PCLabs Survey, Part II: Server Engine
От | The Hermit Hacker |
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Тема | PCLabs Survey, Part II: Server Engine |
Дата | |
Msg-id | Pine.BSF.4.21.0001311734430.480-100000@thelab.hub.org обсуждение исходный текст |
Список | pgsql-hackers |
Server Engine - units of execution (granularity of multi-tasking engine) - computes statistics while building index - can run operations without logging - can undo database structure modification (Data Definition Layer) commands - can undo committed transactions if required - locking - levels of locking granulatity available (options are row, page, table,etc.) - default locking levelfor queries - readers of data can block writers of data (at default locking level) - writers of data canblock readers of data (at default locking level) - can use different types of locks on index and data pages in onequery - can escalate many fine-grained locks to one coarser lock - can use multiple CPUs - within a query (intra-query parallelism) - on database load - on database index - on database backup and restore - on insert ... select ... - on update - on delete - join and index selection - joins - nested loop join - hash join - mergejoin - semi-join for star queries - list any others: - indicies - B-tree - clustered (data pages ordered by primary key value) - allow secondary indices on a clusteredindex table - bitmap - hash - list any others: - can scanindices in reverse - optimizer - cost-based - rule-based - can use multiple indices in a single query - can use justthe index to satisfy the query (covered indices) - automatically maintains necessary optimizer statistics - cache and memory management - dynamic SQL statements parameterized and cached for later use - execution planscan be compiled once and then shared among all users - can define dedicated caches for particular tables or tablespaces - can mark tables as memory-resident - dynamic memory resource sharing (e.g. cache can grow or shrink) - scalability - number of CPUs supported per server - multi-machine clustering for performance - clustered servers require shared disk subsystem - clustered machines can run different operating systems - availability - failover server option - primary and standby servers require shared disk subsystem oronly a shared network connection - primary and standby servers can run different operating systems - failover server can be actively used (active/active configuration) - client connection librariessupport automatic failover to standby server - ability to guarantee service (QoS) - query resourceconsumption governor - can assign priorities to different groups of users - backup and restore - restore to a particular point-in-time (partial restore) - incremental backup - recovery - can control frequency of checkpointing by number of operations or estimated recovery time (list which) - storage engine - default disk data block size - users can choose disk block size (list options) - allowuse of unformatted disks for extra speed - parallel disk operations - automatic disk read-ahead -multi-task (asynchronous) disk operations - data and log devices can grow when needed - Year 2000 certified - Euro currency support Marc G. Fournier ICQ#7615664 IRC Nick: Scrappy Systems Administrator @ hub.org primary: scrappy@hub.org secondary: scrappy@{freebsd|postgresql}.org
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