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前言 何为PostgreSQL? PostgreSQL简史 格式约定 更多信息 臭虫汇报指导 I. 教程 章1. 从头开始 1.1. 安装 1.2. 体系基本概念 1.3. 创建一个数据库 1.4. 访问数据库 章2. SQL语言 2.1. 介绍 2.2. 概念 2.3. 创建新表 2.4. 向表中添加行 2.5. 查询一个表 2.6. 表间链接 2.7. 聚集函数 2.8. 更新 2.9. 删除 章3. 高级特性 3.1. 介绍 3.2. 视图 3.3. 外键 3.4. 事务 3.5. 窗口函数 3.6. 继承 3.7. 结论 II. SQL语言 章4. SQL语法 4.1. 词法结构 4.2. 值表达式 4.3. 调用函数 章5. 数据定义 5.1. 表的基本概念 5.2. 缺省值 5.3. 约束 5.4. 系统字段 5.5. 修改表 5.6. 权限 5.7. 模式 5.8. 继承 5.9. 分区 5.10. 其它数据库对象 5.11. 依赖性跟踪 章 6. 数据操作 6.1. 插入数据 6.2. 更新数据 6.3. 删除数据 章7. 查询 7.1. 概述 7.2. 表表达式 7.3. 选择列表 7.4. 组合查询 7.5. 行排序 7.6. LIMIT和OFFSET 7.7. VALUES列表 7.8. WITH的查询(公用表表达式) 章8. 数据类型 8.1. 数值类型 8.2. 货币类型 8.3. 字符类型 8.4. 二进制数据类型 8.5. 日期/时间类型 8.6. 布尔类型 8.7. 枚举类型 8.8. 几何类型 8.9. 网络地址类型 8.10. 位串类型 8.11. 文本搜索类型 8.12. UUID类型 8.13. XML类型 8.14. 数组 8.15. 复合类型 8.16. 对象标识符类型 8.17. 伪类型 章 9. 函数和操作符 9.1. 逻辑操作符 9.2. 比较操作符 9.3. 数学函数和操作符 9.4. 字符串函数和操作符 9.5. 二进制字符串函数和操作符 9.6. 位串函数和操作符 9.7. 模式匹配 9.8. 数据类型格式化函数 9.9. 时间/日期函数和操作符 9.10. 支持枚举函数 9.11. 几何函数和操作符 9.12. 网络地址函数和操作符 9.13. 文本检索函数和操作符 9.14. XML函数 9.15. 序列操作函数 9.16. 条件表达式 9.17. 数组函数和操作符 9.18. 聚合函数 9.19. 窗口函数 9.20. 子查询表达式 9.21. 行和数组比较 9.22. 返回集合的函数 9.23. 系统信息函数 9.24. 系统管理函数 9.25. 触发器函数 章10. 类型转换 10.3. 函数 10.2. 操作符 10.1. 概述 10.4. 值存储 10.5. UNION 章11. 索引 11.1. 介绍 11.2. 索引类型 11.3. 多字段索引 11.4. 索引和ORDER BY 11.5. 组合多个索引 11.6. 唯一索引 11.7. 表达式上的索引 11.8. 部分索引 11.9. 操作类和操作簇 11.10. 检查索引的使用 章12. Full Text Search 12.1. Introduction 12.2. Tables and Indexes 12.3. Controlling Text Search 12.4. Additional Features 12.5. Parsers 12.6. Dictionaries 12.7. Configuration Example 12.8. Testing and Debugging Text Search 12.9. GiST and GIN Index Types 12.10. psql Support 12.11. Limitations 12.12. Migration from Pre-8.3 Text Search 章13. 并发控制 13.1. 介绍 13.2. 事务隔离 13.3. 明确锁定 13.4. 应用层数据完整性检查 13.5. 锁和索引 章14. 性能提升技巧 14.1. 使用EXPLAIN 14.2. 规划器使用的统计信息 14.3. 用明确的JOIN语句控制规划器 14.4. 向数据库中添加记录 14.5. 非持久性设置 III. 服务器管理 章15. 安装指导 15.1. 简版 15.2. 要求 15.3. 获取源码 15.4. 升级 15.5. 安装过程 15.6. 安装后的设置 15.7. 支持的平台 15.8. 特殊平台的要求 章16. Installation from Source Code on Windows 16.1. Building with Visual C++ or the Platform SDK 16.2. Building libpq with Visual C++ or Borland C++ 章17. 服务器安装和操作 17.1. PostgreSQL用户帐户 17.2. 创建数据库集群 17.3. 启动数据库服务器 17.4. 管理内核资源 17.5. 关闭服务 17.6. 防止服务器欺骗 17.7. 加密选项 17.8. 用SSL进行安全的TCP/IP连接 17.9. Secure TCP/IP Connections with SSH Tunnels 章18. 服务器配置 18.1. 设置参数 18.2. 文件位置 18.3. 连接和认证 18.4. 资源消耗 18.5. 预写式日志 18.6. 查询规划 18.7. 错误报告和日志 18.8. 运行时统计 18.9. 自动清理 18.10. 客户端连接缺省 18.12. 版本和平台兼容性 18.11. 锁管理 18.13. 预置选项 18.14. 自定义的选项 18.15. 开发人员选项 18.16. 短选项 章19. 用户认证 19.1. pg_hba.conf 文件 19.2. 用户名映射 19.3. 认证方法 19.4. 用户认证 章20. 数据库角色和权限 20.1. 数据库角色 20.2. 角色属性 20.3. 权限 20.4. 角色成员 20.5. 函数和触发器 章21. 管理数据库 21.1. 概述 21.2. 创建一个数据库 21.3. 临时库 21.4. 数据库配置 21.5. 删除数据库 21.6. 表空间 章22. 本土化 22.1. 区域支持 22.2. 字符集支持 章23. 日常数据库维护工作 23.1. Routine Vacuuming日常清理 23.2. 经常重建索引 23.3. 日志文件维护 章24. 备份和恢复 24.1. SQL转储 24.2. 文件系统级别的备份 24.3. 在线备份以及即时恢复(PITR) 24.4. 版本间迁移 章25. 高可用性与负载均衡,复制 25.1. 不同解决方案的比较 25.2. 日志传送备份服务器 25.3. 失效切换 25.4. 日志传送的替代方法 25.5. 热备 章26. 恢复配置 26.1. 归档恢复设置 26.2. 恢复目标设置 26.3. 备服务器设置 章27. 监控数据库的活动 27.1. 标准Unix工具 27.2. 统计收集器 27.3. 查看锁 27.4. 动态跟踪 章28. 监控磁盘使用情况 28.1. 判断磁盘的使用量 28.2. 磁盘满导致的失效 章29. 可靠性和预写式日志 29.1. 可靠性 29.2. 预写式日志(WAL) 29.3. 异步提交 29.4. WAL配置 29.5. WAL内部 章30. Regression Tests 30.1. Running the Tests 30.2. Test Evaluation 30.3. Variant Comparison Files 30.4. Test Coverage Examination IV. 客户端接口 章31. libpq-C库 31.1. 数据库联接函数 31.2. 连接状态函数 31.3. 命令执行函数 31.4. 异步命令处理 31.5. 取消正在处理的查询 31.6. 捷径接口 31.7. 异步通知 31.8. 与COPY命令相关的函数 31.9. Control Functions 控制函数 31.10. 其他函数 31.11. 注意信息处理 31.12. 事件系统 31.13. 环境变量 31.14. 口令文件 31.15. 连接服务的文件 31.16. LDAP查找连接参数 31.17. SSL支持 31.18. 在多线程程序里的行为 31.19. 制作libpq程序 31.20. 例子程序 章32. 大对象 32.1. 介绍 32.2. 实现特点 32.3. 客户端接口 32.4. 服务器端函数 32.5. 例子程序 章33. ECPG - Embedded SQL in C 33.1. The Concept 33.2. Connecting to the Database Server 33.3. Closing a Connection 33.4. Running SQL Commands 33.5. Choosing a Connection 33.6. Using Host Variables 33.7. Dynamic SQL 33.8. pgtypes library 33.9. Using Descriptor Areas 33.10. Informix compatibility mode 33.11. Error Handling 33.12. Preprocessor directives 33.13. Processing Embedded SQL Programs 33.14. Library Functions 33.15. Internals 章34. 信息模式 34.1. 关于这个模式 34.2. 数据类型 34.3. information_schema_catalog_name 34.4. administrable_role_authorizations 34.5. applicable_roles 34.6. attributes 34.7. check_constraint_routine_usage 34.8. check_constraints 34.9. column_domain_usage 34.10. column_privileges 34.11. column_udt_usage 34.12. 字段 34.13. constraint_column_usage 34.14. constraint_table_usage 34.15. data_type_privileges 34.16. domain_constraints 34.18. domains 34.17. domain_udt_usage 34.19. element_types 34.20. enabled_roles 34.21. foreign_data_wrapper_options 34.22. foreign_data_wrappers 34.23. foreign_server_options 34.24. foreign_servers 34.25. key_column_usage 34.26. parameters 34.27. referential_constraints 34.28. role_column_grants 34.29. role_routine_grants 34.30. role_table_grants 34.31. role_usage_grants 34.32. routine_privileges 34.33. routines 34.34. schemata 34.35. sequences 34.36. sql_features 34.37. sql_implementation_info 34.38. sql_languages 34.39. sql_packages 34.40. sql_parts 34.41. sql_sizing 34.42. sql_sizing_profiles 34.43. table_constraints 34.44. table_privileges 34.45. tables 34.46. triggered_update_columns 34.47. 触发器 34.48. usage_privileges 34.49. user_mapping_options 34.50. user_mappings 34.51. view_column_usage 34.52. view_routine_usage 34.53. view_table_usage 34.54. 视图 V. 服务器端编程 章35. 扩展SQL 35.1. 扩展性是如何实现的 35.2. PostgreSQL类型系统 35.3. User-Defined Functions 35.4. Query Language (SQL) Functions 35.5. Function Overloading 35.6. Function Volatility Categories 35.7. Procedural Language Functions 35.8. Internal Functions 35.9. C-Language Functions 35.10. User-Defined Aggregates 35.11. User-Defined Types 35.12. User-Defined Operators 35.13. Operator Optimization Information 35.14. Interfacing Extensions To Indexes 35.15. 用C++扩展 章36. 触发器 36.1. 触发器行为概述 36.3. 用 C 写触发器 36.2. 数据改变的可视性 36.4. 一个完整的例子 章37. 规则系统 37.1. The Query Tree 37.2. 视图和规则系统 37.3. 在INSERT,UPDATE和DELETE上的规则 37.4. 规则和权限 37.5. 规则和命令状态 37.6. 规则与触发器得比较 章38. Procedural Languages 38.1. Installing Procedural Languages 章39. PL/pgSQL - SQL过程语言 39.1. 概述 39.2. PL/pgSQL的结构 39.3. 声明 39.4. 表达式 39.5. 基本语句 39.6. 控制结构 39.7. 游标 39.8. 错误和消息 39.9. 触发器过程 39.10. PL/pgSQL Under the Hood 39.11. 开发PL/pgSQL的一些提示 39.12. 从OraclePL/SQL 进行移植 章40. PL/Tcl - Tcl Procedural Language 40.1. Overview 40.2. PL/Tcl Functions and Arguments 40.3. Data Values in PL/Tcl 40.4. Global Data in PL/Tcl 40.5. Database Access from PL/Tcl 40.6. Trigger Procedures in PL/Tcl 40.7. Modules and the unknown command 40.8. Tcl Procedure Names 章41. PL/Perl - Perl Procedural Language 41.1. PL/Perl Functions and Arguments 41.2. Data Values in PL/Perl 41.3. Built-in Functions 41.4. Global Values in PL/Perl 41.6. PL/Perl Triggers 41.5. Trusted and Untrusted PL/Perl 41.7. PL/Perl Under the Hood 章42. PL/Python - Python Procedural Language 42.1. Python 2 vs. Python 3 42.2. PL/Python Functions 42.3. Data Values 42.4. Sharing Data 42.5. Anonymous Code Blocks 42.6. Trigger Functions 42.7. Database Access 42.8. Utility Functions 42.9. Environment Variables 章43. Server Programming Interface 43.1. Interface Functions Spi-spi-connect Spi-spi-finish Spi-spi-push Spi-spi-pop Spi-spi-execute Spi-spi-exec Spi-spi-execute-with-args Spi-spi-prepare Spi-spi-prepare-cursor Spi-spi-prepare-params Spi-spi-getargcount Spi-spi-getargtypeid Spi-spi-is-cursor-plan Spi-spi-execute-plan Spi-spi-execute-plan-with-paramlist Spi-spi-execp Spi-spi-cursor-open Spi-spi-cursor-open-with-args Spi-spi-cursor-open-with-paramlist Spi-spi-cursor-find Spi-spi-cursor-fetch Spi-spi-cursor-move Spi-spi-scroll-cursor-fetch Spi-spi-scroll-cursor-move Spi-spi-cursor-close Spi-spi-saveplan 43.2. Interface Support Functions Spi-spi-fname Spi-spi-fnumber Spi-spi-getvalue Spi-spi-getbinval Spi-spi-gettype Spi-spi-gettypeid Spi-spi-getrelname Spi-spi-getnspname 43.3. Memory Management Spi-spi-palloc Spi-realloc Spi-spi-pfree Spi-spi-copytuple Spi-spi-returntuple Spi-spi-modifytuple Spi-spi-freetuple Spi-spi-freetupletable Spi-spi-freeplan 43.4. Visibility of Data Changes 43.5. Examples VI. 参考手册 I. SQL命令 Sql-abort Sql-alteraggregate Sql-alterconversion Sql-alterdatabase Sql-alterdefaultprivileges Sql-alterdomain Sql-alterforeigndatawrapper Sql-alterfunction Sql-altergroup Sql-alterindex Sql-alterlanguage Sql-alterlargeobject Sql-alteroperator Sql-alteropclass Sql-alteropfamily Sql-alterrole Sql-alterschema Sql-altersequence Sql-alterserver Sql-altertable Sql-altertablespace Sql-altertsconfig Sql-altertsdictionary Sql-altertsparser Sql-altertstemplate Sql-altertrigger Sql-altertype Sql-alteruser Sql-alterusermapping Sql-alterview Sql-analyze Sql-begin Sql-checkpoint Sql-close Sql-cluster Sql-comment Sql-commit Sql-commit-prepared Sql-copy Sql-createaggregate Sql-createcast Sql-createconstraint Sql-createconversion Sql-createdatabase Sql-createdomain Sql-createforeigndatawrapper Sql-createfunction Sql-creategroup Sql-createindex Sql-createlanguage Sql-createoperator Sql-createopclass Sql-createopfamily Sql-createrole Sql-createrule Sql-createschema Sql-createsequence Sql-createserver Sql-createtable Sql-createtableas Sql-createtablespace Sql-createtsconfig Sql-createtsdictionary Sql-createtsparser Sql-createtstemplate Sql-createtrigger Sql-createtype Sql-createuser Sql-createusermapping Sql-createview Sql-deallocate Sql-declare Sql-delete Sql-discard Sql-do Sql-dropaggregate Sql-dropcast Sql-dropconversion Sql-dropdatabase Sql-dropdomain Sql-dropforeigndatawrapper Sql-dropfunction Sql-dropgroup Sql-dropindex Sql-droplanguage Sql-dropoperator Sql-dropopclass Sql-dropopfamily Sql-drop-owned Sql-droprole Sql-droprule Sql-dropschema Sql-dropsequence Sql-dropserver Sql-droptable Sql-droptablespace Sql-droptsconfig Sql-droptsdictionary Sql-droptsparser Sql-droptstemplate Sql-droptrigger Sql-droptype Sql-dropuser Sql-dropusermapping Sql-dropview Sql-end Sql-execute Sql-explain Sql-fetch Sql-grant Sql-insert Sql-listen Sql-load Sql-lock Sql-move Sql-notify Sql-prepare Sql-prepare-transaction Sql-reassign-owned Sql-reindex Sql-release-savepoint Sql-reset Sql-revoke Sql-rollback Sql-rollback-prepared Sql-rollback-to Sql-savepoint Sql-select Sql-selectinto Sql-set Sql-set-constraints Sql-set-role Sql-set-session-authorization Sql-set-transaction Sql-show Sql-start-transaction Sql-truncate Sql-unlisten Sql-update Sql-vacuum Sql-values II. 客户端应用程序 App-clusterdb App-createdb App-createlang App-createuser App-dropdb App-droplang App-dropuser App-ecpg App-pgconfig App-pgdump App-pg-dumpall App-pgrestore App-psql App-reindexdb App-vacuumdb III. PostgreSQL服务器应用程序 App-initdb App-pgcontroldata App-pg-ctl App-pgresetxlog App-postgres App-postmaster VII. 内部 章44. PostgreSQL内部概览 44.1. 查询路径 44.2. 连接是如何建立起来的 44.3. 分析器阶段 44.4. ThePostgreSQL规则系统 44.5. 规划器/优化器 44.6. 执行器 章45. 系统表 45.1. 概述 45.2. pg_aggregate 45.3. pg_am 45.4. pg_amop 45.5. pg_amproc 45.6. pg_attrdef 45.7. pg_attribute 45.8. pg_authid 45.9. pg_auth_members 45.10. pg_cast 45.11. pg_class 45.12. pg_constraint 45.13. pg_conversion 45.14. pg_database 45.15. pg_db_role_setting 45.16. pg_default_acl 45.17. pg_depend 45.18. pg_description 45.19. pg_enum 45.20. pg_foreign_data_wrapper 45.21. pg_foreign_server 45.22. pg_index 45.23. pg_inherits 45.24. pg_language 45.25. pg_largeobject 45.26. pg_largeobject_metadata 45.27. pg_namespace 45.28. pg_opclass 45.29. pg_operator 45.30. pg_opfamily 45.31. pg_pltemplate 45.32. pg_proc 45.33. pg_rewrite 45.34. pg_shdepend 45.35. pg_shdescription 45.36. pg_statistic 45.37. pg_tablespace 45.38. pg_trigger 45.39. pg_ts_config 45.40. pg_ts_config_map 45.41. pg_ts_dict 45.42. pg_ts_parser 45.43. pg_ts_template 45.44. pg_type 45.45. pg_user_mapping 45.46. System Views 45.47. pg_cursors 45.48. pg_group 45.49. pg_indexes 45.50. pg_locks 45.51. pg_prepared_statements 45.52. pg_prepared_xacts 45.53. pg_roles 45.54. pg_rules 45.55. pg_settings 45.56. pg_shadow 45.57. pg_stats 45.58. pg_tables 45.59. pg_timezone_abbrevs 45.60. pg_timezone_names 45.61. pg_user 45.62. pg_user_mappings 45.63. pg_views 章46. Frontend/Backend Protocol 46.1. Overview 46.2. Message Flow 46.3. Streaming Replication Protocol 46.4. Message Data Types 46.5. Message Formats 46.6. Error and Notice Message Fields 46.7. Summary of Changes since Protocol 2.0 47. PostgreSQL Coding Conventions 47.1. Formatting 47.2. Reporting Errors Within the Server 47.3. Error Message Style Guide 章48. Native Language Support 48.1. For the Translator 48.2. For the Programmer 章49. Writing A Procedural Language Handler 章50. Genetic Query Optimizer 50.1. Query Handling as a Complex Optimization Problem 50.2. Genetic Algorithms 50.3. Genetic Query Optimization (GEQO) in PostgreSQL 50.4. Further Reading 章51. 索引访问方法接口定义 51.1. 索引的系统表记录 51.2. 索引访问方法函数 51.3. 索引扫描 51.4. 索引锁的考量 51.5. 索引唯一性检查 51.6. 索引开销估计函数 章52. GiST Indexes 52.1. Introduction 52.2. Extensibility 52.3. Implementation 52.4. Examples 52.5. Crash Recovery 章53. GIN Indexes 53.1. Introduction 53.2. Extensibility 53.3. Implementation 53.4. GIN tips and tricks 53.5. Limitations 53.6. Examples 章54. 数据库物理存储 54.1. 数据库文件布局 54.2. TOAST 54.3. 自由空间映射 54.4. 可见映射 54.5. 数据库分页文件 章55. BKI后端接口 55.1. BKI 文件格式 55.2. BKI命令 55.3. 系统初始化的BKI文件的结构 55.4. 例子 章56. 规划器如何使用统计信息 56.1. 行预期的例子 VIII. 附录 A. PostgreSQL错误代码 B. 日期/时间支持 B.1. 日期/时间输入解析 B.2. 日期/时间关键字 B.3. 日期/时间配置文件 B.4. 日期单位的历史 C. SQL关键字 D. SQL Conformance D.1. Supported Features D.2. Unsupported Features E. 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The Source Code Repository H.1. Getting The Source Via Git I. 文档 I.1. DocBook I.2. 工具集 I.3. 制作文档 I.4. 文档写作 I.5. 风格指导 J. 首字母缩略词 参考书目 Bookindex Index
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E.30. Release 8.3

Release Date: 2008-02-04

E.30.1. Overview

With significant new functionality and performance enhancements, this release represents a major leap forward for PostgreSQL. This was made possible by a growing community that has dramatically accelerated the pace of development. This release adds the following major features:

  • Full text search is integrated into the core database system

  • Support for the SQL/XML standard, including new operators and an XML data type

  • Enumerated data types (ENUM)

  • Arrays of composite types

  • Universally Unique Identifier (UUID) data type

  • Add control over whether NULLs sort first or last

  • Updatable cursors

  • Server configuration parameters can now be set on a per-function basis

  • User-defined types can now have type modifiers

  • Automatically re-plan cached queries when table definitions change or statistics are updated

  • Numerous improvements in logging and statistics collection

  • Support Security Service Provider Interface (SSPI) for authentication on Windows

  • Support multiple concurrent autovacuum processes, and other autovacuum improvements

  • Allow the whole PostgreSQL distribution to be compiled with Microsoft Visual C++

Major performance improvements are listed below. Most of these enhancements are automatic and do not require user changes or tuning:

  • Asynchronous commit delays writes to WAL during transaction commit

  • Checkpoint writes can be spread over a longer time period to smooth the I/O spike during each checkpoint

  • Heap-Only Tuples (HOT) accelerate space reuse for most UPDATEs and DELETEs

  • Just-in-time background writer strategy improves disk write efficiency

  • Using non-persistent transaction IDs for read-only transactions reduces overhead and VACUUM requirements

  • Per-field and per-row storage overhead has been reduced

  • Large sequential scans no longer force out frequently used cached pages

  • Concurrent large sequential scans can now share disk reads

  • ORDER BY ... LIMIT can be done without sorting

The above items are explained in more detail in the sections below.

E.30.2. Migration to Version 8.3

A dump/restore using pg_dump is required for those wishing to migrate data from any previous release.

Observe the following incompatibilities:

E.30.2.1. General

  • Non-character data types are no longer automatically cast to TEXT (Peter, Tom)

    Previously, if a non-character value was supplied to an operator or function that requires text input, it was automatically cast to text, for most (though not all) built-in data types. This no longer happens: an explicit cast to text is now required for all non-character-string types. For example, these expressions formerly worked:

    substr(current_date, 1, 4)
    23 LIKE '2%'

    but will now draw "function does not exist" and "operator does not exist" errors respectively. Use an explicit cast instead:

    substr(current_date::text, 1, 4)
    23::text LIKE '2%'

    (Of course, you can use the more verbose CAST() syntax too.) The reason for the change is that these automatic casts too often caused surprising behavior. An example is that in previous releases, this expression was accepted but did not do what was expected:

    current_date < 2017-11-17

    This is actually comparing a date to an integer, which should be (and now is) rejected — but in the presence of automatic casts both sides were cast to text and a textual comparison was done, because the text < text operator was able to match the expression when no other < operator could.

    Types char(n) and varchar(n) still cast to text automatically. Also, automatic casting to text still works for inputs to the concatenation (||) operator, so long as least one input is a character-string type.

  • Full text search features from contrib/tsearch2 have been moved into the core server, with some minor syntax changes

    contrib/tsearch2 now contains a compatibility interface.

  • ARRAY(SELECT ...), where the SELECT returns no rows, now returns an empty array, rather than NULL (Tom)

  • The array type name for a base data type is no longer always the base type's name with an underscore prefix

    The old naming convention is still honored when possible, but application code should no longer depend on it. Instead use the new pg_type.typarray column to identify the array data type associated with a given type.

  • ORDER BY ... USING operator must now use a less-than or greater-than operator that is defined in a btree operator class

    This restriction was added to prevent inconsistent results.

  • SET LOCAL changes now persist until the end of the outermost transaction, unless rolled back (Tom)

    Previously SET LOCAL's effects were lost after subtransaction commit (RELEASE SAVEPOINT or exit from a PL/pgSQL exception block).

  • Commands rejected in transaction blocks are now also rejected in multiple-statement query strings (Tom)

    For example, "BEGIN; DROP DATABASE; COMMIT" will now be rejected even if submitted as a single query message.

  • ROLLBACK outside a transaction block now issues NOTICE instead of WARNING (Bruce)

  • Prevent NOTIFY/LISTEN/UNLISTEN from accepting schema-qualified names (Bruce)

    Formerly, these commands accepted schema.relation but ignored the schema part, which was confusing.

  • ALTER SEQUENCE no longer affects the sequence's currval() state (Tom)

  • Foreign keys now must match indexable conditions for cross-data-type references (Tom)

    This improves semantic consistency and helps avoid performance problems.

  • Restrict object size functions to users who have reasonable permissions to view such information (Tom)

    For example, pg_database_size() now requires CONNECT permission, which is granted to everyone by default. pg_tablespace_size() requires CREATE permission in the tablespace, or is allowed if the tablespace is the default tablespace for the database.

  • Remove the undocumented !!= (not in) operator (Tom)

    NOT IN (SELECT ...) is the proper way to perform this operation.

  • Internal hashing functions are now more uniformly-distributed (Tom)

    If application code was computing and storing hash values using internal PostgreSQL hashing functions, the hash values must be regenerated.

  • C-code conventions for handling variable-length data values have changed (Greg Stark, Tom)

    The new SET_VARSIZE() macro must be used to set the length of generated varlena values. Also, it might be necessary to expand ("de-TOAST") input values in more cases.

  • Continuous archiving no longer reports each successful archive operation to the server logs unless DEBUG level is used (Simon)

E.30.2.2. Configuration Parameters

  • Numerous changes in administrative server parameters

    bgwriter_lru_percent, bgwriter_all_percent, bgwriter_all_maxpages, stats_start_collector, and stats_reset_on_server_start are removed. redirect_stderr is renamed to logging_collector. stats_command_string is renamed to track_activities. stats_block_level and stats_row_level are merged into track_counts. A new boolean configuration parameter, archive_mode, controls archiving. Autovacuum's default settings have changed.

  • Remove stats_start_collector parameter (Tom)

    We now always start the collector process, unless UDP socket creation fails.

  • Remove stats_reset_on_server_start parameter (Tom)

    This was removed because pg_stat_reset() can be used for this purpose.

  • Commenting out a parameter in postgresql.conf now causes it to revert to its default value (Joachim Wieland)

    Previously, commenting out an entry left the parameter's value unchanged until the next server restart.

E.30.2.3. Character Encodings

  • Add more checks for invalidly-encoded data (Andrew)

    This change plugs some holes that existed in literal backslash escape string processing and COPY escape processing. Now the de-escaped string is rechecked to see if the result created an invalid multi-byte character.

  • Disallow database encodings that are inconsistent with the server's locale setting (Tom)

    On most platforms, C locale is the only locale that will work with any database encoding. Other locale settings imply a specific encoding and will misbehave if the database encoding is something different. (Typical symptoms include bogus textual sort order and wrong results from upper() or lower().) The server now rejects attempts to create databases that have an incompatible encoding.

  • Ensure that chr() cannot create invalidly-encoded values (Andrew)

    In UTF8-encoded databases the argument of chr() is now treated as a Unicode code point. In other multi-byte encodings chr()'s argument must designate a 7-bit ASCII character. Zero is no longer accepted. ascii() has been adjusted to match.

  • Adjust convert() behavior to ensure encoding validity (Andrew)

    The two argument form of convert() has been removed. The three argument form now takes a bytea first argument and returns a bytea. To cover the loss of functionality, three new functions have been added:

    • convert_from(bytea, name) returns text — converts the first argument from the named encoding to the database encoding

    • convert_to(text, name) returns bytea — converts the first argument from the database encoding to the named encoding

    • length(bytea, name) returns integer — gives the length of the first argument in characters in the named encoding

  • Remove convert(argument USING conversion_name) (Andrew)

    Its behavior did not match the SQL standard.

  • Make JOHAB encoding client-only (Tatsuo)

    JOHAB is not safe as a server-side encoding.

E.30.3. Changes

Below you will find a detailed account of the changes between PostgreSQL 8.3 and the previous major release.

E.30.3.1. Performance

  • Asynchronous commit delays writes to WAL during transaction commit (Simon)

    This feature dramatically increases performance for short data-modifying transactions. The disadvantage is that because disk writes are delayed, if the database or operating system crashes before data is written to the disk, committed data will be lost. This feature is useful for applications that can accept some data loss. Unlike turning off fsync, using asynchronous commit does not put database consistency at risk; the worst case is that after a crash the last few reportedly-committed transactions might not be committed after all. This feature is enabled by turning off synchronous_commit (which can be done per-session or per-transaction, if some transactions are critical and others are not). wal_writer_delay can be adjusted to control the maximum delay before transactions actually reach disk.

  • Checkpoint writes can be spread over a longer time period to smooth the I/O spike during each checkpoint (Itagaki Takahiro and Heikki Linnakangas)

    Previously all modified buffers were forced to disk as quickly as possible during a checkpoint, causing an I/O spike that decreased server performance. This new approach spreads out disk writes during checkpoints, reducing peak I/O usage. (User-requested and shutdown checkpoints are still written as quickly as possible.)

  • Heap-Only Tuples (HOT) accelerate space reuse for most UPDATEs and DELETEs (Pavan Deolasee, with ideas from many others)

    UPDATEs and DELETEs leave dead tuples behind, as do failed INSERTs. Previously only VACUUM could reclaim space taken by dead tuples. With HOT dead tuple space can be automatically reclaimed at the time of INSERT or UPDATE if no changes are made to indexed columns. This allows for more consistent performance. Also, HOT avoids adding duplicate index entries.

  • Just-in-time background writer strategy improves disk write efficiency (Greg Smith, Itagaki Takahiro)

    This greatly reduces the need for manual tuning of the background writer.

  • Per-field and per-row storage overhead have been reduced (Greg Stark, Heikki Linnakangas)

    Variable-length data types with data values less than 128 bytes long will see a storage decrease of 3 to 6 bytes. For example, two adjacent char(1) fields now use 4 bytes instead of 16. Row headers are also 4 bytes shorter than before.

  • Using non-persistent transaction IDs for read-only transactions reduces overhead and VACUUM requirements (Florian Pflug)

    Non-persistent transaction IDs do not increment the global transaction counter. Therefore, they reduce the load on pg_clog and increase the time between forced vacuums to prevent transaction ID wraparound. Other performance improvements were also made that should improve concurrency.

  • Avoid incrementing the command counter after a read-only command (Tom)

    There was formerly a hard limit of 232 (4 billion) commands per transaction. Now only commands that actually changed the database count, so while this limit still exists, it should be significantly less annoying.

  • Create a dedicated WAL writer process to off-load work from backends (Simon)

  • Skip unnecessary WAL writes for CLUSTER and COPY (Simon)

    Unless WAL archiving is enabled, the system now avoids WAL writes for CLUSTER and just fsync()s the table at the end of the command. It also does the same for COPY if the table was created in the same transaction.

  • Large sequential scans no longer force out frequently used cached pages (Simon, Heikki, Tom)

  • Concurrent large sequential scans can now share disk reads (Jeff Davis)

    This is accomplished by starting the new sequential scan in the middle of the table (where another sequential scan is already in-progress) and wrapping around to the beginning to finish. This can affect the order of returned rows in a query that does not specify ORDER BY. The synchronize_seqscans configuration parameter can be used to disable this if necessary.

  • ORDER BY ... LIMIT can be done without sorting (Greg Stark)

    This is done by sequentially scanning the table and tracking just the "top N" candidate rows, rather than performing a full sort of the entire table. This is useful when there is no matching index and the LIMIT is not large.

  • Put a rate limit on messages sent to the statistics collector by backends (Tom)

    This reduces overhead for short transactions, but might sometimes increase the delay before statistics are tallied.

  • Improve hash join performance for cases with many NULLs (Tom)

  • Speed up operator lookup for cases with non-exact datatype matches (Tom)

E.30.3.2. Server

  • Autovacuum is now enabled by default (Alvaro)

    Several changes were made to eliminate disadvantages of having autovacuum enabled, thereby justifying the change in default. Several other autovacuum parameter defaults were also modified.

  • Support multiple concurrent autovacuum processes (Alvaro, Itagaki Takahiro)

    This allows multiple vacuums to run concurrently. This prevents vacuuming of a large table from delaying vacuuming of smaller tables.

  • Automatically re-plan cached queries when table definitions change or statistics are updated (Tom)

    Previously PL/pgSQL functions that referenced temporary tables would fail if the temporary table was dropped and recreated between function invocations, unless EXECUTE was used. This improvement fixes that problem and many related issues.

  • Add a temp_tablespaces parameter to control the tablespaces for temporary tables and files (Jaime Casanova, Albert Cervera, Bernd Helmle)

    This parameter defines a list of tablespaces to be used. This enables spreading the I/O load across multiple tablespaces. A random tablespace is chosen each time a temporary object is created. Temporary files are no longer stored in per-database pgsql_tmp/ directories but in per-tablespace directories.

  • Place temporary tables' TOAST tables in special schemas named pg_toast_temp_nnn (Tom)

    This allows low-level code to recognize these tables as temporary, which enables various optimizations such as not WAL-logging changes and using local rather than shared buffers for access. This also fixes a bug wherein backends unexpectedly held open file references to temporary TOAST tables.

  • Fix problem that a constant flow of new connection requests could indefinitely delay the postmaster from completing a shutdown or a crash restart (Tom)

  • Guard against a very-low-probability data loss scenario by preventing re-use of a deleted table's relfilenode until after the next checkpoint (Heikki)

  • Fix CREATE CONSTRAINT TRIGGER to convert old-style foreign key trigger definitions into regular foreign key constraints (Tom)

    This will ease porting of foreign key constraints carried forward from pre-7.3 databases, if they were never converted using contrib/adddepend.

  • Fix DEFAULT NULL to override inherited defaults (Tom)

    DEFAULT NULL was formerly considered a noise phrase, but it should (and now does) override non-null defaults that would otherwise be inherited from a parent table or domain.

  • Add new encodings EUC_JIS_2004 and SHIFT_JIS_2004 (Tatsuo)

    These new encodings can be converted to and from UTF-8.

  • Change server startup log message from "database system is ready" to "database system is ready to accept connections", and adjust its timing

    The message now appears only when the postmaster is really ready to accept connections.

E.30.3.3. Monitoring

  • Add log_autovacuum_min_duration parameter to support configurable logging of autovacuum activity (Simon, Alvaro)

  • Add log_lock_waits parameter to log lock waiting (Simon)

  • Add log_temp_files parameter to log temporary file usage (Bill Moran)

  • Add log_checkpoints parameter to improve logging of checkpoints (Greg Smith, Heikki)

  • log_line_prefix now supports %s and %c escapes in all processes (Andrew)

    Previously these escapes worked only for user sessions, not for background database processes.

  • Add log_restartpoints to control logging of point-in-time recovery restart points (Simon)

  • Last transaction end time is now logged at end of recovery and at each logged restart point (Simon)

  • Autovacuum now reports its activity start time in pg_stat_activity (Tom)

  • Allow server log output in comma-separated value (CSV) format (Arul Shaji, Greg Smith, Andrew Dunstan)

    CSV-format log files can easily be loaded into a database table for subsequent analysis.

  • Use PostgreSQL-supplied timezone support for formatting timestamps displayed in the server log (Tom)

    This avoids Windows-specific problems with localized time zone names that are in the wrong encoding. There is a new log_timezone parameter that controls the timezone used in log messages, independently of the client-visible timezone parameter.

  • New system view pg_stat_bgwriter displays statistics about background writer activity (Magnus)

  • Add new columns for database-wide tuple statistics to pg_stat_database (Magnus)

  • Add an xact_start (transaction start time) column to pg_stat_activity (Neil)

    This makes it easier to identify long-running transactions.

  • Add n_live_tuples and n_dead_tuples columns to pg_stat_all_tables and related views (Glen Parker)

  • Merge stats_block_level and stats_row_level parameters into a single parameter track_counts, which controls all messages sent to the statistics collector process (Tom)

  • Rename stats_command_string parameter to track_activities (Tom)

  • Fix statistical counting of live and dead tuples to recognize that committed and aborted transactions have different effects (Tom)

E.30.3.4. Authentication

  • Support Security Service Provider Interface (SSPI) for authentication on Windows (Magnus)

  • Support GSSAPI authentication (Henry Hotz, Magnus)

    This should be preferred to native Kerberos authentication because GSSAPI is an industry standard.

  • Support a global SSL configuration file (Victor Wagner)

  • Add ssl_ciphers parameter to control accepted SSL ciphers (Victor Wagner)

  • Add a Kerberos realm parameter, krb_realm (Magnus)

E.30.3.5. Write-Ahead Log (WAL) and Continuous Archiving

  • Change the timestamps recorded in transaction WAL records from time_t to TimestampTz representation (Tom)

    This provides sub-second resolution in WAL, which can be useful for point-in-time recovery.

  • Reduce WAL disk space needed by warm standby servers (Simon)

    This change allows a warm standby server to pass the name of the earliest still-needed WAL file to the recovery script, allowing automatic removal of no-longer-needed WAL files. This is done using %r in the restore_command parameter of recovery.conf.

  • New boolean configuration parameter, archive_mode, controls archiving (Simon)

    Previously setting archive_command to an empty string turned off archiving. Now archive_mode turns archiving on and off, independently of archive_command. This is useful for stopping archiving temporarily.

E.30.3.6. Queries

  • Full text search is integrated into the core database system (Teodor, Oleg)

    Text search has been improved, moved into the core code, and is now installed by default. contrib/tsearch2 now contains a compatibility interface.

  • Add control over whether NULLs sort first or last (Teodor, Tom)

    The syntax is ORDER BY ... NULLS FIRST/LAST.

  • Allow per-column ascending/descending (ASC/DESC) ordering options for indexes (Teodor, Tom)

    Previously a query using ORDER BY with mixed ASC/DESC specifiers could not fully use an index. Now an index can be fully used in such cases if the index was created with matching ASC/DESC specifications. NULL sort order within an index can be controlled, too.

  • Allow col IS NULL to use an index (Teodor)

  • Updatable cursors (Arul Shaji, Tom)

    This eliminates the need to reference a primary key to UPDATE or DELETE rows returned by a cursor. The syntax is UPDATE/DELETE WHERE CURRENT OF.

  • Allow FOR UPDATE in cursors (Arul Shaji, Tom)

  • Create a general mechanism that supports casts to and from the standard string types (TEXT, VARCHAR, CHAR) for every datatype, by invoking the datatype's I/O functions (Tom)

    Previously, such casts were available only for types that had specialized function(s) for the purpose. These new casts are assignment-only in the to-string direction, explicit-only in the other direction, and therefore should create no surprising behavior.

  • Allow UNION and related constructs to return a domain type, when all inputs are of that domain type (Tom)

    Formerly, the output would be considered to be of the domain's base type.

  • Allow limited hashing when using two different data types (Tom)

    This allows hash joins, hash indexes, hashed subplans, and hash aggregation to be used in situations involving cross-data-type comparisons, if the data types have compatible hash functions. Currently, cross-data-type hashing support exists for smallint/integer/bigint, and for float4/float8.

  • Improve optimizer logic for detecting when variables are equal in a WHERE clause (Tom)

    This allows mergejoins to work with descending sort orders, and improves recognition of redundant sort columns.

  • Improve performance when planning large inheritance trees in cases where most tables are excluded by constraints (Tom)

E.30.3.7. Object Manipulation

  • Arrays of composite types (David Fetter, Andrew, Tom)

    In addition to arrays of explicitly-declared composite types, arrays of the rowtypes of regular tables and views are now supported, except for rowtypes of system catalogs, sequences, and TOAST tables.

  • Server configuration parameters can now be set on a per-function basis (Tom)

    For example, functions can now set their own search_path to prevent unexpected behavior if a different search_path exists at run-time. Security definer functions should set search_path to avoid security loopholes.

  • CREATE/ALTER FUNCTION now supports COST and ROWS options (Tom)

    COST allows specification of the cost of a function call. ROWS allows specification of the average number or rows returned by a set-returning function. These values are used by the optimizer in choosing the best plan.

  • Implement CREATE TABLE LIKE ... INCLUDING INDEXES (Trevor Hardcastle, Nikhil Sontakke, Neil)

  • Allow CREATE INDEX CONCURRENTLY to ignore transactions in other databases (Simon)

  • Add ALTER VIEW ... RENAME TO and ALTER SEQUENCE ... RENAME TO (David Fetter, Neil)

    Previously this could only be done via ALTER TABLE ... RENAME TO.

  • Make CREATE/DROP/RENAME DATABASE wait briefly for conflicting backends to exit before failing (Tom)

    This increases the likelihood that these commands will succeed.

  • Allow triggers and rules to be deactivated in groups using a configuration parameter, for replication purposes (Jan)

    This allows replication systems to disable triggers and rewrite rules as a group without modifying the system catalogs directly. The behavior is controlled by ALTER TABLE and a new parameter session_replication_role.

  • User-defined types can now have type modifiers (Teodor, Tom)

    This allows a user-defined type to take a modifier, like ssnum(7). Previously only built-in data types could have modifiers.

E.30.3.8. Utility Commands

  • Non-superuser database owners now are able to add trusted procedural languages to their databases by default (Jeremy Drake)

    While this is reasonably safe, some administrators might wish to revoke the privilege. It is controlled by pg_pltemplate.tmpldbacreate.

  • Allow a session's current parameter setting to be used as the default for future sessions (Tom)

    This is done with SET ... FROM CURRENT in CREATE/ALTER FUNCTION, ALTER DATABASE, or ALTER ROLE.

  • Implement new commands DISCARD ALL, DISCARD PLANS, DISCARD TEMPORARY, CLOSE ALL, and DEALLOCATE ALL (Marko Kreen, Neil)

    These commands simplify resetting a database session to its initial state, and are particularly useful for connection-pooling software.

  • Make CLUSTER MVCC-safe (Heikki Linnakangas)

    Formerly, CLUSTER would discard all tuples that were committed dead, even if there were still transactions that should be able to see them under MVCC visibility rules.

  • Add new CLUSTER syntax: CLUSTER table USING index (Holger Schurig)

    The old CLUSTER syntax is still supported, but the new form is considered more logical.

  • Fix EXPLAIN so it can show complex plans more accurately (Tom)

    References to subplan outputs are now always shown correctly, instead of using ?columnN? for complicated cases.

  • Limit the amount of information reported when a user is dropped (Alvaro)

    Previously, dropping (or attempting to drop) a user who owned many objects could result in large NOTICE or ERROR messages listing all these objects; this caused problems for some client applications. The length of the message is now limited, although a full list is still sent to the server log.

E.30.3.9. Data Types

  • Support for the SQL/XML standard, including new operators and an XML data type (Nikolay Samokhvalov, Pavel Stehule, Peter)

  • Enumerated data types (ENUM) (Tom Dunstan)

    This feature provides convenient support for fields that have a small, fixed set of allowed values. An example of creating an ENUM type is CREATE TYPE mood AS ENUM ('sad', 'ok', 'happy').

  • Universally Unique Identifier (UUID) data type (Gevik Babakhani, Neil)

    This closely matches RFC 4122.

  • Widen the MONEY data type to 64 bits (D'Arcy Cain)

    This greatly increases the range of supported MONEY values.

  • Fix float4/float8 to handle Infinity and NAN (Not A Number) consistently (Bruce)

    The code formerly was not consistent about distinguishing Infinity from overflow conditions.

  • Allow leading and trailing whitespace during input of boolean values (Neil)

  • Prevent COPY from using digits and lowercase letters as delimiters (Tom)

E.30.3.10. Functions

  • Add new regular expression functions regexp_matches(), regexp_split_to_array(), and regexp_split_to_table() (Jeremy Drake, Neil)

    These functions provide extraction of regular expression subexpressions and allow splitting a string using a POSIX regular expression.

  • Add lo_truncate() for large object truncation (Kris Jurka)

  • Implement width_bucket() for the float8 data type (Neil)

  • Add pg_stat_clear_snapshot() to discard statistics snapshots collected during the current transaction (Tom)

    The first request for statistics in a transaction takes a statistics snapshot that does not change during the transaction. This function allows the snapshot to be discarded and a new snapshot loaded during the next statistics query. This is particularly useful for PL/pgSQL functions, which are confined to a single transaction.

  • Add isodow option to EXTRACT() and date_part() (Bruce)

    This returns the day of the week, with Sunday as seven. (dow returns Sunday as zero.)

  • Add ID (ISO day of week) and IDDD (ISO day of year) format codes for to_char(), to_date(), and to_timestamp() (Brendan Jurd)

  • Make to_timestamp() and to_date() assume TM (trim) option for potentially variable-width fields (Bruce)

    This matches Oracle's behavior.

  • Fix off-by-one conversion error in to_date()/to_timestamp() D (non-ISO day of week) fields (Bruce)

  • Make setseed() return void, rather than a useless integer value (Neil)

  • Add a hash function for NUMERIC (Neil)

    This allows hash indexes and hash-based plans to be used with NUMERIC columns.

  • Improve efficiency of LIKE/ILIKE, especially for multi-byte character sets like UTF-8 (Andrew, Itagaki Takahiro)

  • Make currtid() functions require SELECT privileges on the target table (Tom)

  • Add several txid_*() functions to query active transaction IDs (Jan)

    This is useful for various replication solutions.

E.30.3.11. PL/pgSQL Server-Side Language

  • Add scrollable cursor support, including directional control in FETCH (Pavel Stehule)

  • Allow IN as an alternative to FROM in PL/pgSQL's FETCH statement, for consistency with the backend's FETCH command (Pavel Stehule)

  • Add MOVE to PL/pgSQL (Magnus, Pavel Stehule, Neil)

  • Implement RETURN QUERY (Pavel Stehule, Neil)

    This adds convenient syntax for PL/pgSQL set-returning functions that want to return the result of a query. RETURN QUERY is easier and more efficient than a loop around RETURN NEXT.

  • Allow function parameter names to be qualified with the function's name (Tom)

    For example, myfunc.myvar. This is particularly useful for specifying variables in a query where the variable name might match a column name.

  • Make qualification of variables with block labels work properly (Tom)

    Formerly, outer-level block labels could unexpectedly interfere with recognition of inner-level record or row references.

  • Tighten requirements for FOR loop STEP values (Tom)

    Prevent non-positive STEP values, and handle loop overflows.

  • Improve accuracy when reporting syntax error locations (Tom)

E.30.3.12. Other Server-Side Languages

  • Allow type-name arguments to PL/Perl spi_prepare() to be data type aliases in addition to names found in pg_type (Andrew)

  • Allow type-name arguments to PL/Python plpy.prepare() to be data type aliases in addition to names found in pg_type (Andrew)

  • Allow type-name arguments to PL/Tcl spi_prepare to be data type aliases in addition to names found in pg_type (Andrew)

  • Enable PL/PythonU to compile on Python 2.5 (Marko Kreen)

  • Support a true PL/Python boolean type in compatible Python versions (Python 2.3 and later) (Marko Kreen)

  • Fix PL/Tcl problems with thread-enabled libtcl spawning multiple threads within the backend (Steve Marshall, Paul Bayer, Doug Knight)

    This caused all sorts of unpleasantness.

E.30.3.13. psql

  • List disabled triggers separately in \d output (Brendan Jurd)

  • In \d patterns, always match $ literally (Tom)

  • Show aggregate return types in \da output (Greg Sabino Mullane)

  • Add the function's volatility status to the output of \df+ (Neil)

  • Add \prompt capability (Chad Wagner)

  • Allow \pset, \t, and \x to specify on or off, rather than just toggling (Chad Wagner)

  • Add \sleep capability (Jan)

  • Enable \timing output for \copy (Andrew)

  • Improve \timing resolution on Windows (Itagaki Takahiro)

  • Flush \o output after each backslash command (Tom)

  • Correctly detect and report errors while reading a -f input file (Peter)

  • Remove -u option (this option has long been deprecated) (Tom)

E.30.3.14. pg_dump

  • Add --tablespaces-only and --roles-only options to pg_dumpall (Dave Page)

  • Add an output file option to pg_dumpall (Dave Page)

    This is primarily useful on Windows, where output redirection of child pg_dump processes does not work.

  • Allow pg_dumpall to accept an initial-connection database name rather than the default template1 (Dave Page)

  • In -n and -t switches, always match $ literally (Tom)

  • Improve performance when a database has thousands of objects (Tom)

  • Remove -u option (this option has long been deprecated) (Tom)

E.30.3.15. Other Client Applications

  • In initdb, allow the location of the pg_xlog directory to be specified (Euler Taveira de Oliveira)

  • Enable server core dump generation in pg_regress on supported operating systems (Andrew)

  • Add a -t (timeout) parameter to pg_ctl (Bruce)

    This controls how long pg_ctl will wait when waiting for server startup or shutdown. Formerly the timeout was hard-wired as 60 seconds.

  • Add a pg_ctl option to control generation of server core dumps (Andrew)

  • Allow Control-C to cancel clusterdb, reindexdb, and vacuumdb (Itagaki Takahiro, Magnus)

  • Suppress command tag output for createdb, createuser, dropdb, and dropuser (Peter)

    The --quiet option is ignored and will be removed in 8.4. Progress messages when acting on all databases now go to stdout instead of stderr because they are not actually errors.

E.30.3.16. libpq

  • Interpret the dbName parameter of PQsetdbLogin() as a conninfo string if it contains an equals sign (Andrew)

    This allows use of conninfo strings in client programs that still use PQsetdbLogin().

  • Support a global SSL configuration file (Victor Wagner)

  • Add environment variable PGSSLKEY to control SSL hardware keys (Victor Wagner)

  • Add lo_truncate() for large object truncation (Kris Jurka)

  • Add PQconnectionNeedsPassword() that returns true if the server required a password but none was supplied (Joe Conway, Tom)

    If this returns true after a failed connection attempt, a client application should prompt the user for a password. In the past applications have had to check for a specific error message string to decide whether a password is needed; that approach is now deprecated.

  • Add PQconnectionUsedPassword() that returns true if the supplied password was actually used (Joe Conway, Tom)

    This is useful in some security contexts where it is important to know whether a user-supplied password is actually valid.

E.30.3.17. ecpg

  • Use V3 frontend/backend protocol (Michael)

    This adds support for server-side prepared statements.

  • Use native threads, instead of pthreads, on Windows (Magnus)

  • Improve thread-safety of ecpglib (Itagaki Takahiro)

  • Make the ecpg libraries export only necessary API symbols (Michael)

E.30.3.18. Windows Port

  • Allow the whole PostgreSQL distribution to be compiled with Microsoft Visual C++ (Magnus and others)

    This allows Windows-based developers to use familiar development and debugging tools. Windows executables made with Visual C++ might also have better stability and performance than those made with other tool sets. The client-only Visual C++ build scripts have been removed.

  • Drastically reduce postmaster's memory usage when it has many child processes (Magnus)

  • Allow regression tests to be started by an administrative user (Magnus)

  • Add native shared memory implementation (Magnus)

E.30.3.19. Server Programming Interface (SPI)

  • Add cursor-related functionality in SPI (Pavel Stehule)

    Allow access to the cursor-related planning options, and add FETCH/MOVE routines.

  • Allow execution of cursor commands through SPI_execute (Tom)

    The macro SPI_ERROR_CURSOR still exists but will never be returned.

  • SPI plan pointers are now declared as SPIPlanPtr instead of void * (Tom)

    This does not break application code, but switching is recommended to help catch simple programming mistakes.

E.30.3.20. Build Options

  • Add configure option --enable-profiling to enable code profiling (works only with gcc) (Korry Douglas and Nikhil Sontakke)

  • Add configure option --with-system-tzdata to use the operating system's time zone database (Peter)

  • Fix PGXS so extensions can be built against PostgreSQL installations whose pg_config program does not appear first in the PATH (Tom)

  • Support gmake draft when building the SGML documentation (Bruce)

    Unless draft is used, the documentation build will now be repeated if necessary to ensure the index is up-to-date.

E.30.3.21. Source Code

  • Rename macro DLLIMPORT to PGDLLIMPORT to avoid conflicting with third party includes (like Tcl) that define DLLIMPORT (Magnus)

  • Create "operator families" to improve planning of queries involving cross-data-type comparisons (Tom)

  • Update GIN extractQuery() API to allow signalling that nothing can satisfy the query (Teodor)

  • Move NAMEDATALEN definition from postgres_ext.h to pg_config_manual.h (Peter)

  • Provide strlcpy() and strlcat() on all platforms, and replace error-prone uses of strncpy(), strncat(), etc (Peter)

  • Create hooks to let an external plugin monitor (or even replace) the planner and create plans for hypothetical situations (Gurjeet Singh, Tom)

  • Create a function variable join_search_hook to let plugins override the join search order portion of the planner (Julius Stroffek)

  • Add tas() support for Renesas' M32R processor (Kazuhiro Inaoka)

  • quote_identifier() and pg_dump no longer quote keywords that are unreserved according to the grammar (Tom)

  • Change the on-disk representation of the NUMERIC data type so that the sign_dscale word comes before the weight (Tom)

  • Use SYSV semaphores rather than POSIX on Darwin >= 6.0, i.e., OS X 10.2 and up (Chris Marcellino)

  • Add acronym and NFS documentation sections (Bruce)

  • "Postgres" is now documented as an accepted alias for "PostgreSQL" (Peter)

  • Add documentation about preventing database server spoofing when the server is down (Bruce)

E.30.3.22. Contrib

  • Move contrib README content into the main PostgreSQL documentation (Albert Cervera i Areny)

  • Add contrib/pageinspect module for low-level page inspection (Simon, Heikki)

  • Add contrib/pg_standby module for controlling warm standby operation (Simon)

  • Add contrib/uuid-ossp module for generating UUID values using the OSSP UUID library (Peter)

    Use configure --with-ossp-uuid to activate. This takes advantage of the new UUID builtin type.

  • Add contrib/dict_int, contrib/dict_xsyn, and contrib/test_parser modules to provide sample add-on text search dictionary templates and parsers (Sergey Karpov)

  • Allow contrib/pgbench to set the fillfactor (Pavan Deolasee)

  • Add timestamps to contrib/pgbench -l (Greg Smith)

  • Add usage count statistics to contrib/pgbuffercache (Greg Smith)

  • Add GIN support for contrib/hstore (Teodor)

  • Add GIN support for contrib/pg_trgm (Guillaume Smet, Teodor)

  • Update OS/X startup scripts in contrib/start-scripts (Mark Cotner, David Fetter)

  • Restrict pgrowlocks() and dblink_get_pkey() to users who have SELECT privilege on the target table (Tom)

  • Restrict contrib/pgstattuple functions to superusers (Tom)

  • contrib/xml2 is deprecated and planned for removal in 8.4 (Peter)

    The new XML support in core PostgreSQL supersedes this module.

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