[MySQL] Change: faster retrieval of schema#1540
Merged
arikfr merged 1 commit intogetredash:masterfrom Jan 24, 2017
Merged
Conversation
Because `information_schema.tables` and `information_schema.columns` do not have indexes on them, when they get large, joining them becomes painful. We have a database with over 10k tables and more than 200k columns. The old query takes forever. The new query do not look at `information_schema.tables` at all. This works if your `information_schema.columns` table is in good shape in terms of data integrity (and it should be). Tested on MySQL 5.5, 5.6(Percona), 5.7(Percona). The schema has not changed since then.
arikfr
changed the title
Member
|
Merged. Thanks! |
dairyo
pushed a commit
to KiiCorp/redash
that referenced
this pull request
Mar 1, 2019
[MySQL] Change: faster retrieval of schema
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Because
information_schema.tablesandinformation_schema.columnsdo not have indexes on them, when they get large, joining them becomes painful. We have a database with over 10k tables and more than 200k columns. The old query takes forever.The new query do not look at
information_schema.tablesat all. This works if yourinformation_schema.columnstable is in good shape in terms of data integrity (and it should be).Tested on MySQL 5.5, 5.6(Percona), 5.7(Percona). The schema has not changed since then.