Linking user compiled SQLite from Python to reproduce "too many variables" error in Optuna.

Dockerfile

FROM optuna/optuna:py3.7-dev

RUN apt-get update

# Compile sqlite with a low SQLITE_MAX_VARIABLE_NUMBER.
RUN mkdir sqlite3_tmp
WORKDIR sqlite3_tmp
RUN wget https://www.sqlite.org/src/tarball/sqlite.tar.gz
RUN tar zxf sqlite.tar.gz
ENV CFLAGS -DSQLITE_ENABLE_FTS3 \
  -DSQLITE_MAX_VARIABLE_NUMBER=10 \
  -DSQLITE_ENABLE_FTS3_PARENTHESIS \
  -DSQLITE_ENABLE_FTS4 \
  -DSQLITE_ENABLE_FTS5 \
  -DSQLITE_ENABLE_JSON1 \
  -DSQLITE_ENABLE_LOAD_EXTENSION \
  -DSQLITE_ENABLE_RTREE \
  -DSQLITE_ENABLE_STAT4 \
  -DSQLITE_ENABLE_UPDATE_DELETE_LIMIT \
  -DSQLITE_SOUNDEX \
  -DSQLITE_TEMP_STORE=3 \
  -DSQLITE_USE_URI \
  -O2 \
  -fPIC
ENV PREFIX /usr/local
WORKDIR sqlite
RUN LIBS="-lm" ./configure --disable-tcl --enable-shared --enable-tempstore=always --prefix="${PREFIX}"
RUN make
RUN make install
# Overwrite existing sqlite shared libraries (that Python will look for), for testing purpose.
RUN mv ${PREFIX}/lib/libsqlite3* /usr/lib/x86_64-linux-gnu/

WORKDIR /workspaces

COPY sqlite3_too_many_variables.py .

sqlite3_too_many_variables.py

import optuna

def objective(trial):
    return trial.suggest_float("x", 0, 3) * 2

study = optuna.create_study(study_name="1457", storage="sqlite:///1457.db")
study.optimize(objective, n_trials=20)

print(len(study.trials))