polardbppas区别

Posted 2023-05-02

参考技术A PolarDB-X 2.0（以下简称PolarDB-X）与DRDS（DRDS也称为PolarDB-X 1.0）都是阿里云上的分布式数据库产品。看起来她们都是Share-Nothing的架构，用水平扩展来解决单机数据库瓶颈问题。很多同学因此会有疑惑，她们俩到底有什么样的区别？

DRDS，其本质是搭建在标准mysql（阿里云上的RDS For MySQL）上的分库分表中间件，具有很高的灵活性。 PolarDB-X是使用云原生技术的分布式数据库，具有一体化的数据库体验，其存储节点是经过了高度定制的MySQL，从而提供了大量中间件无法提供的能力（使用全局MVCC的强一致的分布式事务、私有RPC协议带来的性能提升、Follower上的一致性读能力等等）。

本文带大家从各个角度剖析下，PolarDB-X与DRDS的异同。

首先简单说下她们相似的地方：

她们都能基于Share-Nothing的架构，具备极强的水平扩展能力

她们都基于MySQL的生态体系，具有很高的MySQL兼容性

她们使用同样的SQL引擎，具备相似的SQL执行能力

她们均提供分布式事务、全局索引等常见中间件不具备的高阶能力

她们都在阿里巴巴内部广泛使用，历经多年双十一的考验，稳定可靠

接下来我们重点看下她们有哪些区别。

1.dash,crash的区别

1.dash,crash的区别
2.hold on,hold out,hold to作坚持的区别
3.send,detail,dispatch做派遣的区别
4.judge,justice作法官的区别

1.dash,crash的区别 dash主要指冲撞的过程，crash主要指冲撞的结果
2.hold on,hold out,hold to作坚持的区别 都只用坚持解释是语气强烈不一样，hold to表示丝毫不变，hold on表示没有改变，hold out尽量维持原状,语气强若可以看出来了吧，那就是由高到低为:hold to, hold on, hold out
3.send,detail,dispatch做派遣的区别 只丛派遣解释是：send有点敷衍了事，detail详细分说，dispatch表示分派，语气强若就非常明显了，由高到低是:detail,dispatch,send,
4.judge,justice作法官的区别 judge表示说了就算的最高级法官，justice表示普通法官 参考技术A 1.dash,crash的区别________________________________________________________________________________________________________________________________________
dash ： 1) v.t. To throw with violence or haste; to cause to strike violently or hastily; - often used with against. 2) v.t. To break, as by throwing or by collision; to shatter; to crust; to frustrate; to ruin. 3) v.t. To put to shame; to confound; to confuse; to abash; to depress. 4) v.t. To throw in or on in a rapid, careless manner; to mix, reduce, or adulterate, by throwing in something of an inferior quality; to overspread partially; to bespatter; to touch here and there; as, to dash wine with water; to dash paint upon a picture. 5) v.t. To form or sketch rapidly or carelessly; to execute rapidly, or with careless haste; - with off; as, to dash off a review or sermon. 6) v.t. To erase by a stroke; to strike out; knock out; - with out; as, to dash out a word. 7) v.i. To rust with violence; to move impetuously; to strike violently; as, the waves dash upon rocks. 8) n. Violent striking together of two bodies; collision; crash. 9) n. A sudden check; abashment; frustration; ruin; as, his hopes received a dash. 10) n. A slight admixture, infusion, or adulteration; a partial overspreading; as, wine with a dash of water; red with a dash of purple. 11) n. A rapid movement, esp. one of short duration; a quick stroke or blow; a sudden onset or rush; as, a bold dash at the enemy; a dash of rain. 12) n. Energy in style or action; animation; spirit. 13) n. A vain show; a blustering parade; a flourish; as, to make or cut a great dash. 14) n. A mark or line, in writing or printing, denoting a sudden break, stop, or transition in a sentence, or an abrupt change in its construction, a long or significant pause, or an unexpected or epigrammatic turn of sentiment. Dashes are also sometimes used instead of marks or parenthesis. 15) n. The sign of staccato, a small mark denoting that the note over which it is placed is to be performed in a short, distinct manner. 16) n. The line drawn through a figure in the thorough bass, as a direction to raise the interval a semitone. 17) n. A short, spirited effort or trial of speed upon a race course; - used in horse racing, when a single trial constitutes the race.#@ noun, verb \r\n noun\r\n sth done quickly\r\n 1 [sing.] a ~ (for sth) an act of going somewhere suddenly and/or quickly:\r\nWhen the doors opened, there was a mad dash for seats. * a 60-mile dash to safety * He jumped off the bus and made a dash for the nearest bar. * We waited for the police to leave then made a dash for it (= left quickly in order to escape).\r\n 2 [sing.] an act of doing sth quickly because you do not have enough time:\r\na last-minute dash to buy presents\r\n small amount\r\n 3 [C,?usually sing.] ~ (of sth) a small amount of sth that is added to sth else:\r\nAdd a dash of lemon juice. * The rug adds a dash of colour to the room. * The album is a mixture of rock and gospel, with a dash of jazz thrown in.\r\ncompare?SPLASH\r\n symbol\r\n 4 [C] the mark(-) used to separate parts of a sentence, often instead of a COLON or in pairs instead of BRACKETS\r\ncompare?HYPHEN\r\n race\r\n 5 [C,?usually sing.] (especially AmE) a race in which the competitors run very fast over a short distance\r\nSYN?SPRINT:\r\nthe 100-meter dash\r\n way of behaving\r\n 6 [U] (old-fashioned, approving) a way of behaving that combines style, enthusiasm and confidence:\r\nHe brought youthful energy, dash and charisma to the department.\r\n part of car\r\n 7 [C] (informal) = DASHBOARD\r\nsee also PEBBLE-DASH\r\n IDIOMS \r\n cut a dash (BrE) to look attractive in a particular set of clothes, especially in a way that makes other people notice you:\r\nHe cut quite a dash in his uniform.\r\n verb\r\n go quickly\r\n 1 [V] ? [usually +adv./prep.] to go somewhere very quickly:\r\nI must dash (= leave quickly), I''m late. * She dashed off to keep an appointment. * He dashed along the platform and jumped on the train.\r\n throw / beat\r\n 2 [+adv./prep.] to throw sth or make sth fall violently onto a hard surface; to beat against a surface:\r\n[VN] The boat was dashed repeatedly against the rocks. * [V] The waves were dashing against the harbour wall.\r\n IDIOMS \r\n dash sb''s hopes to destroy sb''s hopes by making what they were hoping for impossible:\r\nHopes of a peaceful settlement have been dashed.\r\n dash (it)! | dash it all! (old-fashioned, BrE) used to show that you are annoyed about sth\r\n?PHRASAL?VERBS?\r\n dash sth<->off to write or draw sth very quickly:\r\nI dashed off a note to my brother.\r\n

v [Date: 1200-1300; Origin: Probably from the sound of something breaking when hit] \n 1 [I always + adverb/preposition] to go or run somewhere very quickly: --Olive dashed into the room, grabbed her bag, and ran out again. \n 2 dash sb's hopes: to disappoint someone by telling them that what they want is not possible\n --Hopkins' hopes were dashed when his appeal was denied. \n 3 (I) must dash/(I) have to dash: BrE spoken used to tell someone that you must leave quickly\n --Anyway, I must dash - I said I'd meet Daniel at eight. \n 4 [I,T always + adverb/preposition] written to throw or push something violently against something, especially so that it breaks: dash sth against/on sth\n --The ship was dashed against the rocks.\n dash against\n --Waves were dashing against the sea wall. \n 5 dash it (all)!: BrE old-fashioned used to show that you are slightly annoyed or angry about something\n dash off phr v \n 1 to leave somewhere very quickly: --Harry dashed off before she had a chance to thank him. \n 2 dash sth <==> off: to write or draw something very quickly\n --She dashed off a quick letter. \ndash 2 n \n 1 small amount:\n 2 run quickly:\n 3 line:\n 4 sound:\n 5 car:\n 6 style:\n 7 cut a dash: \n 1 SMALL AMOUNT: [singular] \n a) a small amount of a substance that is added to something else\n dash of\n --Add salt, pepper and a dash of vinegar.\n b) a small amount of a quality that is added to something else\n dash of\n --Add a dash of romance to your life with a trip to Paris. \n 2 RUN QUICKLY: [C usually singular] an occasion when someone runs somewhere very quickly in order to get away from something or someone, or in order to reach them\n make a dash for sth\n --He made a dash for the door.\n --The prisoners made a dash for freedom.\n --It's pouring with rain - we'll have to make a dash for it .\n --When the alarm went there was a mad dash for the exit. \n 3 LINE: [C] a line [ - ] used in writing to separate two closely related parts of a sentence, as for example, in the sentence 'Go home - they're waiting for you.'\n --> hyphen \n 4 SOUND: [C] a long sound or flash of light used for sending messages in Morse code\n --> dot \n 5 CAR: [C] AmE a dashboard \n 6 STYLE: [U] old-fashioned style, energy, and courage in someone such as a soldier \n 7 cut a dash: old-fashioned to look very impressive and attractive in particular clothes\n --With her new image, she'll certainly cut a dash on her holiday cruise.
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crash: 1) v.t. To break in pieces violently; to dash together with noise and violence. 2) v.i. To make a loud, clattering sound, as of many things falling and breaking at once; to break in pieces with a harsh noise. 3) v.i. To break with violence and noise; as, the chimney in falling crashed through the roof. 4) n. A loud, sudden, confused sound, as of many things falling and breaking at once. 5) n. Ruin; failure; sudden breaking down, as of a business house or a commercial enterprise. 6) n. Coarse, heavy, narrow linen cloth, used esp. for towels. #@1. n. A sudden, usually drastic failure. Most often said of the system (q.v., sense 1), esp. of magnetic disk drives (the term originally described what happens when the air gap of a hard disk collapses). "Three lusers lost their files in last night''s disk crash." A disk crash that involves the read/write heads dropping onto the surface of the disks and scraping off the oxide may also be referred to as a `head crash'', whereas the term `system crash'' usually, though not always, implies that the operating system or other software was at fault.
2. v. To fail suddenly. "Has the system just crashed?" "Something crashed the OS!" See down. Also used transitively to indicate the cause of the crash (usually a person or a program, or both). "Those idiots playing SPACEWAR crashed the system." 3. vi. Sometimes said of people hitting the sack after a long hacking run; see gronk out. From Jargon Dictionary
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2.hold on,hold out,hold to作坚持的区别
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hold on:Seize;Continue;Not anything;Stop
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hold out:Support;Maintenance;Out;Uphold;Senegal;Maintenance;Stop;Stop;U.S. - > < detained;Claims
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hold to:Making;Uphold;Uphold;Our
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3.send,detail,dispatch做派遣的区别
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send: \r\n by mail / radio\r\n 1 ~ sth (to sb) | ~ sb sth to make sth go or be taken to a place, especially by post/mail, radio, etc:\r\n[VN] to send a letter / package / cheque / fax / e-mail * She sent the letter by airmail. * (BrE) to send sth by post * (AmE) to send sth by mail * A radio signal was sent to the spacecraft. * The CD player was faulty so we sent it back to the manufacturers. * [VN, VNN] Have you sent a postcard to your mother yet? * Have you sent your mother a postcard yet?\r\n message\r\n 2 to tell sb sth by sending them a message:\r\n[VN] My parents send their love. * What sort of message is that sending to young people? * [VNN] He sent me word to come. * [VN?(that)] She sent word (that) she could not come. * [V?to?inf] (formal) She sent to say that she was coming home.\r\n sb somewhere\r\n 3 to tell sb to go somewhere or to do sth; to arrange for sb to go somewhere: [VN, usually +adv./prep.] Ed couldn''t make it so they sent me instead. * She sent the kids to bed early. * to send sb to prison / boarding school * We are being sent on a training course next month. * [VN?to?inf] I''ve sent Tom to buy some milk.\r\n make sth move quickly\r\n 4 to make sth/sb move quickly or suddenly:\r\n[VN?-ing] Every step he took sent the pain shooting up his leg. * The punch sent him flying. * [VN?+adv./prep.] The report sent share prices down a further 8p.\r\n make sb react\r\n 5 ~ sb (to / into sth) to make sb behave or react in a particular way:\r\n[VN] Her music always sends me to sleep. * Her account of the visit sent us into fits of laughter. * [VN-ADJ] All the publicity nearly sent him crazy.\r\n IDIOMS \r\n send sb packing (informal) to tell sb firmly or rudely to go away:\r\nShe tried to interfere but I sent her packing.\r\nmore?at?COVENTRY, LOVE?n.\r\n?PHRASAL?VERBS?\r\n send away (to sb) (for sth) = SEND?OFF?(FOR?STH)\r\n send sb<->down (BrE)\r\n1 (informal) to send sb to prison\r\n2 (old-fashioned) to order a student to leave a university because of bad behaviour\r\n send for sb to ask or tell sb to come to you, especially in order to help you:\r\nSend for a doctor, quickly!\r\n send for sth to ask sb to bring or deliver sth to you:\r\nHis son found him and sent for help. * She sent for the latest sales figures.\r\n send sb forth (old-fashioned or literary) to send sb away from you to another place\r\n send forth sth (formal) to produce a sound, signal, etc. so that other people can hear it, receive it, etc:\r\nHe opened his mouth and sent forth a stream of noise.\r\n send sb<->in to order sb to go to a place to deal with a difficult situation:\r\nTroops were sent in to restore order.\r\n send sth<->in to send sth by post/mail to a place where it will be dealt with:\r\nHave you sent in your application yet?\r\n send off (for sth) | send away (to sb) (for sth) to write to sb and ask them to send you sth by post/mail:\r\nI''ve sent off for some books for my course.\r\n send sb<->off (BrE) (in a sports game) to order sb to leave the field because they have broken the rules of the game:\r\nBeckham was sent off for a foul in the second half.\r\nrelated?noun?SENDING-OFF\r\n send sth<->off to send sth to a place by post/mail:\r\nI''m sending the files off to my boss tomorrow.\r\n send sth<->on\r\n1 to send sth to a place so that it arrives before you get there:\r\nWe sent our furniture on by ship.\r\n2 to send a letter that has been sent to sb''s old address to their new address\r\nSYN?FORWARD:\r\nThey promised to send on our mail when we moved.\r\n3 to send sth from one place/person to another:\r\nThey arranged for the information to be sent on to us.\r\n send out for sth to ask a restaurant or shop/store to deliver food to you at home or at work:\r\nLet''s send out for a pizza.\r\n send sth<->out\r\n1 to send sth to a lot of different people or places:\r\nHave the invitations been sent out yet?\r\n2 to produce sth, such as light, a signal, sound, etc.\r\nSYN?EMIT:\r\nThe sun sends out light and heat.\r\n send sb/sth<->up (BrE, informal) to make people laugh at sb/sth by copying them/it in a funny way:\r\na TV programme that sends up politicians\r\nrelated?noun?SEND-UP\r\n

v past tense and past participle sent /sent/\n
\n 1 by post etc:\n 2 radio/computer etc:\n 3 person to place:\n 4 send (somebody) a message/signal:\n 5 send your love/regards/best wishes etc:\n 6 cause to move:\n 7 send somebody/something flying/sprawling/reeling etc:\n 8 affect:\n 9 send word:\n 10 send shivers/chills up (and down) your spine:\n 11 send somebody packing: Phrasal verbs\n send away for something\n send down\n send for somebody/something\n send something/somebody <==> in\n send off\n send something <==> on\n send out\n send something/somebody <==> up\n \n [Language: Old English; Origin: sendan]

\n 1 BY POST ETC: [T] to arrange for something to go or be taken to another place, especially by post\n --Lyn sent some pictures from the wedding.\n send sb sth\n --We sent Mom flowers for Mother's Day.\n --We sent her a letter of apology.\n send sth to sb/sth\n --I'll send a copy to you for your records.\n send sth back/up/over etc\n --He ordered coffee to be sent up.\n send sth by post/sea/air etc \n --Monday is the last day to send cards by post to arrive by Christmas.

\n 2 RADIO/COMPUTER ETC: [T] to make a message, electronic signal etc go somewhere, using radio equipment, computers etc\n send sb sth\n --I sent her an email yesterday.\n --Radio signals were sent into deep space.

\n 3 PERSON TO PLACE: a) [T] to ask or tell someone to go somewhere, especially so that they can do something for you there\n --The United Nations is sending troops.\n send sb to sth\n --A police officer was sent to Ryan's home.\n send sb back/away/over/home etc\n --Many of the refugees were sent back to Vietnam.\n --When Frank came, I told him I was ill and sent him away.\n --They sent me down to talk to Mr. Strachan.\n --Mr Ellison is here. Shall I send him in (=tell him to enter the room) ?\n send sb to do sth\n --The U.S. offered to send ships to help in the rescue operation.\n b) [T always + adverb/preposition] to arrange for someone to go to a place such as a school, prison, or hospital and spend some time there\n send sb to sth\n --I can't afford to send my kid to private school.\n --He was sent to prison for five years.\n send sb away/off\n --I was sent away to school at the age of six.\n send sb on sth\n --New employees are sent on an intensive training course.

\n 4 send (sb) a message/signal: if something that someone does or says sends a particular message, it has that meaning\n --Advertising sends the message that you have to be thin to be successful.

\n 5 send your love/regards/best wishes etc: spoken to ask someone to give your greetings, good wishes etc to someone else\n --Mother sends her love.

\n 6 CAUSE TO MOVE: [T always + adverb/preposition] to make something move from one place to another\n send sth through/to/over etc sth\n --The blaze sent smoke over much of the city.

\n 7 send sb/sth flying/sprawling/reeling etc: to make someone or something move quickly through the air or across something\n --The explosion sent glass flying everywhere.

\n 8 AFFECT: [T always + adverb/preposition] to make someone or something start to be in a particular state\n --His lectures always send me to sleep .\n send sb/sth into sth\n --The tail broke apart, sending the plane into a dive.

\n 9 send word: formal to tell someone something by sending them a letter or message\n send word (to sb) that/of sth\n --They sent word to the King of their arrival.

\n 10 send shivers/chills up (and down) your spine: to make you feel very frightened or excited\n --The eerie howl of the siren sent chills up her spine.

\n 11 send sb packing: informal to tell someone who is not wanted that they must leave at once\n --After his four years as governor, the voters sent him packing.\n send away for [send away for sth] phr v\n to send a letter to a company or organization asking them to send something to you\n --Send away for a free recipe booklet.\n send down phr v

\n 1 send sth <==> down: to make something lose value\n --The company's bad figures sent its share price down.

\n 2 send sb down: BrE informal to send someone to prison\n send somebody down for\n --He was sent down for possession of cocaine.

\n 3 be sent down: BrE old-fashioned to be told to leave a university because of bad behaviour\n send for / [send for sb/sth] phr v

\n 1 to ask or order that something be brought or sent to you, especially by writing a letter or by telephone: --Send for your free sample today!

\n 2 old-fashioned to ask or tell someone to come to you by sending them a message: --Charlie said he'd find a place to live and then send for me.\n --Get back into bed. I'll send for the doctor .\n --I've sent for help .\n send in [send sth/sb <==> in] phr v

\n 1 to send something, usually by post, to a place where it can be dealt with: --I sent in a few job applications last week.

\n 2 to send soldiers, police etc somewhere to deal with a difficult or dangerous situation: --British troops were sent in as part of the peace-keeping force.\n send off phr v

\n 1 send sth <==>off: to send something somewhere by post\n --I sent off the letter this morning.

\n 2 send off for sth: to send a letter to a company or organization asking them to post something to you\n --I sent off for a copy of the photograph.

\n 3 send sb<==> off: BrE to order a sports player to leave the field because they have broken the rules\n --One of Dundee's players was sent off for punching another player.\n send on [send sth <==> on] phr v

\n 1 especially BrE to send someone's letters or possessions to their new address from their old address: forward\n --My flatmate said she'd send on all my post.

\n 2 to send something that has been received to another place so that it can be dealt with: send something <==> on to\n --The data is then sent on to the Census Bureau.\n send out phr v

\n 1 send sth/sb <==> out: to make a person or a group of people or things go from one place to various other places\n --Information was sent out to interested students.\n --Search parties were sent out to look for survivors.

\n 2 send sth<==> out: to broadcast or produce a signal, light, sound etc\n --The ship is sending out an SOS signal.

\n 3 send out for sth: to ask a restaurant or food shop to deliver food to you at home or at work\n --We sent out for sandwiches.\n send up [send sth/sb <==> up] phr v

\n 1 to make something increas