亚洲春色欧美激情

<form id=WZeJxaBel><nobr id=WZeJxaBel></nobr></form>

<address id=WZeJxaBel><nobr id=WZeJxaBel><nobr id=WZeJxaBel></nobr></nobr></address>

首頁 > 數據庫 > 詳細

SQL Server 2014新特性——Buffer Pool擴展

時間：2014-04-30 02:27:46 阅读：716 評論：0 收藏：0 [點我收藏+]

標簽：des com http blog style class div img size log c

Buffer Pool擴展

Buffer Pool擴展是buffer pool 和非易失的SSD硬盤做連接。以SSD硬盤的特點來提高隨機讀性能。

缓冲池擴展优点

SQL Server讀以隨機讀爲主，SQL Server IO分爲2部分：buffer pool管理方式，和buffer pool。

SQL Server 從磁盤中讀入數據，並且存放在buffer pool中以供讀取和修改，修改完之後髒數據還是放在buffer pool中，當內存緊張執行lazy write把髒數據寫入磁盤，並且釋放內存頁。要用時又會從磁盤中讀取，這樣無形中加大了對io的需求。

SQL Server 2014之前解決方法：加內存，減少對IO的需求

SQL Server 2014解決辦法：使用buffer pool擴展，加入SSD硬盤，加大工作集，減少對IO的需求。

主要優點：

· 隨機 I/O 吞吐量提高

· I/O 滯後時間縮短

· 事務吞吐量提高(減少io等待時間)

· 由于采用更大的混合緩沖池，讀取性能提高(SSD隨機读写能力强)

· 具有一種可利用現有和將來的低成本內存驅動器的緩存體系結構(因爲有SSD，可以減少对IO的投入)

Buffer Pool擴展詳細

SSD是作爲Buffer Pool的擴展，而不是磁盘存储的擴展，也就是说SSD是歸buffer pool管理器管，Buffer pool以在SSD上創建一個緩沖文件的方式存在，創建了一個多層的結構：

L1:內存，L2：SSD緩存文件。L2上面的數據都是幹淨的數據，L2目前看來只是爲讀提供緩存，不提供髒數據的緩存。從而加大了工作集，爲數據讀取提供良好的性能支持。

bubuko.com,布布扣

启用缓冲池擴展后，该功能会指定固态硬盘上缓冲池缓存文件的大小和文件路径。此文件是固態硬盤上的一個連續存儲範圍，是在 SQL Server 實例啓動期間靜態配置的。

ALTERSERVER CONFIGURATION SETBUFFERPOOL EXTENSION ON

(FILENAME=‘c:\sqlserver.PBE‘,size = 5GB)

bubuko.com,布布扣

bubuko.com,布布扣

bubuko.com,布布扣

只有在禁用了缓冲池擴展功能的情况下，才能修改此文件的配置參數。禁用缓冲池擴展后，将从注册表中删除所有相关的配置设置。SQL Server 实例关闭时，将会删除缓冲池擴展文件。

ALTERSERVER CONFIGURATION SETBUFFERPOOL EXTENSION OFF

最佳實踐

1. 缓冲池擴展大小最大可为 max_server_memory 值的 32 倍。我們建議物理內存 (max_server_memory) 的大小与缓冲池擴展的大小之比不应超过 1:16。介于 1:4 至 1:8 之間的比率是最佳的。

2. 在生产环境中实现之前，应彻底测试缓冲池擴展。處于生産過程中時，請避免對該文件進行配置更改或關閉該功能。因爲禁用該功能時會大大減小緩沖池大小，所以這些活動可能會對服務器性能産生負面影響。禁用时，不回收用于支持该功能的內存，直到重新启动 SQL Server 的實例。但是，如果重新啓用該功能，將重用內存而不必重新啓動實例。

Buffer pool 擴展相关信息

· sys.dm_os_buffer_pool_extension_configuration (Transact-SQL)

· sys.dm_os_buffer_descriptors (Transact-SQL)

XEvent	說明	參數
sqlserver.buffer_pool_extension_pages_written	在将页或页组从缓冲池逐出并写入缓冲池擴展文件时激发。	· number_page · first_page_id · first_page_offset · initiator_numa_node_id
sqlserver.buffer_pool_extension_pages_read	在将页从缓冲池擴展文件读取到缓冲池时激发。	· number_page · first_page_id · first_page_offset · initiator_numa_node_id
sqlserver.buffer_pool_extension_pages_evicted	在将页从缓冲池擴展文件中逐出时激发。	· number_page · first_page_id · first_page_offset · initiator_numa_node_id
sqlserver.buffer_pool_eviction_thresholds_recalculated	在計算逐出阈值時激發。	· warm_threshold · cold_threshold · pages_bypassed_eviction · eviction_bypass_reason · eviction_bypass_reason_description

參考

SQL Server 2014新特性探秘(2)-SSD Buffer Pool Extension

缓冲池擴展

ALTER SERVER CONFIGURATION (Transact-SQL)

SQL Server 2014新特性——Buffer Pool擴展,布布扣,bubuko.com

SQL Server 2014新特性——Buffer Pool擴展

標簽：des com http blog style class div img size log c

原文地址：http://www.cnblogs.com/Amaranthus/p/3695914.html

踩

(0)

贊

(0)

舉報

評論一句话評論（0）

分享檔案

更多>

2021年07月29日 (22)
2021年07月28日 (40)
2021年07月27日 (32)
2021年07月26日 (79)
2021年07月23日 (29)
2021年07月22日 (30)
2021年07月21日 (42)
2021年07月20日 (16)
2021年07月19日 (90)
2021年07月16日 (35)

周排行

更多

友情鏈接

蘭亭集智國之畫百度統計站長統計阿裏雲 chrome插件新版天聽網

關于我們 - 聯系我們 - 留言反饋

? 2014 mamicode.com 版權所有聯系我們:gaon5@hotmail.com

迷上了代碼！

"I acquaint the inhabitants of Liège of this, that they may understand what fate threatens them if they should assume a similar attitude. A raiding party of hostiles had passed near the fort, and had killed, with particular atrocity, a family of settlers. The man and his wife had been tortured to death, the baby had had its brains beaten out against the trunk of a tree, a very young child had been hung by the wrist tendons to two meat hooks on the walls of the ranch-house, and left there to die. One big boy had had his eyelids and lips and nose cut off, and had been staked down to the ground with his remains of a face lying over a red-ant hole. Only two had [Pg 196]managed to escape,—a child of ten, who had carried his tiny sister in his arms, twenty miles of ca?ons and hills, to the post. Every engine of the English Court was put in motion to prevent the Electoral Prince from coming. Oxford had an interview with Schutz, in which he repeated that it was his applying for the writ to the Lord Chancellor instead of to the queen that had done all the mischief; that her Majesty, had it not been for this untoward incident, would have invited the Prince to come over and spend the summer in England—forgetting, as Schutz observed, that the minute before he had assured him that the queen was too much afraid of seeing any of that family here. He advised Schutz—who could not be convinced that he had done anything irregular in his application, quoting numerous proofs to show that it was the accustomed mode of applying for writs—to avoid appearing again at Court; but Schutz, not seeming disposed to follow that advice, immediately received a positive order to the same effect from the queen through another channel. Schutz, therefore, lost no time in returning to Hanover to justify himself. At the same time, Lord Strafford was instructed to write from the Hague, blaming the conduct of Schutz in applying for the writ in the manner he did, as disrespectful to the queen; for, though strictly legal for an absent peer to make such application, the etiquette was that he should defer it till he could do it personally. Strafford ridiculed the idea of any movement being afoot in favour of the Pretender, and observed that, as to sending him out of the Duke of Lorraine's territory, it was not practicable, because the French king maintained that he had fulfilled the treaty, Lorraine not being any part of France. On the other hand, there were striking signs that the cause[17] of Hanover was in the ascendant. Men who watched the course of events decided accordingly. Marlborough, who so lately had been making court to the Pretender, now wrote from Antwerp, urging the House of Hanover to send over the prince without delay to England; that the state of the queen's health made prompt action necessary; and that the presence of the prince in London would secure the succession without risk, without expense, and without war, and was the likeliest measure of inducing France to abandon its design of assisting the Pretender. Shorty had been frantically trying to catch the Deacon's eye, and was making all manner of winks and warning gestures without avail, for the Deacon answered frankly: "Sure you do," Dodd said, and his voice began to rise. He went to the bed, walked along its length to the window, as he talked, never facing Albin. "You know how to make me feel just fine, no worries at all, no complications, just a nice, simple life. With nothing at all in it, Albin. Nothing at all." J. O., I mean it. "Good-bye, my Bluebell, farewell to you, "Cudn't spare one hand to fetch over fifteen—that's a valiant idea. Now d?an't go loitering; fetch out your cattle afore they're roast beef, git out the horses and all the stock—and souse them ricks wot ?un't burning yit." "Do you know my voice?" asked one of Wells's companions. HoME 亚洲春色欧美激情 ENTER NUMBET 0010www.3lim.com.cn
aab59.com.cn
baretos.org.cn
www.bjbcedu.com.cn
cmcsoft.cn
dgthef100.com.cn
gotodns.org.cn
haouschedul.cn
kricho.org.cn
www.wujianzhigp68.com.cn