before this change, we use `update_item_suffix` as a format string
fed to `format(...)`, which is resolved to `seastar::format()`.
but with a patch which migrates the `seastar::format()` to the backend
with compile-time format check, the caller sites using `format()` would
fail to build, because `update_item_suffix` is not a `constexpr`:
```
/home/kefu/.local/bin/clang++ -DFMT_SHARED -DSCYLLA_BUILD_MODE=release -DSEASTAR_API_LEVEL=7 -DSEASTAR_LOGGER_COMPILE_TIME_FMT -DSEASTAR_LOGGER_TYPE_STDOUT -DSEASTAR_SCHEDULING_GROUPS_COUNT=16 -DSEASTAR_SSTRING -DXXH_PRIVATE_API -DCMAKE_INTDIR=\"RelWithDebInfo\" -I/home/kefu/dev/scylladb -I/home/kefu/dev/scylladb/build/gen -I/home/kefu/dev/scylladb/seastar/include -I/home/kefu/dev/scylladb/build/seastar/gen/include -I/home/kefu/dev/scylladb/build/seastar/gen/src -isystem /home/kefu/dev/scylladb/abseil -isystem /home/kefu/dev/scylladb/build/rust -ffunction-sections -fdata-sections -O3 -g -gz -std=gnu++20 -fvisibility=hidden -Wall -Werror -Wextra -Wno-error=deprecated-declarations -Wimplicit-fallthrough -Wno-c++11-narrowing -Wno-deprecated-copy -Wno-mismatched-tags -Wno-missing-field-initializers -Wno-overloaded-virtual -Wno-unsupported-friend -Wno-enum-constexpr-conversion -Wno-unused-parameter -ffile-prefix-map=/home/kefu/dev/scylladb=. -march=westmere -mllvm -inline-threshold=2500 -fno-slp-vectorize -U_FORTIFY_SOURCE -Werror=unused-result -MD -MT test/perf/CMakeFiles/test-perf.dir/RelWithDebInfo/perf_alternator.cc.o -MF test/perf/CMakeFiles/test-perf.dir/RelWithDebInfo/perf_alternator.cc.o.d -o test/perf/CMakeFiles/test-perf.dir/RelWithDebInfo/perf_alternator.cc.o -c /home/kefu/dev/scylladb/test/perf/perf_alternator.cc
/home/kefu/dev/scylladb/test/perf/perf_alternator.cc:249:69: error: call to consteval function 'fmt::basic_format_string<char, const char (&)[1]>::basic_format_string<const char *, 0>' is not a constant expression
249 | return make_request(cli, "UpdateItem", prefix + seastar::format(update_item_suffix, ""));
| ^
/usr/include/fmt/core.h:2776:67: note: read of non-constexpr variable 'update_item_suffix' is not allowed in a constant expression
2776 | FMT_CONSTEVAL FMT_INLINE basic_format_string(const S& s) : str_(s) {
| ^
/home/kefu/dev/scylladb/test/perf/perf_alternator.cc:249:69: note: in call to 'basic_format_string<const char *, 0>(update_item_suffix)'
249 | return make_request(cli, "UpdateItem", prefix + seastar::format(update_item_suffix, ""));
| ^~~~~~~~~~~~~~~~~~
/home/kefu/dev/scylladb/test/perf/perf_alternator.cc:198:6: note: declared here
198 | auto update_item_suffix = R"(
| ^
```
so, to prepare the change switching to compile-time format checking,
let's mark this variable `static constexpr`. this is also more correct,
as this variable is
* a compile time constant, and
* is not shared across different compilation units.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#18685
The code is based on similar idea as perf_simple_query. The main differences are:
- it starts full scylla process
- communicates with alternator via http (localhost)
- uses richer table schema with all dynamoDB types instead of only strings
Testing code runs in the same process as scylla so we can easily get various perf counters (tps, instr, allocation, etc).
Results on my machine (with 1 vCPU):
> ./build/release/scylla perf-alternator-workloads --workdir ~/tmp --smp 1 --developer-mode 1 --alternator-port 8000 --alternator-write-isolation forbid --workload read --duration 10 2> /dev/null
...
median 23402.59616090321
median absolute deviation: 598.77
maximum: 24014.41
minimum: 19990.34
> ./build/release/scylla perf-alternator-workloads --workdir ~/tmp --smp 1 --developer-mode 1 --alternator-port 8000 --alternator-write-isolation forbid --workload write --duration 10 2> /dev/null
...
median 16089.34211320635
median absolute deviation: 552.65
maximum: 16915.95
minimum: 14781.97
The above seem more realistic than results from perf_simple_query which are 96k and 49k tps (per core).
