[Tarantool-patches] [PATCH v6 0/5] Initial datetime implementation
Timur Safin
tsafin at tarantool.org
Thu Aug 19 05:56:28 MSK 2021
* Version #6 changes:
Massive changes and reshuffles to the patches in patchset, now we
consolidated them to 3 major parts:
- creation of a Lua module;
- serialization to MessagePack and other formats;
- Box storage support;
As a result of yesterday discussion we significantly simplified
datetime.lua API. We have dropped interval support, and made
implementation as immutable, as possible. Now object have these
major methods:
- add{}
- sub{}
- totable()
- set{}
Interface for constructors kept the same, but performance improved
due to removed loops over keys in hash.
We got rid of ctime()/asctime() methods, as they are useless. strftime()
is good enough for majority of similar cases.
In addition to these massive datetime.lua changes we have reshuffled code
for indices support - we have moved part introducing new field type from
serialization patch, to the more appropriate box indices patch.
datetime_to_string() has been reimplemented using SNPRINT facilities.
As a bonus part - mp_utils.h has been introduced to simiplify work with
integer values when they need to be encoded/decoded to/from MesagePack.
This API works regardless of a values signedness.
| I'm planning to resend updated datetime.lua patch as it's not yet
| feature-complete - there is no working set{} method
|
| Also we need to extend tests with a new API methods usage. Stay tuned!
* Version #5 changes:
- After performance evaluations it was decided to switch data type used
by `datetime.secs` from `int64_t` (which is boxed in LuaJIT) to
`double` (which is unboxed number).
- please see perf/datetime*.cc perf test as a benchmark we used for
comparison of 2 veriants of C implementation. Results are here -
https://gist.github.com/tsafin/618fbf847d258f6e7f5a75fdf9ea945b
* Version #4 changes:
A lot.
- Got rid of closures usage here and there. Benchmarks revealed there is
20x speed difference of hash with closure handlers to the case when we
check keys using sequence of simple ifs.
And despite the fact that it looks ugler, we have updated all places which
used to use closures - so much performance impact does not worth it;
- c-dt library now is accompanied with corresponding unit-tests;
- due to a new (old) way of exporting public symbols, which is now used by
Tarantool build, we have modified c-dt sources to use approach similar
to that used by xxhash (or ICU) - "namespaces" for public symbols.
If there is DT_NAMESPACE macro (e.g. DT_NAMESPACE=tnt_) defined at the
moment of compilation we rename all relevant public symbols to
use that "namespace" as prefix
#define dt_from_rdn DT_NAME(DT_NAMESPACE, dt_from_rdn)
C sources continue to use original name (now as a macro), but in Lua ffi
we have to use renamed symbol - `tnt_dt_from_rdn`.
- We have separated code which implement MessagePack related funcionality
from generic (i.e. stringization) support for datetime types.
Stringization is in `src/core/datetime.c`, but MessagePack support is in
`src/core/mp_datetime.c`.
- `ctime` and `asctime` now use reentrant versions (i.e. `ctime_r` instead of
`ctime`, and `asctime_r` instead of `asctime`). This allows us to avoid
nasty problem with GC where it was possible to corrupt returned
static buffer regardless the fact that it was immediately passed
to `ffi.string`.
`test/app-tap/gh-5632-6050-6259-gc-buf-reuse.test.lua` updated to check our
new api `datetime.ctime`, and `datetime.asctime`.
- Introduced MessagePack unit-test which check C implementation (mp
encode/decode, mp_snprint, mp_fprint)
- Some special efforts have been taken to make sure we deal correctly
with datetime stamps which were before Unix Epoch (1970-01-01), i.e.
for negative stamps or timezones against epoch.
- And last, but not the least: in addition to usual getters like
`timestamp`, `nanoseconds`, `epoch`, we have introduced function
modifiers `to_utc()` or `to_tz(offset)` which allow to manipulate with
datetime timezone `.offset` field. Actually it does not do much now
(only reattributing object with different offset, but not changed
actual timestamp, which is UTC normalized). But different timestamp
modifies textual representation, which simplify debugging.
* Version #3 changes:
- renamed `struct datetime_t` to `struct datetime`, and `struct
datetime_interval_t` to `struct datetime_interval`;
- significantly reworked arguments checks in module api entries;
- fixed datetime comparisons;
- changed hints calculation to take into account fractional part;
- provided more comments here and there;
NB! There are MacOSX problems due to GLIBC specific code used (as Vlad
has already pointed out) - so additional patch, making it more
cross-compatible coming here soon...
* Version #2 changes:
- fixed problem with overloaded '-' and '+' operations for datetime
arguments;
- fixed messagepack serialization problems;
- heavily documented MessagePack serialization schema in the code;
- introduced working implementation of datetime hints for storage engines;
- made interval related names be more consistent, renamed durations and period
to intervals, i.e. t_datetime_duration to datetime_interval_t,
duration_* to interval_*, period to interval;
- properly implemented all reasonable cases of datetime+interval
arithmetic;
- moved all initialization code to utils.c;
- renamed core/mp_datetime.c to core/datetime.c because it makes more
sense now;
* Version #1 - initial RFC
In brief
--------
This patchset implements datetime lua support in box, with serialization
to messagepack, yaml, json and lua mode. Also it contains storage
engines' indices implementation for datetime type introduced.
* Current implementation is heavily influenced by Sci-Lua lua-time module
https://github.com/stepelu/lua-time
e.g. you could find very similar approach for handling of operations
with year or month long intervals (which should be handled differently than
usual intervals of seconds, or days).
* But internally we actually use Christian Hanson' c-dt module
https://github.com/chansen/c-dt
(though it has been modified slightly for cleaner integration
into our cmake-based build process).
Datetime Module API
-------------------
Small draft of documentation for our `datetime` module API has been
extracted to the discussion topic there -
https://github.com/tarantool/tarantool/discussions/6244#discussioncomment-1043988
We try to update documentation there once any relevant change introdcued
to the implementaton.
Messagepack serialization schema
--------------------------------
In short it looks like:
- now we introduce new MP_EXT extension type #4;
- we may save 1 required and 2 optional fields for datetime field;
In all gory details it's explained in MessagePack serialization schema depicted here:
https://github.com/tarantool/tarantool/discussions/6244#discussioncomment-1043990
https://github.com/tarantool/tarantool/issues/5941
https://github.com/tarantool/tarantool/issues/5946
https://github.com/tarantool/tarantool/tree/tsafin/gh-5941-datetime-v5
Timur Safin (5):
build, lua: built-in module datetime
box, datetime: messagepack support for datetime
box, datetime: datetime comparison for indices
datetime: perf test for datetime parser
datetime: changelog for datetime module
.gitmodules | 3 +
CMakeLists.txt | 8 +
.../gh-5941-datetime-type-support.md | 6 +
cmake/BuildCDT.cmake | 10 +
extra/exports | 35 ++
perf/CMakeLists.txt | 3 +
perf/datetime-common.h | 105 ++++
perf/datetime-compare.cc | 213 +++++++
perf/datetime-parser.cc | 105 ++++
src/CMakeLists.txt | 5 +-
src/box/field_def.c | 35 +-
src/box/field_def.h | 1 +
src/box/lua/serialize_lua.c | 8 +-
src/box/msgpack.c | 7 +-
src/box/tuple_compare.cc | 77 +++
src/lib/core/CMakeLists.txt | 5 +-
src/lib/core/datetime.c | 134 +++++
src/lib/core/datetime.h | 121 ++++
src/lib/core/mp_datetime.c | 171 ++++++
src/lib/core/mp_datetime.h | 64 ++
src/lib/core/mp_extension_types.h | 1 +
src/lib/core/mp_utils.h | 64 ++
src/lib/mpstream/mpstream.c | 11 +
src/lib/mpstream/mpstream.h | 4 +
src/lua/datetime.lua | 567 ++++++++++++++++++
src/lua/init.c | 4 +-
src/lua/msgpack.c | 12 +
src/lua/msgpackffi.lua | 18 +
src/lua/serializer.c | 4 +
src/lua/serializer.h | 2 +
src/lua/utils.c | 27 +
src/lua/utils.h | 12 +
test/app-tap/datetime.test.lua | 213 +++++++
test/engine/datetime.result | 77 +++
test/engine/datetime.test.lua | 35 ++
test/unit/CMakeLists.txt | 3 +-
test/unit/datetime.c | 383 ++++++++++++
test/unit/datetime.result | 471 +++++++++++++++
third_party/c-dt | 1 +
third_party/lua-cjson/lua_cjson.c | 8 +
third_party/lua-yaml/lyaml.cc | 6 +-
41 files changed, 3017 insertions(+), 22 deletions(-)
create mode 100644 changelogs/unreleased/gh-5941-datetime-type-support.md
create mode 100644 cmake/BuildCDT.cmake
create mode 100644 perf/datetime-common.h
create mode 100644 perf/datetime-compare.cc
create mode 100644 perf/datetime-parser.cc
create mode 100644 src/lib/core/datetime.c
create mode 100644 src/lib/core/datetime.h
create mode 100644 src/lib/core/mp_datetime.c
create mode 100644 src/lib/core/mp_datetime.h
create mode 100644 src/lib/core/mp_utils.h
create mode 100644 src/lua/datetime.lua
create mode 100755 test/app-tap/datetime.test.lua
create mode 100644 test/engine/datetime.result
create mode 100644 test/engine/datetime.test.lua
create mode 100644 test/unit/datetime.c
create mode 100644 test/unit/datetime.result
create mode 160000 third_party/c-dt
--
2.29.2
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