perf(ingest/bigquery): Improve bigquery usage disk usage and speed (#7825)

metadata-ingestion/setup.cfg

@@ -80,11 +80,9 @@ markers =
     integration: marks tests to only run in integration (deselect with '-m "not integration"')
     integration_batch_1: mark tests to only run in batch 1 of integration tests. This is done mainly for parallelisation (deselect with '-m not integration_batch_1')
     slow_integration: marks tests that are too slow to even run in integration (deselect with '-m "not slow_integration"')
-    performance: marks tests that are sparingly run to measure performance (deselect with '-m "not performance"')
 testpaths =
     tests/unit
     tests/integration
-    tests/performance
 
 [coverage:run]
 # Because of some quirks in the way setup.cfg, coverage.py, pytest-cov,

metadata-ingestion/setup.py

@@ -408,6 +408,7 @@ base_dev_requirements = {
     # We should make an effort to keep it up to date.
     "black==22.12.0",
     "coverage>=5.1",
+    "faker>=18.4.0",
     "flake8>=3.8.3",  # DEPRECATION: Once we drop Python 3.7, we can pin to 6.x.
     "flake8-tidy-imports>=4.3.0",
     "flake8-bugbear==23.3.12",

metadata-ingestion/src/datahub/ingestion/source/bigquery_v2/bigquery.py

@@ -516,7 +516,7 @@ class BigqueryV2Source(StatefulIngestionSourceBase, TestableSource):
                 self.report.report_dropped(project_id.id)
                 continue
             logger.info(f"Processing project: {project_id.id}")
-            self.report.set_project_state(project_id.id, "Metadata Extraction")
+            self.report.set_ingestion_stage(project_id.id, "Metadata Extraction")
             yield from self._process_project(conn, project_id)
 
         if self._should_ingest_usage():
@@ -526,7 +526,7 @@ class BigqueryV2Source(StatefulIngestionSourceBase, TestableSource):
 
         if self._should_ingest_lineage():
             for project in projects:
-                self.report.set_project_state(project.id, "Lineage Extraction")
+                self.report.set_ingestion_stage(project.id, "Lineage Extraction")
                 yield from self.generate_lineage(project.id)
 
     def get_workunits(self) -> Iterable[MetadataWorkUnit]:
@@ -671,7 +671,7 @@ class BigqueryV2Source(StatefulIngestionSourceBase, TestableSource):
 
         if self.config.profiling.enabled:
             logger.info(f"Starting profiling project {project_id}")
-            self.report.set_project_state(project_id, "Profiling")
+            self.report.set_ingestion_stage(project_id, "Profiling")
             yield from self.profiler.get_workunits(
                 project_id=project_id,
                 tables=db_tables,

metadata-ingestion/src/datahub/ingestion/source/bigquery_v2/bigquery_config.py

@@ -193,7 +193,7 @@ class BigQueryV2Config(
 
     file_backed_cache_size: int = Field(
         hidden_from_docs=True,
-        default=200,
+        default=2000,
         description="Maximum number of entries for the in-memory caches of FileBacked data structures.",
     )
 

metadata-ingestion/src/datahub/ingestion/source/bigquery_v2/bigquery_report.py

@@ -2,7 +2,7 @@ import collections
 import dataclasses
 import logging
 from dataclasses import dataclass, field
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import Counter, Dict, List, Optional
 
 import pydantic
@@ -70,6 +70,7 @@ class BigQueryV2Report(ProfilingSqlReport):
     num_query_events: int = 0
     num_filtered_read_events: int = 0
     num_filtered_query_events: int = 0
+    num_usage_query_hash_collisions: int = 0
     num_operational_stats_workunits_emitted: int = 0
     read_reasons_stat: Counter[str] = dataclasses.field(
         default_factory=collections.Counter
@@ -77,20 +78,24 @@ class BigQueryV2Report(ProfilingSqlReport):
     operation_types_stat: Counter[str] = dataclasses.field(
         default_factory=collections.Counter
     )
-    current_project_status: Optional[str] = None
+    usage_state_size: Optional[str] = None
+    ingestion_stage: Optional[str] = None
+    ingestion_stage_durations: Dict[str, str] = field(default_factory=TopKDict)
 
-    timer: Optional[PerfTimer] = field(
+    _timer: Optional[PerfTimer] = field(
         default=None, init=False, repr=False, compare=False
     )
 
-    def set_project_state(self, project: str, stage: str) -> None:
+    def set_ingestion_stage(self, project: str, stage: str) -> None:
-        if self.timer:
+        if self._timer:
+            elapsed = f"{self._timer.elapsed_seconds():.2f}"
             logger.info(
-                f"Time spent in stage <{self.current_project_status}>: "
+                f"Time spent in stage <{self.ingestion_stage}>: {elapsed} seconds"
-                f"{self.timer.elapsed_seconds():.2f} seconds"
             )
+            if self.ingestion_stage:
+                self.ingestion_stage_durations[self.ingestion_stage] = elapsed
         else:
-            self.timer = PerfTimer()
+            self._timer = PerfTimer()
 
-        self.current_project_status = f"{project}: {stage} at {datetime.now()}"
+        self.ingestion_stage = f"{project}: {stage} at {datetime.now(timezone.utc)}"
-        self.timer.start()
+        self._timer.start()

metadata-ingestion/src/datahub/ingestion/source/bigquery_v2/usage.py

@@ -1,5 +1,7 @@
+import hashlib
 import json
 import logging
+import os
 import textwrap
 import time
 import uuid
@@ -18,6 +20,7 @@ from typing import (
     Union,
 )
 
+import humanfriendly
 from google.cloud.bigquery import Client as BigQueryClient
 from google.cloud.logging_v2.client import Client as GCPLoggingClient
 from ratelimiter import RateLimiter
@@ -44,7 +47,10 @@ from datahub.ingestion.source.bigquery_v2.common import (
     _make_gcp_logging_client,
     get_bigquery_client,
 )
-from datahub.ingestion.source.usage.usage_common import make_usage_workunit
+from datahub.ingestion.source.usage.usage_common import (
+    TOTAL_BUDGET_FOR_QUERY_LIST,
+    make_usage_workunit,
+)
 from datahub.metadata.schema_classes import OperationClass, OperationTypeClass
 from datahub.utilities.file_backed_collections import ConnectionWrapper, FileBackedDict
 from datahub.utilities.perf_timer import PerfTimer
@@ -79,6 +85,8 @@ OPERATION_STATEMENT_TYPES = {
 }
 
 READ_STATEMENT_TYPES: List[str] = ["SELECT"]
+STRING_ENCODING = "utf-8"
+MAX_QUERY_LENGTH = TOTAL_BUDGET_FOR_QUERY_LIST
 
 
 @dataclass(frozen=True, order=True)
@@ -157,6 +165,7 @@ class BigQueryUsageState(Closeable):
     read_events: FileBackedDict[ReadEvent]
     query_events: FileBackedDict[QueryEvent]
     column_accesses: FileBackedDict[Tuple[str, str]]
+    queries: FileBackedDict[str]
 
     def __init__(self, config: BigQueryV2Config):
         self.conn = ConnectionWrapper()
@@ -172,6 +181,10 @@ class BigQueryUsageState(Closeable):
                 "user": lambda e: e.actor_email,
             },
             cache_max_size=config.file_backed_cache_size,
+            # Evict entire cache to reduce db calls.
+            cache_eviction_batch_size=max(int(config.file_backed_cache_size * 0.9), 1),
+            delay_index_creation=True,
+            should_compress_value=True,
         )
         # Keyed by job_name
         self.query_events = FileBackedDict[QueryEvent](
@@ -182,6 +195,9 @@ class BigQueryUsageState(Closeable):
                 "is_read": lambda e: int(e.statementType in READ_STATEMENT_TYPES),
             },
             cache_max_size=config.file_backed_cache_size,
+            cache_eviction_batch_size=max(int(config.file_backed_cache_size * 0.9), 1),
+            delay_index_creation=True,
+            should_compress_value=True,
         )
         # Created just to store column accesses in sqlite for JOIN
         self.column_accesses = FileBackedDict[Tuple[str, str]](
@@ -189,7 +205,10 @@ class BigQueryUsageState(Closeable):
             tablename="column_accesses",
             extra_columns={"read_event": lambda p: p[0], "field": lambda p: p[1]},
             cache_max_size=config.file_backed_cache_size,
+            cache_eviction_batch_size=max(int(config.file_backed_cache_size * 0.9), 1),
+            delay_index_creation=True,
         )
+        self.queries = FileBackedDict[str](cache_max_size=config.file_backed_cache_size)
 
     def close(self) -> None:
         self.read_events.close()
@@ -197,12 +216,23 @@ class BigQueryUsageState(Closeable):
         self.column_accesses.close()
         self.conn.close()
 
+        self.queries.close()
+
+    def create_indexes(self) -> None:
+        self.read_events.create_indexes()
+        self.query_events.create_indexes()
+        self.column_accesses.create_indexes()
+
     def standalone_events(self) -> Iterable[AuditEvent]:
-        for read_event in self.read_events.values():
+        query = """
+        SELECT r.value, q.value
+        FROM read_events r
+        LEFT JOIN query_events q ON r.name = q.key
+        """
+        for read_value, query_value in self.read_events.sql_query_iterator(query):
+            read_event = self.read_events.deserializer(read_value)
             query_event = (
-                self.query_events.get(read_event.jobName)
+                self.query_events.deserializer(query_value) if query_value else None
-                if read_event.jobName
-                else None
             )
             yield AuditEvent(read_event=read_event, query_event=query_event)
         for _, query_event in self.query_events.items_snapshot("NOT is_read"):
@@ -293,6 +323,16 @@ class BigQueryUsageState(Closeable):
                 column_freq=json.loads(row["column_freq"] or "[]"),
             )
 
+    def report_disk_usage(self, report: BigQueryV2Report) -> None:
+        report.usage_state_size = str(
+            {
+                "main": humanfriendly.format_size(os.path.getsize(self.conn.filename)),
+                "queries": humanfriendly.format_size(
+                    os.path.getsize(self.queries._conn.filename)
+                ),
+            }
+        )
+
 
 class BigQueryUsageExtractor:
     """
@@ -308,6 +348,8 @@ class BigQueryUsageExtractor:
     def __init__(self, config: BigQueryV2Config, report: BigQueryV2Report):
         self.config: BigQueryV2Config = config
         self.report: BigQueryV2Report = report
+        # Replace hash of query with uuid if there are hash conflicts
+        self.uuid_to_query: Dict[str, str] = {}
 
     def _is_table_allowed(self, table_ref: Optional[BigQueryTableRef]) -> bool:
         return (
@@ -328,6 +370,8 @@ class BigQueryUsageExtractor:
         try:
             with BigQueryUsageState(self.config) as usage_state:
                 self._ingest_events(events, table_refs, usage_state)
+                usage_state.create_indexes()
+                usage_state.report_disk_usage(self.report)
 
                 if self.config.usage.include_operational_stats:
                     yield from self._generate_operational_workunits(
@@ -335,6 +379,7 @@ class BigQueryUsageExtractor:
                     )
 
                 yield from self._generate_usage_workunits(usage_state)
+                usage_state.report_disk_usage(self.report)
         except Exception as e:
             logger.error("Error processing usage", exc_info=True)
             self.report.report_warning("usage-ingestion", str(e))
@@ -362,7 +407,7 @@ class BigQueryUsageExtractor:
     def _generate_operational_workunits(
         self, usage_state: BigQueryUsageState, table_refs: Collection[str]
     ) -> Iterable[MetadataWorkUnit]:
-        self.report.set_project_state("All", "Usage Extraction Operational Stats")
+        self.report.set_ingestion_stage("*", "Usage Extraction Operational Stats")
         for audit_event in usage_state.standalone_events():
             try:
                 operational_wu = self._create_operation_workunit(
@@ -381,7 +426,7 @@ class BigQueryUsageExtractor:
     def _generate_usage_workunits(
         self, usage_state: BigQueryUsageState
     ) -> Iterable[MetadataWorkUnit]:
-        self.report.set_project_state("All", "Usage Extraction Usage Aggregation")
+        self.report.set_ingestion_stage("*", "Usage Extraction Usage Aggregation")
         top_n = (
             self.config.usage.top_n_queries
             if self.config.usage.include_top_n_queries
@@ -389,11 +434,20 @@ class BigQueryUsageExtractor:
         )
         for entry in usage_state.usage_statistics(top_n=top_n):
             try:
+                query_freq = [
+                    (
+                        self.uuid_to_query.get(
+                            query_hash, usage_state.queries[query_hash]
+                        ),
+                        count,
+                    )
+                    for query_hash, count in entry.query_freq
+                ]
                 yield make_usage_workunit(
                     bucket_start_time=datetime.fromisoformat(entry.timestamp),
                     resource=BigQueryTableRef.from_string_name(entry.resource),
                     query_count=entry.query_count,
-                    query_freq=entry.query_freq,
+                    query_freq=query_freq,
                     user_freq=entry.user_freq,
                     column_freq=entry.column_freq,
                     bucket_duration=self.config.bucket_duration,
@@ -416,7 +470,7 @@ class BigQueryUsageExtractor:
         for project_id in projects:
             with PerfTimer() as timer:
                 try:
-                    self.report.set_project_state(
+                    self.report.set_ingestion_stage(
                         project_id, "Usage Extraction Ingestion"
                     )
                     yield from self._get_parsed_bigquery_log_events(project_id)
@@ -460,6 +514,16 @@ class BigQueryUsageExtractor:
                 usage_state.column_accesses[str(uuid.uuid4())] = key, field_read
             return True
         elif event.query_event and event.query_event.job_name:
+            query = event.query_event.query[:MAX_QUERY_LENGTH]
+            query_hash = hashlib.md5(query.encode(STRING_ENCODING)).hexdigest()
+            if usage_state.queries.get(query_hash, query) != query:
+                key = str(uuid.uuid4())
+                self.uuid_to_query[key] = query
+                event.query_event.query = key
+                self.report.num_usage_query_hash_collisions += 1
+            else:
+                usage_state.queries[query_hash] = query
+                event.query_event.query = query_hash
             usage_state.query_events[event.query_event.job_name] = event.query_event
             return True
         return False

metadata-ingestion/src/datahub/utilities/file_backed_collections.py

@@ -1,4 +1,5 @@
 import collections
+import gzip
 import logging
 import pathlib
 import pickle
@@ -153,8 +154,11 @@ class FileBackedDict(MutableMapping[str, _VT], Generic[_VT], Closeable):
 
     cache_max_size: int = _DEFAULT_MEMORY_CACHE_MAX_SIZE
     cache_eviction_batch_size: int = _DEFAULT_MEMORY_CACHE_EVICTION_BATCH_SIZE
+    delay_index_creation: bool = False
+    should_compress_value: bool = False
 
     _conn: ConnectionWrapper = field(init=False, repr=False)
+    indexes_created: bool = field(init=False, default=False)
 
     # To improve performance, we maintain an in-memory LRU cache using an OrderedDict.
     # Maintains a dirty bit marking whether the value has been modified since it was persisted.
@@ -190,12 +194,24 @@ class FileBackedDict(MutableMapping[str, _VT], Generic[_VT], Closeable):
             )"""
         )
 
-        # The key column will automatically be indexed, but we need indexes
+        if not self.delay_index_creation:
-        # for the extra columns.
+            self.create_indexes()
+
+        if self.should_compress_value:
+            serializer = self.serializer
+            self.serializer = lambda value: gzip.compress(serializer(value))  # type: ignore
+            deserializer = self.deserializer
+            self.deserializer = lambda value: deserializer(gzip.decompress(value))
+
+    def create_indexes(self) -> None:
+        if self.indexes_created:
+            return
+        # The key column will automatically be indexed, but we need indexes for the extra columns.
         for column_name in self.extra_columns.keys():
             self._conn.execute(
                 f"CREATE INDEX {self.tablename}_{column_name} ON {self.tablename} ({column_name})"
             )
+        self.indexes_created = True
 
     def _add_to_cache(self, key: str, value: _VT, dirty: bool) -> None:
         self._active_object_cache[key] = value, dirty
@@ -377,7 +393,7 @@ class FileBackedList(Generic[_VT]):
         cache_eviction_batch_size: Optional[int] = None,
     ) -> None:
         self._len = 0
-        self._dict = FileBackedDict(
+        self._dict = FileBackedDict[_VT](
             shared_connection=connection,
             serializer=serializer,
             deserializer=deserializer,

metadata-ingestion/tests/performance/README.md

@@ -1,7 +1,6 @@
 # Performance Testing
 This module provides a framework for performance testing our ingestion sources.
 
-When running a performance test, make sure to output print statements and live logs:
 ```bash
-pytest -s --log-cli-level=INFO -m performance tests/performance/<test_name>.py
+python -m tests.performance.<test_name>
 ```

metadata-ingestion/tests/performance/data_generation.py

@@ -13,6 +13,8 @@ from dataclasses import dataclass
 from datetime import datetime, timedelta, timezone
 from typing import Iterable, List, TypeVar
 
+from faker import Faker
+
 from tests.performance.data_model import (
     Container,
     FieldAccess,
@@ -106,12 +108,19 @@ def generate_queries(
     seed_metadata: SeedMetadata,
     num_selects: int,
     num_operations: int,
+    num_unique_queries: int,
     num_users: int,
     tables_per_select: NormalDistribution = NormalDistribution(3, 5),
     columns_per_select: NormalDistribution = NormalDistribution(10, 5),
     upstream_tables_per_operation: NormalDistribution = NormalDistribution(2, 2),
     query_length: NormalDistribution = NormalDistribution(100, 50),
 ) -> Iterable[Query]:
+    faker = Faker()
+    query_texts = [
+        faker.paragraph(query_length.sample_with_floor(30) // 30)
+        for _ in range(num_unique_queries)
+    ]
+
     all_tables = seed_metadata.tables + seed_metadata.views
     users = [f"user-{i}@xyz.com" for i in range(num_users)]
     for i in range(num_selects):  # Pure SELECT statements
@@ -120,7 +129,7 @@ def generate_queries(
             FieldAccess(column, table) for table in tables for column in table.columns
         ]
         yield Query(
-            text=f"{uuid.uuid4()}-{'*' * query_length.sample_with_floor(10)}",
+            text=random.choice(query_texts),
             type="SELECT",
             actor=random.choice(users),
             timestamp=_random_time_between(
@@ -141,7 +150,7 @@ def generate_queries(
             for column in table.columns
         ]
         yield Query(
-            text=f"{uuid.uuid4()}-{'*' * query_length.sample_with_floor(10)}",
+            text=random.choice(query_texts),
             type=random.choice(OPERATION_TYPES),
             actor=random.choice(users),
             timestamp=_random_time_between(

metadata-ingestion/tests/performance/test_bigquery_usage.py

@@ -2,41 +2,35 @@ import logging
 import os
 import random
 from datetime import timedelta
+from typing import Iterable, Tuple
 
 import humanfriendly
 import psutil
-import pytest
 
+from datahub.ingestion.api.workunit import MetadataWorkUnit
 from datahub.ingestion.source.bigquery_v2.bigquery_config import (
     BigQueryUsageConfig,
     BigQueryV2Config,
 )
-from datahub.ingestion.source.bigquery_v2.bigquery_report import (
+from datahub.ingestion.source.bigquery_v2.bigquery_report import BigQueryV2Report
-    BigQueryV2Report,
-    logger as report_logger,
-)
 from datahub.ingestion.source.bigquery_v2.usage import BigQueryUsageExtractor
 from datahub.utilities.perf_timer import PerfTimer
 from tests.performance.bigquery import generate_events, ref_from_table
-from tests.performance.data_generation import generate_data, generate_queries
+from tests.performance.data_generation import (
-
+    NormalDistribution,
-pytestmark = pytest.mark.performance
+    generate_data,
+    generate_queries,
+)
 
 
-@pytest.fixture(autouse=True)
+def run_test():
-def report_log_level_info(caplog):
-    with caplog.at_level(logging.INFO, logger=report_logger.name):
-        yield
-
-
-def test_bigquery_usage(report_log_level_info):
     report = BigQueryV2Report()
-    report.set_project_state("All", "Seed Data Generation")
+    report.set_ingestion_stage("All", "Seed Data Generation")
     seed_metadata = generate_data(
-        num_containers=100,
+        num_containers=2000,
-        num_tables=2500,
+        num_tables=20000,
-        num_views=100,
+        num_views=2000,
-        time_range=timedelta(days=1),
+        time_range=timedelta(days=7),
     )
     all_tables = seed_metadata.tables + seed_metadata.views
 
@@ -44,33 +38,64 @@ def test_bigquery_usage(report_log_level_info):
         start_time=seed_metadata.start_time,
         end_time=seed_metadata.end_time,
         usage=BigQueryUsageConfig(include_top_n_queries=True, top_n_queries=10),
+        file_backed_cache_size=1000,
     )
     usage_extractor = BigQueryUsageExtractor(config, report)
-    report.set_project_state("All", "Event Generation")
+    report.set_ingestion_stage("All", "Event Generation")
 
-    num_projects = 5
+    num_projects = 100
     projects = [f"project-{i}" for i in range(num_projects)]
     table_to_project = {table.name: random.choice(projects) for table in all_tables}
     table_refs = {str(ref_from_table(table, table_to_project)) for table in all_tables}
 
-    queries = generate_queries(
+    queries = list(
-        seed_metadata,
+        generate_queries(
-        num_selects=30000,
+            seed_metadata,
-        num_operations=20000,
+            num_selects=240_000,
-        num_users=10,
+            num_operations=800_000,
+            num_unique_queries=50_000,
+            num_users=2000,
+            query_length=NormalDistribution(2000, 500),
+        )
     )
-    events = generate_events(queries, projects, table_to_project, config=config)
+    queries.sort(key=lambda q: q.timestamp)
-    events = list(events)
+    events = list(generate_events(queries, projects, table_to_project, config=config))
     print(f"Events generated: {len(events)}")
+    pre_mem_usage = psutil.Process(os.getpid()).memory_info().rss
+    print(f"Test data size: {humanfriendly.format_size(pre_mem_usage)}")
 
-    report.set_project_state("All", "Event Ingestion")
+    report.set_ingestion_stage("All", "Event Ingestion")
     with PerfTimer() as timer:
         workunits = usage_extractor._run(events, table_refs)
-        num_workunits = sum(1 for _ in workunits)
+        num_workunits, peak_memory_usage = workunit_sink(workunits)
-        report.set_project_state("All", "Done")
+        report.set_ingestion_stage("All", "Done")
         print(f"Workunits Generated: {num_workunits}")
         print(f"Seconds Elapsed: {timer.elapsed_seconds():.2f} seconds")
 
     print(
-        f"Memory Used: {humanfriendly.format_size(psutil.Process(os.getpid()).memory_info().rss)}"
+        f"Peak Memory Used: {humanfriendly.format_size(peak_memory_usage - pre_mem_usage)}"
     )
+    print(f"Disk Used: {report.usage_state_size}")
+    print(f"Hash collisions: {report.num_usage_query_hash_collisions}")
+
+
+def workunit_sink(workunits: Iterable[MetadataWorkUnit]) -> Tuple[int, int]:
+    peak_memory_usage = psutil.Process(os.getpid()).memory_info().rss
+    i: int = 0
+    for i, wu in enumerate(workunits):
+        if i % 10_000 == 0:
+            peak_memory_usage = max(
+                peak_memory_usage, psutil.Process(os.getpid()).memory_info().rss
+            )
+    peak_memory_usage = max(
+        peak_memory_usage, psutil.Process(os.getpid()).memory_info().rss
+    )
+
+    return i, peak_memory_usage
+
+
+if __name__ == "__main__":
+    root_logger = logging.getLogger()
+    root_logger.setLevel(logging.INFO)
+    root_logger.addHandler(logging.StreamHandler())
+    run_test()

metadata-ingestion/tests/unit/test_bigquery_usage.py

@@ -396,8 +396,8 @@ def test_usage_counts_multiple_buckets_and_resources(
                 totalSqlQueries=4,
                 topSqlQueries=[
                     query_table_1_a().text,
-                    query_table_1_b().text,
                     query_tables_1_and_2().text,
+                    query_table_1_b().text,
                 ],
                 uniqueUserCount=2,
                 userCounts=[
@@ -471,7 +471,7 @@ def test_usage_counts_multiple_buckets_and_resources(
                     unit=BucketDuration.DAY, multiple=1
                 ),
                 totalSqlQueries=2,
-                topSqlQueries=[query_table_2().text, query_tables_1_and_2().text],
+                topSqlQueries=[query_tables_1_and_2().text, query_table_2().text],
                 uniqueUserCount=1,
                 userCounts=[
                     DatasetUserUsageCountsClass(
@@ -614,6 +614,7 @@ def test_operational_stats(
             seed_metadata,
             num_selects=10,
             num_operations=20,
+            num_unique_queries=10,
             num_users=3,
         )
     )