国产av日韩一区二区三区精品,成人性爱视频在线观看,国产,欧美,日韩,一区,www.成色av久久成人,2222eeee成人天堂

HBase "Raw" scans

php中文網(wǎng)
發(fā)布: 2016-06-07 16:26:19
原創(chuàng)
1884人瀏覽過(guò)

In HBase Scans (and by extension Gets) do not retrieve deleted cells or the tombstone markers that mark them as deleted. Sometimes is useful for trouble shooting (or backup - there will be a separate blog post about that soon) to see all c

In HBase Scans (and by extension Gets) do not retrieve deleted cells or the tombstone markers that mark them as deleted.
Sometimes is useful for trouble shooting (or backup - there will be a separate blog post about that soon) to see all cells including deleted cells and the tombstone markers.

HBASE-4536 introduces "raw" Scans (only available in HBase trunk - not the upcoming 0.92). In the Java client these are enabled by Scan.setRaw(true).

The HBase shell also supports this by adding RAW=>true to a scan.

Once raw mode is enabled the returned result contains not only the standard KeyValues, but also KeyValues for deleted cells and for tombstone markers (which are just special types of KeyValues, more on delete markers can be found here).

Here's an example of what it would look like in the shell:

hbase(main):001:0> scan 'x2', {RAW=>true, VERSIONS=>10}ROW                   COLUMN+CELL                                                r1                   column=f:c, timestamp=1323323611106, value=v3              r1                   column=f:c, timestamp=1323323609988, type=DeleteColumn     r1                   column=f:c, timestamp=1323323609988, value=v2              r1                   column=f:c, timestamp=1323323608554, value=v1              r2                   column=f:c, timestamp=1323323617759, value=v3              r2                   column=f:c, timestamp=1323323616226, value=v2              r2                   column=f:c, timestamp=1323323614496, value=v1             2 row(s) in 0.6380 seconds
登錄后復(fù)制

In this the above example values 'v2' and 'v1' for row key 'r1' have been deleted with a column delete marker.

hbase(main):005:0> scan 'x1', {RAW=>true, VERSIONS=>10}ROW                   COLUMN+CELL                                                r2                   column=f:, timestamp=1323323616226, type=DeleteFamily      r2                   column=f:c, timestamp=1323323617759, value=v3              r2                   column=f:c, timestamp=1323323616226, value=v2              r2                   column=f:c, timestamp=1323323614496, value=v1             2 row(s) in 0.0500 seconds
登錄后復(fù)制


Here 'v2' and 'v1' of row key 'r2' have been deleted with family delete marker.

Notice how the column marker is sorted in line with the cells it affects (it sorted after the cell for value 'v3'), but that the family marker is sorted before all cell of the affected row key.

The sort order was carefully designed to allow HBase to identify all cells affected by a delete marker in single forward scan through the store files(s).

最佳 Windows 性能的頂級(jí)免費(fèi)優(yōu)化軟件
最佳 Windows 性能的頂級(jí)免費(fèi)優(yōu)化軟件

每個(gè)人都需要一臺(tái)速度更快、更穩(wěn)定的 PC。隨著時(shí)間的推移,垃圾文件、舊注冊(cè)表數(shù)據(jù)和不必要的后臺(tái)進(jìn)程會(huì)占用資源并降低性能。幸運(yùn)的是,許多工具可以讓 Windows 保持平穩(wěn)運(yùn)行。

下載
來(lái)源:php中文網(wǎng)
本文內(nèi)容由網(wǎng)友自發(fā)貢獻(xiàn),版權(quán)歸原作者所有,本站不承擔(dān)相應(yīng)法律責(zé)任。如您發(fā)現(xiàn)有涉嫌抄襲侵權(quán)的內(nèi)容,請(qǐng)聯(lián)系admin@php.cn
最新問(wèn)題
開源免費(fèi)商場(chǎng)系統(tǒng)廣告
最新下載
更多>
網(wǎng)站特效
網(wǎng)站源碼
網(wǎng)站素材
前端模板
關(guān)于我們 免責(zé)申明 意見反饋 講師合作 廣告合作 最新更新
php中文網(wǎng):公益在線php培訓(xùn),幫助PHP學(xué)習(xí)者快速成長(zhǎng)!
關(guān)注服務(wù)號(hào) 技術(shù)交流群
PHP中文網(wǎng)訂閱號(hào)
每天精選資源文章推送
PHP中文網(wǎng)APP
隨時(shí)隨地碎片化學(xué)習(xí)
PHP中文網(wǎng)抖音號(hào)
發(fā)現(xiàn)有趣的

Copyright 2014-2025 http://m.miracleart.cn/ All Rights Reserved | php.cn | 湘ICP備2023035733號(hào)