- 关于MogDB
- 快速入门
- 安装指南
- 管理指南
- 日常运维
- 主备管理
- 高可用管理
- MOT内存表管理
- 列存表管理
- 备份与恢复
- 数据导出导入
- 升级指南
- 常见故障处理指南
- 常见故障定位手段
- 常见故障定位案例
- core问题定位
- TPCC运行时,注入磁盘满故障,TPCC卡住的问题
- 备机处于need repair(WAL)状态问题
- 内存不足问题
- 服务启动失败
- 出现“Error:No space left on device”提示
- 在XFS文件系统中,使用du命令查询数据文件大小大于文件实际大小
- 在XFS文件系统中,出现文件损坏
- switchover操作时,主机降备卡住
- 磁盘空间达到阈值,数据库只读
- 分析查询语句长时间运行的问题
- 分析查询语句运行状态
- 强制结束指定的问题会话
- 分析查询语句是否被阻塞
- 分析查询效率异常降低的问题
- 执行 SQL 语句时,提示 Lock wait timeout
- VACUUM FULL一张表后,表文件大小无变化
- 执行修改表分区操作时报错
- 不同用户查询同表显示数据不同
- 修改索引时只调用索引名提示索引不存在
- 重建索引失败
- 业务运行时整数转换错
- 高并发报错”too many clients already”或无法创建线程
- btree 索引故障情况下应对策略
- 安全指南
- 性能优化指南
- 开发者指南
- 参考指南
- 系统表及系统视图
- 系统表和系统视图概述
- 系统表
- GS_CLIENT_GLOBAL_KEYS
- GS_CLIENT_GLOBAL_KEYS_ARGS
- GS_COLUMN_KEYS
- GS_COLUMN_KEYS_ARGS
- GS_ENCRYPTED_COLUMNS
- GS_OPT_MODEL
- GS_WLM_INSTANCE_HISTORY
- GS_WLM_OPERATOR_INFO
- GS_WLM_PLAN_ENCODING_TABLE
- GS_WLM_PLAN_OPERATOR_INFO
- GS_WLM_USER_RESOURCE_HISTORY
- PG_AGGREGATE
- PG_AM
- PG_AMOP
- PG_AMPROC
- PG_APP_WORKLOADGROUP_MAPPING
- PG_ATTRDEF
- PG_ATTRIBUTE
- PG_AUTHID
- PG_AUTH_HISTORY
- PG_AUTH_MEMBERS
- PG_CAST
- PG_CLASS
- PG_COLLATION
- PG_CONSTRAINT
- PG_CONVERSION
- PG_DATABASE
- PG_DB_ROLE_SETTING
- PG_DEFAULT_ACL
- PG_DEPEND
- PG_DESCRIPTION
- PG_DIRECTORY
- PG_ENUM
- PG_EXTENSION
- PG_EXTENSION_DATA_SOURCE
- PG_FOREIGN_DATA_WRAPPER
- PG_FOREIGN_SERVER
- PG_FOREIGN_TABLE
- PG_INDEX
- PG_INHERITS
- PG_JOB
- PG_JOB_PROC
- PG_LANGUAGE
- PG_LARGEOBJECT
- PG_LARGEOBJECT_METADATA
- PG_NAMESPACE
- PG_OBJECT
- PG_OPCLASS
- PG_OPERATOR
- PG_OPFAMILY
- PG_PARTITION
- PG_PLTEMPLATE
- PG_PROC
- PG_RANGE
- PG_RESOURCE_POOL
- PG_REWRITE
- PG_RLSPOLICY
- PG_SECLABEL
- PG_SHDEPEND
- PG_SHDESCRIPTION
- PG_SHSECLABEL
- PG_STATISTIC
- PG_STATISTIC_EXT
- PG_TABLESPACE
- PG_TRIGGER
- PG_TS_CONFIG
- PG_TS_CONFIG_MAP
- PG_TS_DICT
- PG_TS_PARSER
- PG_TS_TEMPLATE
- PG_TYPE
- PG_USER_MAPPING
- PG_USER_STATUS
- PG_WORKLOAD_GROUP
- PLAN_TABLE_DATA
- STATEMENT_HISTORY
- 系统视图
- GS_SESSION_CPU_STATISTICS
- GS_SESSION_MEMORY_STATISTICS
- GS_SQL_COUNT
- GS_WLM_OPERATOR_HISTORY
- GS_WLM_OPERATOR_STATISTICS
- GS_WLM_PLAN_OPERATOR_HISTORY
- GS_WLM_REBUILD_USER_RESOURCE_POOL
- GS_WLM_RESOURCE_POOL
- GS_WLM_SESSION_HISTORY
- GS_WLM_SESSION_INFO_ALL
- GS_WLM_USER_INFO
- GS_WLM_SESSION_STATISTICS
- GS_STAT_SESSION_CU
- MPP_TABLES
- PG_AVAILABLE_EXTENSION_VERSIONS
- PG_AVAILABLE_EXTENSIONS
- PG_CURSORS
- PG_EXT_STATS
- PG_GET_INVALID_BACKENDS
- PG_GET_SENDERS_CATCHUP_TIME
- PG_GROUP
- PG_GTT_RELSTATS
- PG_GTT_STATS
- PG_GTT_ATTACHED_PIDS
- PG_INDEXES
- PG_LOCKS
- PG_MATVIEWS
- PG_NODE_ENV
- PG_OS_THREADS
- PG_PREPARED_STATEMENTS
- PG_PREPARED_XACTS
- PG_REPLICATION_SLOTS
- PG_RLSPOLICIES
- PG_ROLES
- PG_RULES
- PG_SECLABELS
- PG_SESSION_WLMSTAT
- PG_SESSION_IOSTAT
- PG_SETTINGS
- PG_SHADOW
- PG_STATS
- PG_STAT_ACTIVITY
- PG_STAT_ALL_INDEXES
- PG_STAT_ALL_TABLES
- PG_STAT_BAD_BLOCK
- PG_STAT_BGWRITER
- PG_STAT_DATABASE
- PG_STAT_DATABASE_CONFLICTS
- PG_STAT_USER_FUNCTIONS
- PG_STAT_USER_INDEXES
- PG_STAT_USER_TABLES
- PG_STAT_REPLICATION
- PG_STAT_SYS_INDEXES
- PG_STAT_SYS_TABLES
- PG_STAT_XACT_ALL_TABLES
- PG_STAT_XACT_SYS_TABLES
- PG_STAT_XACT_USER_FUNCTIONS
- PG_STAT_XACT_USER_TABLES
- PG_STATIO_ALL_INDEXES
- PG_STATIO_ALL_SEQUENCES
- PG_STATIO_ALL_TABLES
- PG_STATIO_SYS_INDEXES
- PG_STATIO_SYS_SEQUENCES
- PG_STATIO_SYS_TABLES
- PG_STATIO_USER_INDEXES
- PG_STATIO_USER_SEQUENCES
- PG_STATIO_USER_TABLES
- PG_THREAD_WAIT_STATUS
- PG_TABLES
- PG_TDE_INFO
- PG_TIMEZONE_NAMES
- PG_TOTAL_USER_RESOURCE_INFO
- PG_USER
- PG_USER_MAPPINGS
- PG_VIEWS
- PG_WLM_STATISTICS
- PLAN_TABLE
- GS_FILE_STAT
- GS_OS_RUN_INFO
- GS_REDO_STAT
- GS_SESSION_MEMORY
- GS_SESSION_MEMORY_DETAIL
- GS_SESSION_STAT
- GS_SESSION_TIME
- GS_THREAD_MEMORY_DETAIL
- GS_TOTAL_MEMORY_DETAIL
- PG_TIMEZONE_ABBREVS
- PG_TOTAL_USER_RESOURCE_INFO_OID
- PG_VARIABLE_INFO
- GS_INSTANCE_TIME
- 系统函数
- 支持的数据类型
- SQL 语法
- ABORT
- ALTER DATABASE
- ALTER DATA SOURCE
- ALTER DEFAULT PRIVILEGES
- ALTER DIRECTORY
- ALTER FOREIGN TABLE
- ALTER FUNCTION
- ALTER GROUP
- ALTER INDEX
- ALTER LARGE OBJECT
- ALTER MATERIALIZED VIEW
- ALTER ROLE
- ALTER ROW LEVEL SECURITY POLICY
- ALTER RULE
- ALTER SCHEMA
- ALTER SEQUENCE
- ALTER SERVER
- ALTER SESSION
- ALTER SYNONYM
- ALTER SYSTEM KILL SESSION
- ALTER SYSTEM SET
- ALTER TABLE
- ALTER TABLE PARTITION
- ALTER TABLESPACE
- ALTER TEXT SEARCH CONFIGURATION
- ALTER TEXT SEARCH DICTIONARY
- ALTER TRIGGER
- ALTER TYPE
- ALTER USER
- ALTER USER MAPPING
- ALTER VIEW
- ANALYZE | ANALYSE
- BEGIN
- CALL
- CHECKPOINT
- CLOSE
- CLUSTER
- COMMENT
- COMMIT | END
- COMMIT PREPARED
- COPY
- CREATE CLIENT MASTER KEY
- CREATE COLUMN ENCRYPTION KEY
- CREATE DATABASE
- CREATE DATA SOURCE
- CREATE DIRECTORY
- CREATE FOREIGN TABLE
- CREATE FUNCTION
- CREATE GROUP
- CREATE INDEX
- CREATE MATERIALIZED VIEW
- CREATE ROW LEVEL SECURITY POLICY
- CREATE PROCEDURE
- CREATE ROLE
- CREATE RULE
- CREATE SCHEMA
- CREATE SEQUENCE
- CREATE SERVER
- CREATE SYNONYM
- CREATE TABLE
- CREATE TABLE AS
- CREATE TABLE PARTITION
- CREATE TABLESPACE
- CREATE TEXT SEARCH CONFIGURATION
- CREATE TEXT SEARCH DICTIONARY
- CREATE TRIGGER
- CREATE TYPE
- CREATE USER
- CREATE USER MAPPING
- CREATE VIEW
- CURSOR
- DEALLOCATE
- DECLARE
- DELETE
- DO
- DROP CLIENT MASTER KEY
- DROP COLUMN ENCRYPTION KEY
- DROP DATABASE
- DROP DATA SOURCE
- DROP DIRECTORY
- DROP FOREIGN TABLE
- DROP FUNCTION
- DROP GROUP
- DROP INDEX
- DROP MATERIALIZED VIEW
- DROP OWNED
- DROP ROW LEVEL SECURITY POLICY
- DROP PROCEDURE
- DROP ROLE
- DROP RULE
- DROP SCHEMA
- DROP SEQUENCE
- DROP SERVER
- DROP SYNONYM
- DROP TABLE
- DROP TABLESPACE
- DROP TEXT SEARCH CONFIGURATION
- DROP TEXT SEARCH DICTIONARY
- DROP TRIGGER
- DROP TYPE
- DROP USER
- DROP USER MAPPING
- DROP VIEW
- EXECUTE
- EXPLAIN
- EXPLAIN PLAN
- FETCH
- GRANT
- INSERT
- LOCK
- MOVE
- MERGE INTO
- PREPARE
- PREPARE TRANSACTION
- REASSIGN OWNED
- REFRESH MATERIALIZED VIEW
- REINDEX
- RELEASE SAVEPOINT
- RESET
- REVOKE
- ROLLBACK
- ROLLBACK PREPARED
- ROLLBACK TO SAVEPOINT
- SAVEPOINT
- SELECT
- SELECT INTO
- SET
- SET CONSTRAINTS
- SET ROLE
- SET SESSION AUTHORIZATION
- SET TRANSACTION
- SHOW
- SHUTDOW
- START TRANSACTION
- TRUNCATE
- UPDATE
- VACUUM
- VALUES
- GUC参数说明
- DBE_PERF
- 概述
- OS
- Instance
- Memory
- File
- Object
- STAT_USER_TABLES
- SUMMARY_STAT_USER_TABLES
- GLOBAL_STAT_USER_TABLES
- STAT_USER_INDEXES
- SUMMARY_STAT_USER_INDEXES
- GLOBAL_STAT_USER_INDEXES
- STAT_SYS_TABLES
- SUMMARY_STAT_SYS_TABLES
- GLOBAL_STAT_SYS_TABLES
- STAT_SYS_INDEXES
- SUMMARY_STAT_SYS_INDEXES
- GLOBAL_STAT_SYS_INDEXES
- STAT_ALL_TABLES
- SUMMARY_STAT_ALL_TABLES
- GLOBAL_STAT_ALL_TABLES
- STAT_ALL_INDEXES
- SUMMARY_STAT_ALL_INDEXES
- GLOBAL_STAT_ALL_INDEXES
- STAT_DATABASE
- SUMMARY_STAT_DATABASE
- GLOBAL_STAT_DATABASE
- STAT_DATABASE_CONFLICTS
- SUMMARY_STAT_DATABASE_CONFLICTS
- GLOBAL_STAT_DATABASE_CONFLICTS
- STAT_XACT_ALL_TABLES
- SUMMARY_STAT_XACT_ALL_TABLES
- GLOBAL_STAT_XACT_ALL_TABLES
- STAT_XACT_SYS_TABLES
- SUMMARY_STAT_XACT_SYS_TABLES
- GLOBAL_STAT_XACT_SYS_TABLES
- STAT_XACT_USER_TABLES
- SUMMARY_STAT_XACT_USER_TABLES
- GLOBAL_STAT_XACT_USER_TABLES
- STAT_XACT_USER_FUNCTIONS
- SUMMARY_STAT_XACT_USER_FUNCTIONS
- GLOBAL_STAT_XACT_USER_FUNCTIONS
- STAT_BAD_BLOCK
- SUMMARY_STAT_BAD_BLOCK
- GLOBAL_STAT_BAD_BLOCK
- STAT_USER_FUNCTIONS
- SUMMARY_STAT_USER_FUNCTIONS
- GLOBAL_STAT_USER_FUNCTIONS
- Workload
- Session/Thread
- SESSION_STAT
- GLOBAL_SESSION_STAT
- SESSION_TIME
- GLOBAL_SESSION_TIME
- SESSION_MEMORY
- GLOBAL_SESSION_MEMORY
- SESSION_MEMORY_DETAIL
- GLOBAL_SESSION_MEMORY_DETAIL
- SESSION_STAT_ACTIVITY
- GLOBAL_SESSION_STAT_ACTIVITY
- THREAD_WAIT_STATUS
- GLOBAL_THREAD_WAIT_STATUS
- LOCAL_THREADPOOL_STATUS
- GLOBAL_THREADPOOL_STATUS
- SESSION_CPU_RUNTIME
- SESSION_MEMORY_RUNTIME
- STATEMENT_IOSTAT_COMPLEX_RUNTIME
- Transaction
- Query
- STATEMENT
- SUMMARY_STATEMENT
- STATEMENT_COUNT
- GLOBAL_STATEMENT_COUNT
- SUMMARY_STATEMENT_COUNT
- GLOBAL_STATEMENT_COMPLEX_HISTORY
- GLOBAL_STATEMENT_COMPLEX_HISTORY_TABLE
- GLOBAL_STATEMENT_COMPLEX_RUNTIME
- STATEMENT_RESPONSETIME_PERCENTILE
- STATEMENT_USER_COMPLEX_HISTORY
- STATEMENT_COMPLEX_RUNTIME
- STATEMENT_COMPLEX_HISTORY_TABLE
- STATEMENT_COMPLEX_HISTORY
- STATEMENT_WLMSTAT_COMPLEX_RUNTIME
- STATEMENT_HISTORY
- Cache/IO
- STATIO_USER_TABLES
- SUMMARY_STATIO_USER_TABLES
- GLOBAL_STATIO_USER_TABLES
- STATIO_USER_INDEXES
- SUMMARY_STATIO_USER_INDEXES
- GLOBAL_STATIO_USER_INDEXES
- STATIO_USER_SEQUENCES
- SUMMARY_STATIO_USER_SEQUENCES
- GLOBAL_STATIO_USER_SEQUENCES
- STATIO_SYS_TABLES
- SUMMARY_STATIO_SYS_TABLES
- GLOBAL_STATIO_SYS_TABLES
- STATIO_SYS_INDEXES
- SUMMARY_STATIO_SYS_INDEXES
- GLOBAL_STATIO_SYS_INDEXES
- STATIO_SYS_SEQUENCES
- SUMMARY_STATIO_SYS_SEQUENCES
- GLOBAL_STATIO_SYS_SEQUENCES
- STATIO_ALL_TABLES
- SUMMARY_STATIO_ALL_TABLES
- GLOBAL_STATIO_ALL_TABLES
- STATIO_ALL_INDEXES
- SUMMARY_STATIO_ALL_INDEXES
- GLOBAL_STATIO_ALL_INDEXES
- STATIO_ALL_SEQUENCES
- SUMMARY_STATIO_ALL_SEQUENCES
- GLOBAL_STATIO_ALL_SEQUENCES
- GLOBAL_STAT_DB_CU
- GLOBAL_STAT_SESSION_CU
- Utility
- REPLICATION_STAT
- GLOBAL_REPLICATION_STAT
- REPLICATION_SLOTS
- GLOBAL_REPLICATION_SLOTS
- BGWRITER_STAT
- GLOBAL_BGWRITER_STAT
- GLOBAL_CKPT_STATUS
- GLOBAL_DOUBLE_WRITE_STATUS
- GLOBAL_PAGEWRITER_STATUS
- GLOBAL_RECORD_RESET_TIME
- GLOBAL_REDO_STATUS
- GLOBAL_RECOVERY_STATUS
- CLASS_VITAL_INFO
- USER_LOGIN
- SUMMARY_USER_LOGIN
- GLOBAL_GET_BGWRITER_STATUS
- Lock
- Wait Events
- Configuration
- Operator
- Workload Manager
- Global Plancache
- 附录
- 数据库报错信息
- SQL标准错误码说明
- 第三方库错误码说明
- GAUSS-00001 - GAUSS-00100
- GAUSS-00101 - GAUSS-00200
- GAUSS 00201 - GAUSS 00300
- GAUSS 00301 - GAUSS 00400
- GAUSS 00401 - GAUSS 00500
- GAUSS 00501 - GAUSS 00600
- GAUSS 00601 - GAUSS 00700
- GAUSS 00701 - GAUSS 00800
- GAUSS 00801 - GAUSS 00900
- GAUSS 00901 - GAUSS 01000
- GAUSS 01001 - GAUSS 01100
- GAUSS 01101 - GAUSS 01200
- GAUSS 01201 - GAUSS 01300
- GAUSS 01301 - GAUSS 01400
- GAUSS 01401 - GAUSS 01500
- GAUSS 01501 - GAUSS 01600
- GAUSS 01601 - GAUSS 01700
- GAUSS 01701 - GAUSS 01800
- GAUSS 01801 - GAUSS 01900
- GAUSS 01901 - GAUSS 02000
- GAUSS 02001 - GAUSS 02100
- GAUSS 02101 - GAUSS 02200
- GAUSS 02201 - GAUSS 02300
- GAUSS 02301 - GAUSS 02400
- GAUSS 02401 - GAUSS 02500
- GAUSS 02501 - GAUSS 02600
- GAUSS 02601 - GAUSS 02700
- GAUSS 02701 - GAUSS 02800
- GAUSS 02801 - GAUSS 02900
- GAUSS 02901 - GAUSS 03000
- GAUSS 03001 - GAUSS 03100
- GAUSS 03101 - GAUSS 03200
- GAUSS 03201 - GAUSS 03300
- GAUSS 03301 - GAUSS 03400
- GAUSS 03401 - GAUSS 03500
- GAUSS 03501 - GAUSS 03600
- GAUSS 03601 - GAUSS 03700
- GAUSS 03701 - GAUSS 03800
- GAUSS 03801 - GAUSS 03900
- GAUSS 03901 - GAUSS 04000
- GAUSS 04001 - GAUSS 04100
- GAUSS 04101 - GAUSS 04200
- GAUSS 04201 - GAUSS 04300
- GAUSS 04301 - GAUSS 04400
- GAUSS 04401 - GAUSS 04500
- GAUSS 04501 - GAUSS 04600
- GAUSS 04601 - GAUSS 04700
- GAUSS 04701 - GAUSS 04800
- GAUSS 04801 - GAUSS 04900
- GAUSS 04901 - GAUSS 05000
- GAUSS 05001 - GAUSS 05100
- GAUSS 05101 - GAUSS 05200
- GAUSS 05201 - GAUSS 05300
- GAUSS 05301 - GAUSS 05400
- GAUSS 05401 - GAUSS 05500
- GAUSS 05501 - GAUSS 05600
- GAUSS 05601 - GAUSS 05700
- GAUSS 05701 - GAUSS 05800
- GAUSS 05801 - GAUSS 05900
- GAUSS 05901 - GAUSS 06000
- GAUSS 06001 - GAUSS 06100
- GAUSS 06101 - GAUSS 06200
- GAUSS 06201 - GAUSS 06300
- GAUSS 06301 - GAUSS 06400
- GAUSS 06401 - GAUSS 06500
- GAUSS 06501 - GAUSS 06600
- GAUSS 06601 - GAUSS 06700
- GAUSS 06701 - GAUSS 06800
- GAUSS 06801 - GAUSS 06900
- GAUSS 06901 - GAUSS 07000
- GAUSS 07001 - GAUSS 07100
- GAUSS 07101 - GAUSS 07200
- GAUSS 07201 - GAUSS 07300
- GAUSS 07301 - GAUSS 07400
- GAUSS 07401 - GAUSS 07480
- GAUSS 50000 - GAUSS 50999
- GAUSS 51000 - GAUSS 51999
- GAUSS 52000 - GAUSS 52999
- GAUSS 53000 - GAUSS 53699
- 系统表及系统视图
- 术语表
参考文献
[1] Y. Mao, E. Kohler, and R. T. Morris. Cache craftiness for fast multicore key-value storage. In Proc. 7th ACM European Conference on Computer Systems (EuroSys), Apr. 2012.
[2] K. Ren, T. Diamond, D. J. Abadi, and A. Thomson. Low-overhead asynchronous checkpointing in main-memory database systems. In Proceedings of the 2016 ACM SIGMOD International Conference on Management of Data, 2016.
[5] Tu, S., Zheng, W., Kohler, E., Liskov, B., and Madden, S. Speedy transactions in multicore in-memory databases. In Proceedings of the Twenty-Fourth ACM Symposium on Operating Systems Principles (New York, NY, USA, 2013), SOSP ’13, ACM, pp. 18-32.
[6] H. Avni at al. Industrial-Strength OLTP Using Main Memory and Many-cores, VLDB 2020.
[7] Bernstein, P. A., and Goodman, N. Concurrency control in distributed database systems. ACM Comput. Surv. 13, 2 (1981), 185-221.
[8] Felber, P., Fetzer, C., and Riegel, T. Dynamic performance tuning of word-based software transactional memory. In Proceedings of the 13th ACM SIGPLAN Symposium on Principles and Practice of Parallel Programming, PPOPP 2008, Salt Lake City, UT, USA, February 20-23, 2008 (2008),
pp. 237-246.
[9] Appuswamy, R., Anadiotis, A., Porobic, D., Iman, M., and Ailamaki, A. Analyzing the impact of system architecture on the scalability of OLTP engines for high-contention workloads. PVLDB 11, 2 (2017),
121-134.
[10] R. Sherkat, C. Florendo, M. Andrei, R. Blanco, A. Dragusanu, A. Pathak, P. Khadilkar, N. Kulkarni, C. Lemke, S. Seifert, S. Iyer, S. Gottapu, R. Schulze, C. Gottipati, N. Basak, Y. Wang, V. Kandiyanallur, S. Pendap, D. Gala, R. Almeida, and P. Ghosh. Native store extension for SAP HANA. PVLDB, 12(12):
2047-2058, 2019.
[11] X. Yu, A. Pavlo, D. Sanchez, and S. Devadas. Tictoc: Time traveling optimistic concurrency control. In Proceedings of the 2016 International Conference on Management of Data, SIGMOD Conference 2016, San Francisco, CA, USA, June 26 - July 01, 2016, pages 1629-1642, 2016.
[12] V. Leis, A. Kemper, and T. Neumann. The adaptive radix tree: Artful indexing for main-memory databases. In C. S. Jensen, C. M. Jermaine, and X. Zhou, editors, 29th IEEE International Conference on Data Engineering, ICDE 2013, Brisbane, Australia, April 8-12, 2013, pages 38-49. IEEE Computer Society, 2013.
[13] S. K. Cha, S. Hwang, K. Kim, and K. Kwon. Cache-conscious concurrency control of main-memory indexes on shared-memory multiprocessor systems. In P. M. G. Apers, P. Atzeni, S. Ceri, S. Paraboschi, K. Ramamohanarao, and R. T. Snodgrass, editors, VLDB 2001, Proceedings of 27th International Conference on Very Large Data Bases, September 11-14, 2001, Roma, Italy, pages 181-190. Morga Kaufmann, 2001.