V3 spanner mux session default

[scotthart]

This change is 

[gemini-code-assist]

Summary of Changes

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This pull request introduces a significant change to the Google Cloud Spanner C++ client library by making multiplexed sessions the default operational mode. This streamlines the user experience by eliminating the need for explicit configuration of multiplexing and deprecating various session pool options that are no longer relevant. The changes also include comprehensive updates to tests and examples to ensure they align with this new default behavior, enhancing code consistency and maintainability.

Highlights

• Default Multiplexed Sessions: Multiplexed sessions are now enabled by default in the Google Cloud Spanner C++ client library, simplifying session management for users.
• Deprecation of Session Pool Options: Several session pool configuration options, such as minimum/maximum sessions, action on exhaustion, and keep-alive interval, have been deprecated as they are no longer applicable with the default multiplexed session behavior.
• Test and Example Alignment: Spanner tests and examples have been updated to reflect the new default, removing explicit multiplexed session enablement and adapting to the single multiplexed session model, along with general cleanup of irrelevant session pool tests.
• C++ Style Refinement: A minor C++ style change was applied in Bigtable snippets, modifying a function parameter to be passed by const& for better practice.

Changelog

• google/cloud/bigtable/examples/table_admin_snippets.cc
  • Changed BigtableTableAdminClient admin to BigtableTableAdminClient const& admin in WaitForConsistencyCheck function signature and a lambda.
• google/cloud/spanner/README.md
  • Added includes for disabling and re-enabling deprecation warnings around the quickstart code snippet.
• google/cloud/spanner/admin/integration_tests/backup_extra_integration_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/admin/integration_tests/backup_integration_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/benchmarks/multiple_rows_cpu_benchmark.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/benchmarks/single_row_throughput_benchmark.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/client.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/client_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/commit_options.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/connection.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/integration_tests/client_integration_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/integration_tests/client_stress_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/integration_tests/data_types_integration_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/integration_tests/session_pool_integration_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/internal/connection_impl.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/internal/defaults.cc
  • Enabled multiplexed sessions by default using spanner::EnableMultiplexedSessionOption.
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/internal/defaults_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/internal/partial_result_set_resume_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/internal/partial_result_set_source.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/internal/partial_result_set_source_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/internal/route_to_leader.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/internal/route_to_leader_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/internal/session_pool.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/internal/session_pool_test.cc
  • Removed unused TextFormat, StrictMock, and UnorderedElementsAre using declarations.
  • Removed MakeSessionsResponse helper function.
  • Updated MakeTestSessionPool calls to remove explicit EnableMultiplexedSessionOption setting.
  • Modified test cases to use pool->Multiplexed() instead of pool->Allocate().
  • Changed BatchCreateSessions expectations to CreateSession with IsMultiplexed() matcher.
  • Removed several tests related to non-multiplexed session pool behavior (e.g., ReleaseBadSession, Lifo, MinSessionsEagerAllocation, MaxSessionsFailOnExhaustion, SessionRefresh).
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/options.h
  • Deprecated EnableMultiplexedSessionOption as multiplexed sessions are now always enabled.
  • Deprecated SessionPoolMinSessionsOption, SessionPoolMaxSessionsPerChannelOption, SessionPoolMaxIdleSessionsOption, ActionOnExhaustion enum, SessionPoolActionOnExhaustionOption, and SessionPoolKeepAliveIntervalOption as they are not used with multiplexed sessions.
  • Updated SessionPoolOptionList to remove the deprecated options.
• google/cloud/spanner/partition_options.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/query_options.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/query_options_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/query_partition.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/query_partition_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/quickstart/quickstart.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/read_options.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/read_partition.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/read_partition_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/results_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/samples/client_samples.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/samples/graph_samples.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/samples/mock_execute_query.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/samples/postgresql_samples.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/samples/samples.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/session_pool_options_test.cc
  • Added includes for disabling and re-enabling deprecation warnings.
• google/cloud/spanner/transaction.cc
  • Added includes for disabling and re-enabling deprecation warnings.

Activity

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[gemini-code-assist]

Code Review

This pull request updates the Spanner client to enable multiplexed sessions by default, deprecating several session pool options that are no longer relevant in this new model. It also includes minor C++ style improvements in Bigtable examples and adjusts Spanner tests to reflect the new session management strategy. The changes are consistent with the goal of simplifying session handling by making multiplexed sessions the standard.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.62%. Comparing base (e1d9216) to head (8b3bd0b).
⚠️ Report is 2 commits behind head on prepare-for-v3.0.0.

Additional details and impacted files

@@                  Coverage Diff                   @@
##           prepare-for-v3.0.0   #15934      +/-   ##
======================================================
- Coverage               92.79%   92.62%   -0.18%     
======================================================
  Files                    2332     2332              
  Lines                  214386   213386    -1000     
======================================================
- Hits                   198946   197651    -1295     
- Misses                  15440    15735     +295     

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