PostgreSQL 9.1.2

PostgreSQL 是一款功能強大、開放原始碼的物件關聯式資料庫系統。它歷經超過 15 年的積極開發，其成熟的架構為可靠性、資料完整性與正確性贏得了良好聲譽。

它可在所有主流作業系統上執行，包括 Linux、UNIX（AIX、BSD、HP-UX、SGI IRIX、macOS、Solaris、Tru64）以及 Windows。PostgreSQL 是一款強大的物件關聯式資料庫管理系統！下載適用於 PC 的 PostgreSQL 離線安裝程式 64 位元版本！

它完全符合 ACID 規範，並完整支援外部鍵、聯結、檢視、觸發器以及預存程序（支援多種語言）。它包含大多數 SQL:2008 資料型別，包括 INTEGER、NUMERIC、BOOLEAN、CHAR、VARCHAR、DATE、INTERVAL 和 TIMESTAMP。

它也支援儲存二進位大型物件，包括圖片、音訊或影片。它具備 C/C++、Java、.Net、Perl、Python、Ruby、Tcl、ODBC 等原生程式設計介面，並提供卓越的文件（資料表大小最高可達 32 TB）。

PostgreSQL 2026 具備許多功能，旨在協助開發人員建置應用程式、協助管理員保護資料完整性並建置容錯環境，同時協助您管理任何規模的資料集。除了免費且開放原始碼之外，這款工具還具有高度擴充性。

例如，您可以定義自己的資料型別、建立自訂函式，甚至使用不同的程式語言撰寫程式碼，而無需重新編譯資料庫！

此應用程式力求在符合 SQL 標準的同時，不與傳統功能牴觸，也不會導致不良的架構決策。

SQL 標準要求的許多功能都已支援，不過有時語法或功能會略有差異。未來可望進一步提升標準符合度。

功能與重點

資料型別

• 基本型別：整數、數值、字串、布林值
• 結構化：日期/時間、陣列、範圍、UUID
• 文件型別：JSON/JSONB、XML、鍵值對（Hstore）
• 幾何型別：點、線、圓、多邊形
• 自訂：複合型別、自訂型別

資料完整性

• UNIQUE、NOT NULL
• 主鍵
• 外部鍵
• 排除約束
• 明確鎖定、建議鎖定

並行性與效能

• 索引：B-tree、多欄位、運算式、部分索引
• 進階索引：GiST、SP-GiST、KNN GiST、GIN、BRIN、涵蓋索引、布隆過濾器
• 精密的查詢規劃器/最佳化器、僅索引掃描、多欄位統計
• 交易、巢狀交易（透過儲存點）
• 多版本並行控制（MVCC）
• 讀取查詢與建立 B-tree 索引的平行化
• 資料表分割
• SQL 標準定義的所有交易隔離層級，包括可序列化
• 運算式的即時（JIT）編譯

可靠性與災難復原

• 預寫式記錄（WAL）
• 複寫：非同步、同步、邏輯
• 時間點復原（PITR）、主動備援
• 資料表空間

安全性

• 驗證：GSSAPI、SSPI、LDAP、SCRAM-SHA-256、憑證等
• 健全的存取控制系統
• 欄位與列層級安全性

擴充性

• 預存函式與程序
• 程序語言：PL/pgSQL、Perl、Python（以及更多）
• 外部資料包裝器：透過標準 SQL 介面連線至其他資料庫或串流
• 許多提供額外功能的擴充套件，包括 PostGIS

國際化與全文檢索

• 支援國際字元集，例如透過 ICU 定序
• 全文檢索

使用方式

• 從官方網站或 FileHorse.com 下載並安裝此程式
• 開啟 pgAdmin 或使用命令列進行資料庫管理
• 使用 pgAdmin 介面建立新資料庫
• 使用 SQL 查詢來建立、讀取、更新和刪除資料
• 設定使用者角色與權限以確保安全性
• 使用 pgAdmin 或命令列備份與還原資料庫
• 使用索引與查詢調校來最佳化效能
• 使用 PostgreSQL 相容驅動程式連線應用程式
• 使用內建記錄工具監控資料庫活動
• 保持 PostgreSQL 更新以確保安全性與效能

系統需求

作業系統：Windows 11 或 Windows 10（64 位元）

處理器：Intel 或 AMD 64 位元處理器

記憶體：最低 2GB，建議 4GB 或以上

儲存空間：安裝至少需要 100MB，資料儲存另需更多空間

其他需求：需要 Microsoft Visual C++ 可轉散發套件

優點

• 開放原始碼且免費使用
• 進階安全性功能
• 高擴充性與效能
• 支援複雜查詢與索引
• 強大的社群與文件

缺點

• 需要手動效能調校
• 某些情況下記憶體使用量較高
• 內建 GUI 管理工具有限
• 升級可能需要手動調整

另有提供：下載 PostgreSQL for Mac

下載 PostgreSQL 最新版本 為什麼此應用程式發佈在 FileHorse 上？（更多資訊）

* Fix bugs in information_schema.referential_constraints view
- This view was being insufficiently careful about matching the foreign-key constraint to the depended-on primary or unique key constraint. That could result in failure to show a foreign key constraint at all, or showing it multiple times, or claiming that it depends on a different constraint than the one it really does.
- Since the view definition is installed by initdb, merely upgrading will not fix the problem. If you need to fix this in an existing installation, you can (as a superuser) drop the information_schema schema then re-create it by sourcing SHAREDIR/information_schema.sql. (Run pg_config --sharedir if you're uncertain where SHAREDIR is.) This must be repeated in each database to be fixed.
* Make contrib/citext's upgrade script fix collations of citext columns and indexes
- Existing citext columns and indexes aren't correctly marked as being of a collatable data type during pg_upgrade from a pre-9.1 server. That leads to operations on them failing with errors such as "could not determine which collation to use for string comparison". This change allows them to be fixed by the same script that upgrades the citext module into a proper 9.1 extension during CREATE EXTENSION citext FROM unpackaged.
- If you have a previously-upgraded database that is suffering from this problem, and you already ran the CREATE EXTENSION command, you can manually run (as superuser) the UPDATE commands found at the end of SHAREDIR/extension/citext--unpackaged--1.0.sql. (Run pg_config --sharedir if you're uncertain where SHAREDIR is.)
* Fix possible crash during UPDATE or DELETE that joins to the output of a scalar-returning function
- A crash could only occur if the target row had been concurrently updated, so this problem surfaced only intermittently.
* Fix incorrect replay of WAL records for GIN index updates
- This could result in transiently failing to find index entries after a crash, or on a hot-standby server. The problem would be repaired by the next VACUUM of the index, however.
* Fix TOAST-related data corruption during CREATE TABLE dest AS SELECT * FROM src or INSERT INTO dest SELECT * FROM src
- If a table has been modified by ALTER TABLE ADD COLUMN, attempts to copy its data verbatim to another table could produce corrupt results in certain corner cases. The problem can only manifest in this precise form in 8.4 and later, but we patched earlier versions as well in case there are other code paths that could trigger the same bug.
* Fix possible failures during hot standby startup
* Start hot standby faster when initial snapshot is incomplete
* Fix race condition during toast table access from stale syscache entries
- The typical symptom was transient errors like "missing chunk number 0 for toast value NNNNN in pg_toast_2619", where the cited toast table would always belong to a system catalog.
* Track dependencies of functions on items used in parameter default expressions
- Previously, a referenced object could be dropped without having dropped or modified the function, leading to misbehavior when the function was used. Note that merely installing this update will not fix the missing dependency entries; to do that, you'd need to CREATE OR REPLACE each such function afterwards. If you have functions whose defaults depend on non-built-in objects, doing so is recommended.
* Fix incorrect management of placeholder variables in nestloop joins
- This bug is known to lead to "variable not found in subplan target list" planner errors, and could possibly result in wrong query output when outer joins are involved.
* Fix window functions that sort by expressions involving aggregates
- Previously these could fail with "could not find pathkey item to sort" planner errors.
* Fix "MergeAppend child's targetlist doesn't match MergeAppend" planner errors
* Fix index matching for operators with both collatable and noncollatable inputs
- In 9.1.0, an indexable operator that has a non-collatable left-hand input type and a collatable right-hand input type would not be recognized as matching the left-hand column's index. An example is the hstore ? text operator.
* Allow inlining of set-returning SQL functions with multiple OUT parameters
* Don't trust deferred-unique indexes for join removal
- A deferred uniqueness constraint might not hold intra-transaction, so assuming that it does could give incorrect query results.
* Make DatumGetInetP() unpack inet datums that have a 1-byte header, and add a new macro, DatumGetInetPP(), that does not
- This change affects no core code, but might prevent crashes in add-on code that expects DatumGetInetP() to produce an unpacked datum as per usual convention.
* Improve locale support in money type's input and output
- Aside from not supporting all standard lc_monetary formatting options, the input and output functions were inconsistent, meaning there were locales in which dumped money values could not be re-read.
* Don't let transform_null_equals affect CASE foo WHEN NULL ... constructs
- transform_null_equals is only supposed to affect foo = NULL expressions written directly by the user, not equality checks generated internally by this form of CASE.
* Change foreign-key trigger creation order to better support self-referential foreign keys
- For a cascading foreign key that references its own table, a row update will fire both the ON UPDATE trigger and the CHECK trigger as one event. The ON UPDATE trigger must execute first, else the CHECK will check a non-final state of the row and possibly throw an inappropriate error. However, the firing order of these triggers is determined by their names, which generally sort in creation order since the triggers have auto-generated names following the convention "RI_ConstraintTrigger_NNNN". A proper fix would require modifying that convention, which we will do in 9.2, but it seems risky to change it in existing releases. So this patch just changes the creation order of the triggers. Users encountering this type of error should drop and re-create the foreign key constraint to get its triggers into the right order.
* Fix IF EXISTS to work correctly in DROP OPERATOR FAMILY
* Disallow dropping of an extension from within its own script
- This prevents odd behavior in case of incorrect management of extension dependencies.
* Don't mark auto-generated types as extension members
- Relation rowtypes and automatically-generated array types do not need to have their own extension membership entries in pg_depend, and creating such entries complicates matters for extension upgrades.
* Cope with invalid pre-existing search_path settings during CREATE EXTENSION
* Avoid floating-point underflow while tracking buffer allocation rate
- While harmless in itself, on certain platforms this would result in annoying kernel log messages.
* Prevent autovacuum transactions from running in serializable mode
- Autovacuum formerly used the cluster-wide default transaction isolation level, but there is no need for it to use anything higher than READ COMMITTED, and using SERIALIZABLE could result in unnecessary delays for other processes.
* Ensure walsender processes respond promptly to SIGTERM
* Exclude postmaster.opts from base backups
* Preserve configuration file name and line number values when starting child processes under Windows
- Formerly, these would not be displayed correctly in the pg_settings view.
* Fix incorrect field alignment in ecpg's SQLDA area
* Preserve blank lines within commands in psql's command history
- The former behavior could cause problems if an empty line was removed from within a string literal, for example.
* Avoid platform-specific infinite loop in pg_dump
* Fix compression of plain-text output format in pg_dump
- pg_dump has historically understood -Z with no -F switch to mean that it should emit a gzip-compressed version of its plain text output. Restore that behavior.
* Fix pg_dump to dump user-defined casts between auto-generated types, such as table rowtypes
* Fix missed quoting of foreign server names in pg_dump
* Assorted fixes for pg_upgrade
- Handle exclusion constraints correctly, avoid failures on Windows, don't complain about mismatched toast table names in 8.4 databases.
* In PL/pgSQL, allow foreign tables to define row types
* Fix up conversions of PL/Perl functions' results
- Restore the pre-9.1 behavior that PL/Perl functions returning void ignore the result value of their last Perl statement; 9.1.0 would throw an error if that statement returned a reference. Also, make sure it works to return a string value for a composite type, so long as the string meets the type's input format. In addition, throw errors for attempts to return Perl arrays or hashes when the function's declared result type is not an array or composite type, respectively. (Pre-9.1 versions rather uselessly returned strings like ARRAY(0x221a9a0) or HASH(0x221aa90) in such cases.)
* Ensure PL/Perl strings are always correctly UTF8-encoded
* Use the preferred version of xsubpp to build PL/Perl, not necessarily the operating system's main copy
* Correctly propagate SQLSTATE in PL/Python exceptions
* Do not install PL/Python extension files for Python major versions other than the one built against
* Change all the contrib extension script files to report a useful error message if they are fed to psql
- This should help teach people about the new method of using CREATE EXTENSION to load these files. In most cases, sourcing the scripts directly would fail anyway, but with harder-to-interpret messages.
* Fix incorrect coding in contrib/dict_int and contrib/dict_xsyn
- Some functions incorrectly assumed that memory returned by palloc() is guaranteed zeroed.
* Remove contrib/sepgsql tests from the regular regression test mechanism
- Since these tests require root privileges for setup, they're impractical to run automatically. Switch over to a manual approach instead, and provide a testing script to help with that.
* Fix assorted errors in contrib/unaccent's configuration file parsing
* Honor query cancel interrupts promptly in pgstatindex()
* Fix incorrect quoting of log file name in Mac OS X start script
* Revert unintentional enabling of WAL_DEBUG
- Fortunately, as debugging tools go, this one is pretty cheap; but it's not intended to be enabled by default, so revert.
* Ensure VPATH builds properly install all server header files
* Shorten file names reported in verbose error messages
- Regular builds have always reported just the name of the C file containing the error message call, but VPATH builds formerly reported an absolute path name.
* Fix interpretation of Windows timezone names for Central America
- Map "Central America Standard Time" to CST6, not CST6CDT, because DST is generally not observed anywhere in Central America.
* Update time zone data files to tzdata release 2011n for DST law changes in Brazil, Cuba, Fiji, Palestine, Russia, and Samoa; also historical corrections for Alaska and British East Africa.