{"id":520,"date":"2018-05-02T16:15:59","date_gmt":"2018-05-02T16:15:59","guid":{"rendered":"https:\/\/www.gologica.com\/blog\/?p=520"},"modified":"2020-01-25T13:33:40","modified_gmt":"2020-01-25T13:33:40","slug":"greenplum-dba-interview-questions-and-answers","status":"publish","type":"post","link":"https:\/\/www.gologica.com\/elearning\/greenplum-dba-interview-questions-and-answers\/","title":{"rendered":"Greenplum DBA Interview Questions and Answers"},"content":{"rendered":"

What square measure Major variations Between Oracle and Greenplum?<\/strong><\/p>\n

Oracle is on-line database. Greenplum is MPP nature. Greenplum is shared nothing design. There square measure several alternative variations in terms of practicality and behaviour.<\/p>\n

A way to notice Errors \/ Fatal from Log Files?<\/strong><\/p>\n

Grep for ERRORS, FATAL, SIGSEGV in pglogs directory.<\/p>\n

What’s Vacuum And once ought to I Run This?<\/strong><\/p>\n

VACUUM reclaims storage occupied by deleted tuples. In traditional GPDB operation, tuples that square measure deleted or obsolete by Associate in nursing update don’t seem to be physically aloof from their table. They continue to be gift on disk till a VACUUM is finished. Therefore, it’s necessary to try and do VACUUM sporadically, particularly on frequently-updated table.<\/p>\n\n\n\n
<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\"Greenplum<\/a><\/p>\n

What’s Analyse and the way Frequency ought to I Run This?<\/strong><\/p>\n

ANALYZE collects statistics concerning the contents of tables within the info, and stores the ends up in the system table pgstatistic. Afterward, the question planner uses these statistics to assist verify the foremost economical execution plans for queries.<\/p>\n

It is an honest plan to run ANALYZE sporadically, or simply when creating major changes within the contents of a table. Correct statistics can facilitate the question set upper to settle on the foremost applicable question plan, and thereby improve the speed of question process. a standard strategy is to run VACUUM and ANALYZE once on a daily basis throughout a low-usage time of day.<\/p>\n

What’s Resource Queues?<\/strong><\/p>\n

Resource queues square measure accustomed manager Greenplum info work management. All user \/ queries are often prioritized mistreatment Resource queues.<\/p>\n

What’s Gptoolkit?<\/strong><\/p>\n

The gp_toolkit may be a info schema, that has several tables, views and functions to higher manage Greenplum info once sound unit is up. In 3.x earlier versions it had been stated as gp_jetpack.<\/p>\n

A way to Generate Ddl for a Table?<\/p>\n

Use pg_dump utility to get DDL.<\/p>\n

Example:<\/p>\n

pg_dump -t njonna.accounts -s -f ddl_accounts.sql<\/p>\n

Where:<\/p>\n

-f ddl_accounts.sql is computer file.<\/p>\n

-t njonna.accounts is table name with schema njonna.<\/p>\n

-s dump solely schema no information<\/p>\n

What square measure The Tools on the market In Greenplum to require Backup And Restores?<\/strong><\/p>\n

For non-parallel backups:<\/p>\n

Use postgres utililities (pg_dump, pg_dumpall for backup, and pg_restore for restore).<\/p>\n

Another helpful command for obtaining information out of info is that the COPY\u00a0 to .<\/p>\n

For parallel backups:<\/p>\n

gp_dump and gpcrondump for backups and gp_restore for restore method.<\/p>\n

What are Greenplum Performance Monitor and the way To Install?<\/strong><\/p>\n

It is a observation tool that collects statistics on system and question performance and builds historical knowledge.<\/p>\n

Once the shopper Connects will He connect with The Master Or phase Node?<\/strong><\/p>\n

Master<\/p>\n

Are you able to justify the method of information Migration From Oracle To Greenplum?<\/strong><\/p>\n

There square measure some ways. Simplest steps square measure Unload knowledge into csv files, produce tables in greenplum information equivalent to Oracle, produce external table, begin gpfdist inform to external table location, Load knowledge into greenplum. you’ll conjointly use gpload utility. Upload creates external table at runtime.<\/p>\n

That Command would you utilize To Backup A Database?<\/strong><\/p>\n

gp_dump,\u00a0 gpcrondump, pg_dump, pg_dumpall, copy<\/p>\n

However would approach question Tuning?<\/strong><\/p>\n

Look at the question arrange<\/p>\n

Look at the stats of the table\/tables within the question<\/p>\n

Look at the table distribution keys and joins within the question<\/p>\n

Look at the network performance<\/p>\n

Look at the resource queues<\/p>\n

Look at the interconnect performance<\/p>\n

Look at the be a part of order of tables within the question<\/p>\n

What would you are doing once A User Or Users square measure protestant That a selected question Is Running Slow?<\/strong><\/p>\n

Look at the question arrange<\/p>\n

Look at the stats of the table\/tables within the question<\/p>\n

Look at the table distribution keys and joins within the question<\/p>\n

look at the network performance<\/p>\n

Look at the resource queues<\/p>\n

Look at the interconnect performance<\/p>\n

Look at the be a part of order of tables within the question<\/p>\n

What would you are doing to assemble Statistics within the Database? Moreover As Reclaim The Space?<\/p>\n

A VACUUM FULL , CTAS : A VACUUM FULL can reclaim all terminated row area, however may be a terribly costly operation and will take associate intolerably long term to end on giant, distributed Greenplum information tables. If you are doing get into a scenario wherever the free area map has overflowed, it should be a lot of timely to recreate the table with a produce TABLE AS statement and drop the previous table. A VACUUM FULL isn’t suggested in Greenplum information.<\/p>\n

However Would You Implement Compression And justify attainable The Compression Types?<\/strong><\/p>\n

There square measure 2 varieties of in-database compression on the market within the Greenplum information for append-only tables:<\/p>\n

Table-level compression is applied to a complete table.<\/p>\n

Column-level compression is applied to a particular column. you’ll apply totally column-level compression algorithms to different columns.<\/p>\n\n\n\n
<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\"Greenplum<\/a><\/p>\n

If you put together Your With Master And phase Nodes, wherever Would the info Reside?<\/strong><\/p>\n

Segment nodes.<\/p>\n

Once A User Submits a question, wherever will It Run In Master Or phase Nodes?<\/strong><\/p>\n

Segment nodes<\/p>\n

What’s the placement Of Pg_hba\/logfile\/master_data_directory?<\/strong><\/p>\n

cd $MASTER_DATA_DIRECTORY \u2013 Master directory.<\/p>\n

pg_hba.conf and postgres.conf location and different GPDB internal directories.<\/p>\n

cd $MASTER_DATA_DIRECTORY\/pg_logs \u2014 Master information logfiles location.<\/p>\n","protected":false},"excerpt":{"rendered":"

What square measure Major variations Between Oracle and Greenplum? Oracle is on-line database. Greenplum is MPP nature. Greenplum is shared …<\/p>\n","protected":false},"author":1,"featured_media":2180,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"pmpro_default_level":"","footnotes":""},"categories":[43],"tags":[],"coauthors":[182],"class_list":["post-520","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-big-data-and-hadoop-interview-questions-and-answers","pmpro-has-access","user-has-not-earned"],"yoast_head":"\nGreenplum DBA Interview Questions and Answers - GoLogica<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.gologica.com\/elearning\/greenplum-dba-interview-questions-and-answers\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Greenplum DBA Interview Questions and Answers - GoLogica\" \/>\n<meta property=\"og:description\" content=\"What square measure Major variations Between Oracle and Greenplum? 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