pingcap
Write more context in metadata (such as SQL Mode)
Feature Request
Is your feature request related to a problem? Please describe:
mydumper's metadata has some not so good design, for example, write an empty GTID: when not enable GTID.
and dumpling has diverged a little in https://github.com/pingcap/dumpling/pull/146 . so maybe we could record more context in metadata
Describe the feature you'd like:
SQL Mode (mainly ANSI_QUOTES) is needed to correctly parse dump files, so it should be written somewhere
for example
Started dump at: 2020-08-26 17:54:52
SHOW VARIABLES:
sql_mode: ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
SHOW MASTER STATUS:
Log: mysql-bin.000002
Pos: 194
GTID:09bec856-ba95-11ea-850a-58f2b4af5188:1-103
SHOW MASTER STATUS: /* AFTER CONNECTION POOL ESTABLISHED */
Log: mysql-bin.000002
Pos: 199
GTID:09bec856-ba95-11ea-850a-58f2b4af5188:1-103
Finished dump at: 2020-08-26 17:54:52
Describe alternatives you've considered:
currently DM will query SQL Mode from upstream, so it's OK not add this feature. But if user changes SQL Mode after dump it will fail.
and maybe dumpling could use a default context to dump SQLs.
Teachability, Documentation, Adoption, Optimization:
sql_mode is a global/session variable, it may changed easily. I think we can not truly tell what sql_mode is when the table created. so record the sql_mode for current snapshot is meaningless?
sql_mode take effect when dumpling read, not when table create.
dumpling would use all global variables as its session variables (if not configurated), and in dump process session variables are not changed by iteslf (and can't be changed from outside?). so I think it would represent dump file's context