{"action":"created","issue":{"url":"https://api.github.com/repos/greenplum-db/gpdb/issues/4258","repository_url":"https://api.github.com/repos/greenplum-db/gpdb","labels_url":"https://api.github.com/repos/greenplum-db/gpdb/issues/4258/labels{/name}","comments_url":"https://api.github.com/repos/greenplum-db/gpdb/issues/4258/comments","events_url":"https://api.github.com/repos/greenplum-db/gpdb/issues/4258/events","html_url":"https://github.com/greenplum-db/gpdb/pull/4258","id":286465632,"number":4258,"title":"Enabled index scan for append-only tables","user":{"login":"jianlirong","id":519124,"avatar_url":"https://avatars0.githubusercontent.com/u/519124?v=4","gravatar_id":"","url":"https://api.github.com/users/jianlirong","html_url":"https://github.com/jianlirong","followers_url":"https://api.github.com/users/jianlirong/followers","following_url":"https://api.github.com/users/jianlirong/following{/other_user}","gists_url":"https://api.github.com/users/jianlirong/gists{/gist_id}","starred_url":"https://api.github.com/users/jianlirong/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/jianlirong/subscriptions","organizations_url":"https://api.github.com/users/jianlirong/orgs","repos_url":"https://api.github.com/users/jianlirong/repos","events_url":"https://api.github.com/users/jianlirong/events{/privacy}","received_events_url":"https://api.github.com/users/jianlirong/received_events","type":"User","site_admin":false},"labels":[],"state":"closed","locked":false,"assignee":{"login":"vraghavan78","id":12649877,"avatar_url":"https://avatars1.githubusercontent.com/u/12649877?v=4","gravatar_id":"","url":"https://api.github.com/users/vraghavan78","html_url":"https://github.com/vraghavan78","followers_url":"https://api.github.com/users/vraghavan78/followers","following_url":"https://api.github.com/users/vraghavan78/following{/other_user}","gists_url":"https://api.github.com/users/vraghavan78/gists{/gist_id}","starred_url":"https://api.github.com/users/vraghavan78/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/vraghavan78/subscriptions","organizations_url":"https://api.github.com/users/vraghavan78/orgs","repos_url":"https://api.github.com/users/vraghavan78/repos","events_url":"https://api.github.com/users/vraghavan78/events{/privacy}","received_events_url":"https://api.github.com/users/vraghavan78/received_events","type":"User","site_admin":false},"assignees":[{"login":"vraghavan78","id":12649877,"avatar_url":"https://avatars1.githubusercontent.com/u/12649877?v=4","gravatar_id":"","url":"https://api.github.com/users/vraghavan78","html_url":"https://github.com/vraghavan78","followers_url":"https://api.github.com/users/vraghavan78/followers","following_url":"https://api.github.com/users/vraghavan78/following{/other_user}","gists_url":"https://api.github.com/users/vraghavan78/gists{/gist_id}","starred_url":"https://api.github.com/users/vraghavan78/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/vraghavan78/subscriptions","organizations_url":"https://api.github.com/users/vraghavan78/orgs","repos_url":"https://api.github.com/users/vraghavan78/repos","events_url":"https://api.github.com/users/vraghavan78/events{/privacy}","received_events_url":"https://api.github.com/users/vraghavan78/received_events","type":"User","site_admin":false}],"milestone":null,"comments":9,"created_at":"2018-01-06T07:05:00Z","updated_at":"2018-04-17T20:32:58Z","closed_at":"2018-04-17T20:20:00Z","author_association":"CONTRIBUTOR","pull_request":{"url":"https://api.github.com/repos/greenplum-db/gpdb/pulls/4258","html_url":"https://github.com/greenplum-db/gpdb/pull/4258","diff_url":"https://github.com/greenplum-db/gpdb/pull/4258.diff","patch_url":"https://github.com/greenplum-db/gpdb/pull/4258.patch"},"body":"As the title suggested, this commit enables the planner to generate index scan plans for append-only (including row-oriented and column-oriented) tables.\r\n\r\nA little bit about the background of this commit. In our company, HashData Inc., we are using append-only tables (especially column-oriented) aggressively. This is because we are using object storage services, such as AWS S3, Aliyun OSS, QingCloud QingStor and etc., as the underlying storage layer, and the objects (files) provided by most of object storage systems are immutable. Using append-only tables as the default table format is a more natural choice. Even using append-only tables, we still want to provide full functionalities as those provided by heap tables. That's why we want to enable index scan for append-only tables. Actually, even for GPDB, in many usage cases of append-only tables, index scan plans are 100~1000 times faster than sequence scan plans, especially for those queries like \"ORDER BY key LIMIT 10\" with a btree index built on the \"key\" column.\r\n\r\nThere are some remaining issues: (1) this commit only enabled the legacy planner to generate index scan plans for append-only tables; we still need to update the code of ORCA to enable ORCA to generate index scan plans for append-only tables. Since I am not quite familiar with ORCA, that task is far beyond my capability. (2) Even for the legacy planner, the implementation of this commit just works. There is still much room for improvement.\r\n\r\n\r\n"},"comment":{"url":"https://api.github.com/repos/greenplum-db/gpdb/issues/comments/382132310","html_url":"https://github.com/greenplum-db/gpdb/pull/4258#issuecomment-382132310","issue_url":"https://api.github.com/repos/greenplum-db/gpdb/issues/4258","id":382132310,"user":{"login":"ashwinstar","id":11396815,"avatar_url":"https://avatars2.githubusercontent.com/u/11396815?v=4","gravatar_id":"","url":"https://api.github.com/users/ashwinstar","html_url":"https://github.com/ashwinstar","followers_url":"https://api.github.com/users/ashwinstar/followers","following_url":"https://api.github.com/users/ashwinstar/following{/other_user}","gists_url":"https://api.github.com/users/ashwinstar/gists{/gist_id}","starred_url":"https://api.github.com/users/ashwinstar/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/ashwinstar/subscriptions","organizations_url":"https://api.github.com/users/ashwinstar/orgs","repos_url":"https://api.github.com/users/ashwinstar/repos","events_url":"https://api.github.com/users/ashwinstar/events{/privacy}","received_events_url":"https://api.github.com/users/ashwinstar/received_events","type":"User","site_admin":false},"created_at":"2018-04-17T20:32:58Z","updated_at":"2018-04-17T20:32:58Z","author_association":"MEMBER","body":"On Tue, Apr 17, 2018 at 1:20 PM, Dhanashree Kashid <notifications@github.com\n> wrote:\n\n> We have a created a story in our backlog to track this. Hence closing the\n> PR.\n>\nNot in favor to track this internally, instead better to leave it open here\nin GitHub. Its okay if we are not able to get to it but shouldn't be closed.\n"}}
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