This change takes the observation that previous dbm.IsKeyInDomain which searches for [start, end) was performing too many byteslice comparisons. Instead we start off by sorting all the values in the store.unsortedCache, and then apply a modified binary search to look for values that fall within the domain [start, end) The procedure involves: * iterating over all items to build a list of all keys -- O(n) * invoking sort.Strings immediately, of which we anyways eventually invoke sort.Slice(unsorted, ...) which uses Quicksort -- O(nlog(n)) or O(n^2) worst case * invoking modified binary search which is O(log(n)) * 2 ~ O(log(n)) to search for the [start, end) range indices for a total approximate complexity of: Best case: O(n) + O(n(log(n))) + O(log(n)) ~= O(nlog(n)) Worst case: O(n) + O(n^2) + O(log(n)) ~= O(n^2) instead of previously: * iterating over all the unsorted items and invoking dbm.IsKeyInDomain: bytes.Compare ~ O(n) + O(n*s*e) where s -- len(start), e -- len(end) for overall complexity of O(n*s*e) * invoking sort.Slice(unsorted, ...) which uses Quicksort -- O(nlog(n)) or O(n^2) worst case for a total approximate complexity of: Best case: O(n) + O(n*s*e) + O(nlog(n)) ~= O(n*s*e) ~ O(n^2) Worst case: O(n) + O(n*s*e) + O(n^2) ~= O(n*s*e) ~ O(n^2) Ordinarily we'd combine the n*s*e to be n*m, but really the comparisons between (start & key, end & key) are profound that it makes sense to keep them as factors. The overall benchmark results vindicate our choice of isolating the factors (n*s*e) The benchmarks show that as the number of keys to iterate grows, the new code grows gracefully in a somewhat linear growth, notice for CAcheKVStoreIterator*, when we go from: * 1,000 to 10,000 keys: 120us->1,600us (13X) old vs 95us->900us (9.47X) new * 50,000 to 100,000 keys: 19ms->100ms (5.3X) old vs 5.5ms->17ms (3X) new ```shell time/op GetValidator-8 5.8ms ± 2% 4.7ms ± 1% -17.69% (p=0.000 n=10+10) OneBankSendTxPerBlock-8 3.2ms ± 2% 2.8ms ± 1% -10.80% (p=0.000 n=7+10) OneBankMultiSendTxPerBlock-8 3.1ms ± 3% 2.9ms ± 2% -8.36% (p=0.000 n=10+10) AccountMapperSetAccount-8 8.6µs ± 1% 7.8µs ± 1% -9.74% (p=0.000 n=10+10) CacheKVStoreIterator500-8 64µs ± 6% 51µs ± 6% -19.22% (p=0.000 n=10+9) CacheKVStoreIterator1000-8 0.12ms ± 4% 95µs ± 4% -19.55% (p=0.000 n=10+10) CacheKVStoreIterator10000-8 1.6ms ± 4% 0.90ms ± 1% -42.11% (p=0.000 n=10+10) CacheKVStoreIterator50000-8 19ms ± 5% 5.5ms ± 1% -71.35% (p=0.000 n=10+10) CacheKVStoreIterator100000-8 0.10s ± 23% 17ms ± 7% -83.44% (p=0.000 n=10+10) CacheKVStoreGetNoKeyFound-8 1.3µs ± 6% 0.90µs ± 3% -31.19% (p=0.000 n=9+9) CacheKVStoreGetKeyFound-8 0.66µs ± 6% 0.56µs ± 2% -14.81% (p=0.000 n=10+9) alloc/op B/op BlockProvision-8 0.11kB ± 0% 0.10kB ± 0% -7.14% (p=0.000 n=10+10) CacheKVStoreIterator50000-8 0.89MB ± 6% 0.53MB ± 1% -40.85% (p=0.000 n=10+10) CacheKVStoreIterator100000-8 6.3MB ± 23% 1.6MB ± 6% -74.17% (p=0.000 n=10+10) CacheKVStoreGetNoKeyFound-8 0.26kB ± 0% 0.23kB ± 1% -11.53% (p=0.000 n=10+8) allocs/op (count) AccountMapperSetAccount-8 42 ± 0% 38 ± 0% -9.52% (p=0.000 n=10+10) BlockProvision-8 6.0 ± 0% 5.0 ± 0% -16.67% (p=0.000 n=10+10) CacheKVStoreIterator1000-8 14 ± 0% 13 ± 0% -7.14% (p=0.002 n=8+10) CacheKVStoreIterator10000-8 0.15k ± 2% 76 ± 1% -49.00% (p=0.000 n=7+10) CacheKVStoreIterator50000-8 8.9k ± 11% 2.0k ± 2% -77.60% (p=0.000 n=10+10) CacheKVStoreIterator100000-8 0.10M ± 26% 13k ± 12% -86.89% (p=0.000 n=10+10) CacheKVStoreGetNoKeyFound-8 5.0 ± 0% 4.0 ± 0% -20.00% (p=0.000 n=10+10) ``` Note: Purposefully using a commit off master that doesn't include the buggy code that caused x/bank.BenchmarkOneBank* to fail per issue https://github.com/cosmos/cosmos-sdk/issues/10023 Updates #9876 /cc @cuonglm @kirbyquerby <!-- The default pull request template is for types feat, fix, or refactor. For other templates, add one of the following parameters to the url: - template=docs.md - template=other.md --> ## Description Closes: #XXXX <!-- Add a description of the changes that this PR introduces and the files that are the most critical to review. --> --- ### Author Checklist *All items are required. Please add a note to the item if the item is not applicable and please add links to any relevant follow up issues.* I have... - [x] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title - [x] added `!` to the type prefix if API or client breaking change - [x] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting)) - [x] provided a link to the relevant issue or specification - [x] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules) - [x] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#testing) - [ ] added a changelog entry to `CHANGELOG.md` - [x] included comments for [documenting Go code](https://blog.golang.org/godoc) - [ ] updated the relevant documentation or specification - [ ] reviewed "Files changed" and left comments if necessary - [ ] confirmed all CI checks have passed ### Reviewers Checklist *All items are required. Please add a note if the item is not applicable and please add your handle next to the items reviewed if you only reviewed selected items.* I have... - [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title - [ ] confirmed `!` in the type prefix if API or client breaking change - [ ] confirmed all author checklist items have been addressed - [ ] reviewed state machine logic - [ ] reviewed API design and naming - [ ] reviewed documentation is accurate - [ ] reviewed tests and test coverage - [ ] manually tested (if applicable) |
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.. | ||
cache | ||
cachekv | ||
cachemulti | ||
dbadapter | ||
gaskv | ||
iavl | ||
internal | ||
listenkv | ||
mem | ||
prefix | ||
rootmulti | ||
tracekv | ||
transient | ||
types | ||
README.md | ||
firstlast.go | ||
reexport.go | ||
store.go |
README.md
Store
CacheKV
cachekv.Store
is a wrapper KVStore
which provides buffered writing / cached reading functionalities over the underlying KVStore
.
type Store struct {
cache map[string]cValue
parent types.KVStore
}
Get
Store.Get()
checks Store.cache
first in order to find if there is any cached value associated with the key. If the value exists, the function returns it. If not, the function calls Store.parent.Get()
, sets the key-value pair to the Store.cache
, and returns it.
Set
Store.Set()
sets the key-value pair to the Store.cache
. cValue
has the field dirty bool
which indicates whether the cached value is different from the underlying value. When Store.Set()
cache new pair, the cValue.dirty
is set true so when Store.Write()
is called it can be written to the underlying store.
Iterator
Store.Iterator()
have to traverse on both caches items and the original items. In Store.iterator()
, two iterators are generated for each of them, and merged. memIterator
is essentially a slice of the KVPair
s, used for cached items. mergeIterator
is a combination of two iterators, where traverse happens ordered on both iterators.
CacheMulti
cachemulti.Store
is a wrapper MultiStore
which provides buffered writing / cached reading functionalities over the underlying MutliStore
type Store struct {
db types.CacheKVStore
stores map[types.StoreKey] types.CacheWrap
}
cachemulti.Store
branches all substores in its constructor and hold them in Store.stores
. Store.GetKVStore()
returns the store from Store.stores
, and Store.Write()
recursively calls CacheWrap.Write()
on the substores.
DBAdapter
dbadapter.Store
is a adapter for dbm.DB
making it fulfilling the KVStore
interface.
type Store struct {
dbm.DB
}
dbadapter.Store
embeds dbm.DB
, so most of the KVStore
interface functions are implemented. The other functions(mostly miscellaneous) are manually implemented.
IAVL
iavl.Store
is a base-layer self-balancing merkle tree. It is guaranteed that
- Get & set operations are
O(log n)
, wheren
is the number of elements in the tree - Iteration efficiently returns the sorted elements within the range
- Each tree version is immutable and can be retrieved even after a commit(depending on the pruning settings)
Specification and implementation of IAVL tree can be found in [https://github.com/tendermint/iavl].
GasKV
gaskv.Store
is a wrapper KVStore
which provides gas consuming functionalities over the underlying KVStore
.
type Store struct {
gasMeter types.GasMeter
gasConfig types.GasConfig
parent types.KVStore
}
When each KVStore
methods are called, gaskv.Store
automatically consumes appropriate amount of gas depending on the Store.gasConfig
.
Prefix
prefix.Store
is a wrapper KVStore
which provides automatic key-prefixing functionalities over the underlying KVStore
.
type Store struct {
parent types.KVStore
prefix []byte
}
When Store.{Get, Set}()
is called, the store forwards the call to its parent, with the key prefixed with the Store.prefix
.
When Store.Iterator()
is called, it does not simply prefix the Store.prefix
, since it does not work as intended. In that case, some of the elements are traversed even they are not starting with the prefix.
RootMulti
rootmulti.Store
is a base-layer MultiStore
where multiple KVStore
can be mounted on it and retrieved via object-capability keys. The keys are memory addresses, so it is impossible to forge the key unless an object is a valid owner(or a receiver) of the key, according to the object capability principles.
TraceKV
tracekv.Store
is a wrapper KVStore
which provides operation tracing functionalities over the underlying KVStore
.
type Store struct {
parent types.KVStore
writer io.Writer
context types.TraceContext
}
When each KVStore
methods are called, tracekv.Store
automatically logs traceOperation
to the Store.writer
.
type traceOperation struct {
Operation operation
Key string
Value string
Metadata map[string]interface{}
}
traceOperation.Metadata
is filled with Store.context
when it is not nil. TraceContext
is a map[string]interface{}
.
Transient
transient.Store
is a base-layer KVStore
which is automatically discarded at the end of the block.
type Store struct {
dbadapter.Store
}
Store.Store
is a dbadapter.Store
with a dbm.NewMemDB()
. All KVStore
methods are reused. When Store.Commit()
is called, new dbadapter.Store
is assigned, discarding previous reference and making it garbage collected.