datalens-tech/datalens-backend
Dec 2024 – Mar 2026
15 Months active
Languages Used
PythonTOMLDockerfileSQLYAMLJSON
Technical Skills
Backend DevelopmentDatabase ConnectivityDatabase ConnectorsDatabase ManagementDockerMySQL
Denis Khamitov
PROFILE
Denis Khamitov
Over 15 months, Damir Khamitov developed and maintained core backend features for the datalens-tech/datalens-backend repository, focusing on secure, scalable data access and analytics. He engineered robust Trino and MySQL connectors, implemented authentication flows, and enhanced API and schema design to support flexible, metadata-rich integrations. Using Python, SQL, and Docker, Damir delivered features such as cross-database hash functions, advanced formula engines, and asynchronous authentication, while strengthening test automation and deployment reliability. His work emphasized maintainability through modular refactoring, comprehensive testing, and configuration management, resulting in a backend platform that supports secure, high-performance analytics and streamlined developer operations.
Overall Statistics
Feature vs Bugs
84%Features
Repository Contributions
148Total
Bugs
11
Commits
148
Features
56
Lines of code
17,451
Activity Months15
Your Network
126 peopleSame Organization
@yandex-team.ru113
Work History
March 2026
5 Commits • 3 Features
Mar 1, 2026Monthly summary for 2026-03 for datalens-backend: Delivered key asynchronous authentication and US management improvements, introduced per-request USAuthContext for file uploads, updated deployment/docker environment, and fixed critical checks in US manager creation. These efforts enable non-blocking authentication, improved security through per-request contexts, streamlined testing with dev Docker configurations, and more reliable US service initialization, driving faster response times, safer access controls, and clearer logging.
5 Commits • 3 Features
Mar 1, 2026Monthly summary for 2026-03 for datalens-backend: Delivered key asynchronous authentication and US management improvements, introduced per-request USAuthContext for file uploads, updated deployment/docker environment, and fixed critical checks in US manager creation. These efforts enable non-blocking authentication, improved security through per-request contexts, streamlined testing with dev Docker configurations, and more reliable US service initialization, driving faster response times, safer access controls, and clearer logging.
March 2026
February 2026
5 Commits • 2 Features
Feb 1, 2026February 2026 monthly summary for datalens-backend focused on strengthening authentication, improving maintainability, and stabilizing build configurations to support secure, scalable back-end operations. Key business value: hardened authentication and streamlined deployment readiness reduce risk for client integrations and accelerate feature delivery pipelines.
February 2026
5 Commits • 2 Features
Feb 1, 2026February 2026 monthly summary for datalens-backend focused on strengthening authentication, improving maintainability, and stabilizing build configurations to support secure, scalable back-end operations. Key business value: hardened authentication and streamlined deployment readiness reduce risk for client integrations and accelerate feature delivery pipelines.
January 2026
2 Commits • 1 Features
Jan 1, 2026January 2026 (2026-01) backend authentication enhancements in datalens-backend focused on observability, environment-specific authentication flows, and modular middleware initialization. Delivered a cohesive feature combining two commits to enhance traceability and future environment support; prepared the codebase for multi-env deployments.
2 Commits • 1 Features
Jan 1, 2026January 2026 (2026-01) backend authentication enhancements in datalens-backend focused on observability, environment-specific authentication flows, and modular middleware initialization. Delivered a cohesive feature combining two commits to enhance traceability and future environment support; prepared the codebase for multi-env deployments.
January 2026
December 2025
10 Commits • 4 Features
Dec 1, 2025December 2025 Monthly Summary for datalens-backend: Delivered performance and security improvements, expanded analytics capabilities, and strengthened maintainability across the repo. The work enabled faster queries, broader formula capabilities, and safer DB_CALL usage, while keeping a strong focus on code quality and documentation to support ongoing delivery and onboarding.
December 2025
10 Commits • 4 Features
Dec 1, 2025December 2025 Monthly Summary for datalens-backend: Delivered performance and security improvements, expanded analytics capabilities, and strengthened maintainability across the repo. The work enabled faster queries, broader formula capabilities, and safer DB_CALL usage, while keeping a strong focus on code quality and documentation to support ongoing delivery and onboarding.
November 2025
1 Commits • 1 Features
Nov 1, 2025November 2025 monthly summary for datalens-backend: Implemented Cross-Database Hash Function Support across ClickHouse, MySQL, PostgreSQL, Oracle, YDB, and Trino, enabling MD5, SHA1, SHA256, and other hash variants across database connectors. Introduced base tests and an expanded testing framework with fixtures and configurations to ensure compatibility and correctness across connectors. Applied Oracle-specific hashing fixes (pass hash name as literal; UTL_RAW.CAST_TO_RAW) and moved multiple-argument hash tests to ClickHouse for maintainability. Result: improved data integrity and consistent hashing across databases, reducing risk in migrations and analytics pipelines. Technologies demonstrated: multi-database integration, cryptographic hashing, fixture-driven testing, test automation, and CI-ready quality.
1 Commits • 1 Features
Nov 1, 2025November 2025 monthly summary for datalens-backend: Implemented Cross-Database Hash Function Support across ClickHouse, MySQL, PostgreSQL, Oracle, YDB, and Trino, enabling MD5, SHA1, SHA256, and other hash variants across database connectors. Introduced base tests and an expanded testing framework with fixtures and configurations to ensure compatibility and correctness across connectors. Applied Oracle-specific hashing fixes (pass hash name as literal; UTL_RAW.CAST_TO_RAW) and moved multiple-argument hash tests to ClickHouse for maintainability. Result: improved data integrity and consistent hashing across databases, reducing risk in migrations and analytics pipelines. Technologies demonstrated: multi-database integration, cryptographic hashing, fixture-driven testing, test automation, and CI-ready quality.
November 2025
October 2025
9 Commits • 5 Features
Oct 1, 2025October 2025 — datalens-backend monthly summary. Key features delivered: - Trino Query Timeout Support: added query_max_run_time session property to Trino connections, improved error handling by mapping Trino timeout errors to a SourceTimeout exception, and added tests to verify timeout behavior (commit dd98acde926ef0be58deae085d5f6dd360fe834b). - Form Description Field Enhancements: introduced a hidden description field across all forms to capture metadata; updated API schema and base form configurations; supports optional description on create/edit; accompanied by multiple commits to iterate on the feature (9a3b8515160b3c12a5b5723c9058865563da4358; 5724490ee583a93f15de7143f66c2e41891d0333; 626d775d54ae2324ea05a4dcf59f5741d4c1a7b3). - DB_CALL and DB_CALL_AGG across Connectors: added native DB_CALL functions across connectors and introduced aggregated variants (DB_CALL_AGG_INT/FLOAT/STRING); extensive tests across multiple data sources (commits 44efe0601d9c8ee68f90f211a5ab8b9cab1eeb6e; fc306afb8018ccc6fc696803da3f4c142cde8310). - Secure Reader Logging: implemented logging enhancements for the file secure reader to improve error tracking and debugging (commit 2feb9ffd832807fb0fe3f7c89ec54d94f268df53). - YaDocs Excel Patch Bug Fix: temporary patch for openpyxl to correct broken styles in YaDocs Excel files with tests verifying alignment behavior (commit 84ea56b2a15387b7d79ef87d0edd49ebdf875db9). - Dependency Lockfile Maintenance: updated poetry.lock to reflect dependency changes and removed obsolete entries to ensure dependency integrity (commit e09752dd4b6e69244fe30c987fdde674a517d3f8). Major bugs fixed: - YaDocs Excel patch for broken styles resolved with tests (BI-6635). - Minor API schema adjustment to make description field optional (described in related commits). Overall impact and accomplishments: - Significantly improved reliability of long-running Trino queries and overall query resilience. - Enhanced metadata capture and form configurability across the platform, enabling better data governance. - Expanded native database capabilities across connectors with consistent tests, enabling richer analytics and faster development cycles. - Improved observability and debugging through enhanced logging, reducing MTTR. - Strengthened build determinism and dependency integrity through lockfile maintenance, reducing deployment risks.
October 2025
9 Commits • 5 Features
Oct 1, 2025October 2025 — datalens-backend monthly summary. Key features delivered: - Trino Query Timeout Support: added query_max_run_time session property to Trino connections, improved error handling by mapping Trino timeout errors to a SourceTimeout exception, and added tests to verify timeout behavior (commit dd98acde926ef0be58deae085d5f6dd360fe834b). - Form Description Field Enhancements: introduced a hidden description field across all forms to capture metadata; updated API schema and base form configurations; supports optional description on create/edit; accompanied by multiple commits to iterate on the feature (9a3b8515160b3c12a5b5723c9058865563da4358; 5724490ee583a93f15de7143f66c2e41891d0333; 626d775d54ae2324ea05a4dcf59f5741d4c1a7b3). - DB_CALL and DB_CALL_AGG across Connectors: added native DB_CALL functions across connectors and introduced aggregated variants (DB_CALL_AGG_INT/FLOAT/STRING); extensive tests across multiple data sources (commits 44efe0601d9c8ee68f90f211a5ab8b9cab1eeb6e; fc306afb8018ccc6fc696803da3f4c142cde8310). - Secure Reader Logging: implemented logging enhancements for the file secure reader to improve error tracking and debugging (commit 2feb9ffd832807fb0fe3f7c89ec54d94f268df53). - YaDocs Excel Patch Bug Fix: temporary patch for openpyxl to correct broken styles in YaDocs Excel files with tests verifying alignment behavior (commit 84ea56b2a15387b7d79ef87d0edd49ebdf875db9). - Dependency Lockfile Maintenance: updated poetry.lock to reflect dependency changes and removed obsolete entries to ensure dependency integrity (commit e09752dd4b6e69244fe30c987fdde674a517d3f8). Major bugs fixed: - YaDocs Excel patch for broken styles resolved with tests (BI-6635). - Minor API schema adjustment to make description field optional (described in related commits). Overall impact and accomplishments: - Significantly improved reliability of long-running Trino queries and overall query resilience. - Enhanced metadata capture and form configurability across the platform, enabling better data governance. - Expanded native database capabilities across connectors with consistent tests, enabling richer analytics and faster development cycles. - Improved observability and debugging through enhanced logging, reducing MTTR. - Strengthened build determinism and dependency integrity through lockfile maintenance, reducing deployment risks.
September 2025
13 Commits • 6 Features
Sep 1, 2025Monthly summary for 2025-09 focusing on metadata-driven features, reliability improvements, and robust testing. Key outcomes include the introduction of description fields for connections and datasets with API update support, enhanced Trino timeout controls, dataset copy functionality, and expanded testing utilities. The work improves data governance, developer experience, and system reliability by enabling richer metadata, safer data duplication, and more trustworthy integrations.
13 Commits • 6 Features
Sep 1, 2025Monthly summary for 2025-09 focusing on metadata-driven features, reliability improvements, and robust testing. Key outcomes include the introduction of description fields for connections and datasets with API update support, enhanced Trino timeout controls, dataset copy functionality, and expanded testing utilities. The work improves data governance, developer experience, and system reliability by enabling richer metadata, safer data duplication, and more trustworthy integrations.
September 2025
August 2025
5 Commits • 2 Features
Aug 1, 2025August 2025 monthly summary for datalens-backend: Focused on hardening Trino authentication integration and simplifying test infrastructure, delivering configurable authentication, schema improvements, and faster, more reliable tests.
August 2025
5 Commits • 2 Features
Aug 1, 2025August 2025 monthly summary for datalens-backend: Focused on hardening Trino authentication integration and simplifying test infrastructure, delivering configurable authentication, schema improvements, and faster, more reliable tests.
July 2025
8 Commits • 3 Features
Jul 1, 2025July 2025 monthly summary for datalens-backend: Focused on stabilizing and extending Trino integration through targeted refactors, configurability, and security improvements. Business value centers on safer, more maintainable connectors and improved user-facing configuration.
8 Commits • 3 Features
Jul 1, 2025July 2025 monthly summary for datalens-backend: Focused on stabilizing and extending Trino integration through targeted refactors, configurability, and security improvements. Business value centers on safer, more maintainable connectors and improved user-facing configuration.
July 2025
June 2025
17 Commits • 9 Features
Jun 1, 2025June 2025 monthly summary for datalens-backend focusing on Trino dialect and backend enhancements. Delivered significant query and connector capabilities, improved stability and typing, and strengthened security and test infrastructure. These efforts expand user-facing features, reduce runtime errors, and accelerate development velocity across the Trino-facing stack.
June 2025
17 Commits • 9 Features
Jun 1, 2025June 2025 monthly summary for datalens-backend focusing on Trino dialect and backend enhancements. Delivered significant query and connector capabilities, improved stability and typing, and strengthened security and test infrastructure. These efforts expand user-facing features, reduce runtime errors, and accelerate development velocity across the Trino-facing stack.
May 2025
7 Commits • 2 Features
May 1, 2025May 2025 focused on delivering a robust Trino-based data access layer and standardizing deployment for the US service in datalens-backend. Key features shipped include a Trino Connector Core with data access capabilities and a richer connection experience (JWT/SSL, subselect data sources) plus broader deployment configuration standardization across environments. These efforts were implemented through multiple commits across the Trino-related workstream and deployment fixes, enabling more reliable BI data access and faster feature delivery.
7 Commits • 2 Features
May 1, 2025May 2025 focused on delivering a robust Trino-based data access layer and standardizing deployment for the US service in datalens-backend. Key features shipped include a Trino Connector Core with data access capabilities and a richer connection experience (JWT/SSL, subselect data sources) plus broader deployment configuration standardization across environments. These efforts were implemented through multiple commits across the Trino-related workstream and deployment fixes, enabling more reliable BI data access and faster feature delivery.
May 2025
April 2025
18 Commits • 5 Features
Apr 1, 2025April 2025 monthly summary for datalens-backend: Focused on delivering a robust Trino formula connector with expanded data transformation capabilities, comprehensive analytics functions, and improved reliability. Delivered core features across data transformation, date/time handling, and analytics inside Trino formulas, along with a major reliability and testing uplift. Implemented core data transformation functions (string, array, custom constructors, lambda, and markup) and expanded DateTime/temporal support with timezone-aware operations, plus analytics, math, aggregation, and window functions. Strengthened testing and infrastructure for Trino formulas, improving coverage and reliability. Fixed critical issues in Trino DefaultAdapter to ensure accurate server version retrieval, and completed a core refactor to centralize catalog/schema handling for maintainability and correctness. Business value: enables richer in-database transformations, tighter data correctness, faster iteration with stronger tests, and reduced operational risk.
April 2025
18 Commits • 5 Features
Apr 1, 2025April 2025 monthly summary for datalens-backend: Focused on delivering a robust Trino formula connector with expanded data transformation capabilities, comprehensive analytics functions, and improved reliability. Delivered core features across data transformation, date/time handling, and analytics inside Trino formulas, along with a major reliability and testing uplift. Implemented core data transformation functions (string, array, custom constructors, lambda, and markup) and expanded DateTime/temporal support with timezone-aware operations, plus analytics, math, aggregation, and window functions. Strengthened testing and infrastructure for Trino formulas, improving coverage and reliability. Fixed critical issues in Trino DefaultAdapter to ensure accurate server version retrieval, and completed a core refactor to centralize catalog/schema handling for maintainability and correctness. Business value: enables richer in-database transformations, tighter data correctness, faster iteration with stronger tests, and reduced operational risk.
March 2025
32 Commits • 8 Features
Mar 1, 2025March 2025: Trino integration and testing enhancements across datalens-backend delivered improved reliability, faster CI feedback, and stronger business value for BI workflows. Implemented robust BI-0 test infrastructure with UUID formatting normalization, optional schema support, log prettification, and gating adjustments; advanced BI-5355 integration including parse_sqltype usage, TrinoDialect adapter refactor, and a new connection executor and datasource; expanded BI-5355 test utilities with dataset and RQE tests; elevated Trino formula connector capabilities (literals, operators, conditionals, DB_CAST) plus array support and comprehensive type conversions; and targeted stability fixes (TargetDTO deserialisation, skipping tests, and argument-type corrections) to improve release quality.
32 Commits • 8 Features
Mar 1, 2025March 2025: Trino integration and testing enhancements across datalens-backend delivered improved reliability, faster CI feedback, and stronger business value for BI workflows. Implemented robust BI-0 test infrastructure with UUID formatting normalization, optional schema support, log prettification, and gating adjustments; advanced BI-5355 integration including parse_sqltype usage, TrinoDialect adapter refactor, and a new connection executor and datasource; expanded BI-5355 test utilities with dataset and RQE tests; elevated Trino formula connector capabilities (literals, operators, conditionals, DB_CAST) plus array support and comprehensive type conversions; and targeted stability fixes (TargetDTO deserialisation, skipping tests, and argument-type corrections) to improve release quality.
March 2025
February 2025
11 Commits • 3 Features
Feb 1, 2025February 2025 monthly summary for datalens-backend focusing on delivering a robust Trino-backed data access layer, improving data ingestion performance, and hardening test infrastructure. Highlights cover delivering the Trino core connector with authentication, SSL/TLS, and adapter/executor integration; bulk insert optimizations; and CSV/Oracle naming enhancements, underpinned by strengthened test stability and environment setup.
February 2025
11 Commits • 3 Features
Feb 1, 2025February 2025 monthly summary for datalens-backend focusing on delivering a robust Trino-backed data access layer, improving data ingestion performance, and hardening test infrastructure. Highlights cover delivering the Trino core connector with authentication, SSL/TLS, and adapter/executor integration; bulk insert optimizations; and CSV/Oracle naming enhancements, underpinned by strengthened test stability and environment setup.
December 2024
5 Commits • 2 Features
Dec 1, 2024December 2024: Datalens backend delivered security hardening for MySQL connections and strengthened test reliability. Implemented TLS/SSL support across MySQL connections, added SSL configuration fields to the connection schema, updated adapters to use SSL contexts, and enforced secure default SSL behavior in connectors. Improved test infrastructure by simplifying SSL error checks and ensuring real connection entries are used in tests, boosting reliability. These changes enhance data-in-transit security, reduce production risk from misconfigurations, and demonstrate strong capabilities in TLS/SSL integration, schema evolution, and test automation.
5 Commits • 2 Features
Dec 1, 2024December 2024: Datalens backend delivered security hardening for MySQL connections and strengthened test reliability. Implemented TLS/SSL support across MySQL connections, added SSL configuration fields to the connection schema, updated adapters to use SSL contexts, and enforced secure default SSL behavior in connectors. Improved test infrastructure by simplifying SSL error checks and ensuring real connection entries are used in tests, boosting reliability. These changes enhance data-in-transit security, reduce production risk from misconfigurations, and demonstrate strong capabilities in TLS/SSL integration, schema evolution, and test automation.
December 2024
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Quality Metrics
Correctness89.2%
Maintainability87.8%
Architecture85.4%
Performance80.6%
AI Usage21.8%
Skills & Technologies
Programming Languages
DockerfileJSONPythonSQLTOMLYAML
Technical Skills
API ConfigurationAPI DesignAPI DevelopmentAPI IntegrationAPI TestingAPI designAPI developmentAuthenticationBackend DevelopmentBug FixingCI/CDCode ReusabilityCode StyleConfiguration ManagementConnector Development
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