PostgreSQL 9.4.4, 9.3.9, 9.2.13, 9.1.18 & 9.0.22 發布
PostgreSQL是以加州大學伯克利分校計算機系開發的 POSTGRES，現在已經更名為PostgreSQL，版本 4.2為基礎的對象關系型數據庫管理系統（ORDBMS）。PostgreSQL支持大部分 SQL標準并且提供了許多其他現代特性：復雜查詢、外鍵、觸發器、視圖、事務完整性、MVCC。同樣，PostgreSQL 可以用許多方法擴展，比如， 通過增加新的數據類型、函數、操作符、聚集函數、索引。免費使用、修改、和分發 PostgreSQL，不管是私用、商用、還是學術研究使用。
PostgreSQL主要優勢：
1.
PostgreSQL完全免費，而且是BSD協議，如果你把PostgreSQL改一改，然后再拿去賣錢，也沒有人管你，這一點很重要，這表明了
PostgreSQL數據庫不會被其它公司控制。oracle數據庫不用說了，是商業數據庫，不開放。而MySQL數據庫雖然是開源的，但現在隨著SUN
被oracle公司收購，現在基本上被oracle公司控制，其實在SUN被收購之前，MySQL中最重要的InnoDB引擎也是被oracle公司控制
的，而在MySQL中很多重要的數據都是放在InnoDB引擎中的，反正我們公司都是這樣的。所以如果MySQL的市場范圍與oracle數據庫的市場范
圍沖突時，oracle公司必定會犧牲MySQL，這是毫無疑問的。
2. 與PostgreSQl配合的開源軟件很多，有很多分布式集群軟件，如pgpool、pgcluster、slony、plploxy等等，很容易做讀寫分離、負載均衡、數據水平拆分等方案，而這在MySQL下則比較困難。
3. PostgreSQL源代碼寫的很清晰，易讀性比MySQL強太多了，懷疑MySQL的源代碼被混淆過。所以很多公司都是基本PostgreSQL做二次開發的。
4.
PostgreSQL在很多方面都比MySQL強，如復雜SQL的執行、存儲過程、觸發器、索引。同時PostgreSQL是多進程的，而MySQL是線
程的，雖然并發不高時，MySQL處理速度快，但當并發高的時候，對于現在多核的單臺機器上，MySQL的總體處理性能不如PostgreSQL，原因是
MySQL的線程無法充分利用CPU的能力。
PostgreSQL 9.4.4, 9.3.9, 9.2.13, 9.1.18 & 9.0.22 發布，這些版本主要是一些 bug 修復，建議用戶更新。
The PostgreSQL Global Development Group has released an update to all supported versions of our database system, including 9.4.4, 9.3.9, 9.2.13, 9.1.18 and 9.0.22. This release primarily fixes issues not successfully fixed in prior releases. It should be applied as soon as possible all users of major versions 9.3 and 9.4. Other users should apply at the next available downtime.
Crash Recovery Fixes
Earlier update releases attempted to fix an issue in PostgreSQL 9.3 and 9.4 with "multixact wraparound", but failed to account for issues doing multixact cleanup during crash recovery. This could cause servers to be unable to restart after a crash. As such, all users of 9.3 and 9.4 should apply this update as soon as possible.
Servers previously upgraded to PostgreSQL 9.3 using pg_upgrade, even those servers now running PostgreSQL 9.4 due to another upgrade, may experience an immediate autovacuum of all tables after applying this update. For large databases, consider a controlled manual VACUUM, before updating, to better regulate the performance consequences of this critical maintenance. Please see the release notes for details.
Other Fixes and Improvements
In addition to the above, a few other minor issues were patched in this release. These fixes include:
- Prevent failure to invalidate relation cache init file
- Avoid deadlock between new sessions and CREATE/DROP DATABASE
- Improve query planning for semi-joins and anti-joins
Cumulative Releases
All PostgreSQL update releases are cumulative. As this update release fixes a number of problems inadvertently introduced by fixes in earlier update releases, we strongly urge users to apply this update, rather than installing less recent updates that have known issues. As this update release closes multiple known bugs with multixact handling, the PostgreSQL Project does not anticipate additional update releases soon.
Updating
As with other minor releases, users are not required to dump and reload their database or use pg_upgrade in order to apply this update release; you may simply shut down PostgreSQL and update its binaries. Users who have skipped multiple update releases may need to perform additional post-update steps; see the Release Notes for details. See also the above note for users who used pg_upgrade with PostgreSQL version 9.3.
Links: