Snippet to demonstrate why we should be encouraging customers to send batch update_ddl instead of one by one

RESULTS.md

Unbatched

$ time python3 foo.py 
real	10m6.379s
user	0m0.612s
sys	0m0.174s

Batched

$ time BATCHED=true python3 foo.py 
real	0m27.215s
user	0m0.487s
sys	0m0.131s

Comparison result

95.5% reduction in time if all those CREATE TABLE statements are sent in bulk.

update_ddl_comparisons.py

from google.cloud import spanner_v1 as spanner

def main():
    client = spanner.Client()
    ins = client.instance('django-tests')
    if not ins.exists():
        ins.configuration_name = 'projects/appdev-soda-spanner-staging/instanceConfigs/regional-us-west2'
        _ = ins.create()

    db = ins.database('dbx')
    if not db.exists():
        db.create()

    stmts = [
        "CREATE TABLE django_content_type (id INT64 NOT NULL, app_label STRING(100) NOT NULL, model STRING(100) NOT NULL) PRIMARY KEY(id)",
        "CREATE TABLE auth_permission (id INT64 NOT NULL, name STRING(255) NOT NULL, content_type_id INT64 NOT NULL, codename STRING(100) NOT NULL) PRIMARY KEY(id)",
        "CREATE TABLE auth_group (id INT64 NOT NULL, name STRING(150) NOT NULL) PRIMARY KEY(id)",
        "CREATE TABLE auth_group_permissions (id INT64 NOT NULL, group_id INT64 NOT NULL, permission_id INT64 NOT NULL) PRIMARY KEY(id)",
        "CREATE TABLE auth_user (id INT64 NOT NULL, password STRING(128) NOT NULL, last_login TIMESTAMP, is_superuser BOOL NOT NULL, username STRING(150) NOT NULL, first_name STRING(30) NOT NULL, last_name STRING(150) NOT NULL, email STRING(254) NOT NULL, is_staff BOOL NOT NULL, is_active BOOL NOT NULL, date_joined TIMESTAMP NOT NULL) PRIMARY KEY(id)",
        "CREATE TABLE auth_user_groups (id INT64 NOT NULL, user_id INT64 NOT NULL, group_id INT64 NOT NULL) PRIMARY KEY(id)",
        "CREATE TABLE auth_user_user_permissions (id INT64 NOT NULL, user_id INT64 NOT NULL, permission_id INT64 NOT NULL) PRIMARY KEY(id)",
        "CREATE TABLE django_session (session_key STRING(40) NOT NULL, session_data STRING(MAX) NOT NULL, expire_date TIMESTAMP NOT NULL) PRIMARY KEY(session_key)",
        "CREATE TABLE basic_article (id INT64 NOT NULL, headline STRING(100) NOT NULL, pub_date TIMESTAMP NOT NULL) PRIMARY KEY(id)",
        "CREATE TABLE basic_featuredarticle (id INT64 NOT NULL, article_id INT64 NOT NULL) PRIMARY KEY(id)",
        "CREATE TABLE basic_selfref (id INT64 NOT NULL, selfref_id INT64, article_id INT64) PRIMARY KEY(id)",
        "CREATE UNIQUE INDEX django_content_type_app_label_model_76bd3d3b_uniq ON django_content_type (app_label, model)",
        "CREATE UNIQUE INDEX auth_permission_content_type_id_codename_01ab375a_uniq ON auth_permission (content_type_id, codename)",
        "CREATE INDEX auth_permission_content_type_id_2f476e4b ON auth_permission (content_type_id)",
        "CREATE UNIQUE INDEX auth_group_permissions_group_id_permission_id_0cd325b0_uniq ON auth_group_permissions (group_id, permission_id)",
        "CREATE INDEX auth_group_permissions_group_id_b120cbf9 ON auth_group_permissions (group_id)",
        "CREATE INDEX auth_group_permissions_permission_id_84c5c92e ON auth_group_permissions (permission_id)",
        "CREATE UNIQUE INDEX auth_user_groups_user_id_group_id_94350c0c_uniq ON auth_user_groups (user_id, group_id)",
        "CREATE INDEX auth_user_groups_user_id_6a12ed8b ON auth_user_groups (user_id)",
        "CREATE INDEX auth_user_groups_group_id_97559544 ON auth_user_groups (group_id)",
        "CREATE UNIQUE INDEX auth_user_user_permissions_user_id_permission_id_14a6b632_uniq ON auth_user_user_permissions (user_id, permission_id)",
        "CREATE INDEX auth_user_user_permissions_user_id_a95ead1b ON auth_user_user_permissions (user_id)",
        "CREATE INDEX auth_user_user_permissions_permission_id_1fbb5f2c ON auth_user_user_permissions (permission_id)",
        "CREATE INDEX django_session_expire_date_a5c62663 ON django_session (expire_date)",
        "CREATE INDEX basic_selfref_selfref_id_fa437744 ON basic_selfref (selfref_id)",
        "CREATE INDEX basic_selfref_article_id_b9f2fc8c ON basic_selfref (article_id)",
    ]

    if os.environ.get('BATCHED'):
        lro = db.update_ddl(stmts)
        print(lro.result())
    else: # Unbatched
        for stmt in stmts:
            lro = db.update_ddl([stmt])
            print(lro.result())

    db.drop()

if __name__ == '__main__':
    main()