers
2// Distributed under the MIT software license, see the accompanying
3// file COPYING or http://www.opensource.org/licenses/mit-license.php.
4
5#include <node/caches.h>
6
7#include <common/args.h>
8#include <common/system.h>
9#include <index/txindex.h>
10#include <index/txospenderindex.h>
11#include <kernel/caches.h>
12#include <node/interface_ui.h>
13#include <tinyformat.h>
14#include <util/byte_units.h>
15#include <util/log.h>
16#include <util/overflow.h>
17#include <util/translation.h>
18
19#include <algorithm>
20#include <cstdint>
21#include <string>
22
23// Unlike for the UTXO database, for the txindex scenario the leveldb cache make
24// a meaningful difference: https://github.com/bitcoin/bitcoin/pull/8273#issuecomment-229601991
25//! Max memory allocated to tx index DB specific cache in bytes.
26static constexpr uint64_t MAX_TX_INDEX_CACHE{1_GiB};
27//! Max memory allocated to all block filter index caches combined in bytes.
28static constexpr uint64_t MAX_FILTER_INDEX_CACHE{1_GiB};
29//! Max memory allocated to tx spenderindex DB specific cache in bytes.
30static constexpr uint64_t MAX_TXOSPENDER_INDEX_CACHE{1_GiB};
31//! Larger default dbcache on 64-bit systems with enough RAM.
32static constexpr uint64_t HIGH_DEFAULT_DBCACHE{1_GiB};
33//! Minimum detected RAM required for HIGH_DEFAULT_DBCACHE.
34static constexpr uint64_t HIGH_DEFAULT_DBCACHE_MIN_TOTAL_RAM{4_GiB};
35
36namespace node {
37uint64_t GetDefaultDBCache()
38{
39    if constexpr (sizeof(void*) >= 8) {
40        if (TryGetTotalRam().value_or(0) >= HIGH_DEFAULT_DBCACHE_MIN_TOTAL_RAM) {
41            return HIGH_DEFAULT_DBCACHE;
42        }
43    }
44    return DEFAULT_KERNEL_CACHE;
45}
46
47uint64_t CalculateDbCacheBytes(const ArgsManager& args)
48{
49    if (auto db_cache{args.GetIntArg("-dbcache")}) {
50        if (*db_cache < 0) db_cache = 0;
51        const uint64_t db_cache_bytes{SaturatingLeftShift<uint64_t>(*db_cache, 20)};
52        return std::max(MIN_DBCACHE_BYTES, std::min(db_cache_bytes, MAX_DBCACHE_BYTES));
53    }
54    return GetDefaultDBCache();
55}
56
57CacheSizes CalculateCacheSizes(const ArgsManager& args, size_t n_indexes)
58{
59    uint64_t total_cache{CalculateDbCacheBytes(args)};
60
61    // Allocate proportional to usage pattern benefit:
62    // - txindex (10%): serves getrawtransaction RPCs with mostly unique,
63    //   non-repetitive lookups across the entire blockchain.
64    // - blockfilterindex (5%): serves BIP 157 light clients that repeatedly
65    //   query recent blocks, benefiting from LevelDB cache, but the
66    //   working set for a typical 2-week offline gap is ~200kiB, well within 5%
67    //   of the total cache.
68    // - txospenderindex (5%): serves gettxspendingprevout RPCs with very
69    //   specific, rarely repeated outpoint queries.
70    // - coinstatsindex: intentionally not included here, since usage pattern
71    //   does not seem to suggest it would be necessary to cache.
72    IndexCacheSizes index_sizes;
73    index_sizes.tx_index = std::min(total_cache * 10 / 100, args.GetBoolArg("-txindex", DEFAULT_TXINDEX) ? MAX_TX_INDEX_CACHE : 0);
74    index_sizes.txospender_index = std::min(total_cache * 5 / 100, args.GetBoolArg("-txospenderindex", DEFAULT_TXOSPENDERINDEX) ? MAX_TXOSPENDER_INDEX_CACHE : 0);
75    if (n_indexes > 0) {
76        uint64_t max_cache = std::min(total_cache * 5 / 100, MAX_FILTER_INDEX_CACHE);
77        index_sizes.filter_index = max_cache / n_indexes;
78        total_cache -= index_sizes.filter_index * n_indexes;
79    }
80    total_cache -= index_sizes.tx_index;
81    total_cache -= index_sizes.txospender_index;
82    return {index_sizes, kernel::CacheSizes{total_cache}};
83}
84
85void LogOversizedDbCache(const ArgsManager& args) noexcept
86{
87    if (const auto total_ram{TryGetTotalRam()}) {
88        const uint64_t db_cache{CalculateDbCacheBytes(args)};
89        if (ShouldWarnOversizedDbCache(db_cache, *total_ram)) {
90            InitWarning(bilingual_str{tfm::format(_("A %zu MiB dbcache may be too large for a system memory of only %zu MiB."),
91                        db_cache / 1_MiB, *total_ram / 1_MiB)});
92        }
93    }
94}
95} // namespace node
96