huaxingao commented on pull request #30154:
URL: https://github.com/apache/spark/pull/30154#issuecomment-721542287
> when users specify some table properties, JDBC V2 should fail if the
underlying database can't support the properties.
I agree JDBC V2 should fail if the underlying database can't support the
properties. However, I feel it's hard to come up with a complete list of the
supported properties for each of the databases. It is easy to have a complete
list of the supported properties for MySQL because in CREATE TABLE syntax, it
explicitly lists the table_options:
```
table_option: {
AUTO_INCREMENT [=] value
| AVG_ROW_LENGTH [=] value
| [DEFAULT] CHARACTER SET [=] charset_name
| CHECKSUM [=] {0 | 1}
| [DEFAULT] COLLATE [=] collation_name
| COMMENT [=] 'string'
| COMPRESSION [=] {'ZLIB' | 'LZ4' | 'NONE'}
| CONNECTION [=] 'connect_string'
| {DATA | INDEX} DIRECTORY [=] 'absolute path to directory'
| DELAY_KEY_WRITE [=] {0 | 1}
| ENCRYPTION [=] {'Y' | 'N'}
| ENGINE [=] engine_name
| ENGINE_ATTRIBUTE [=] 'string'
| INSERT_METHOD [=] { NO | FIRST | LAST }
| KEY_BLOCK_SIZE [=] value
| MAX_ROWS [=] value
| MIN_ROWS [=] value
| PACK_KEYS [=] {0 | 1 | DEFAULT}
| PASSWORD [=] 'string'
| ROW_FORMAT [=] {DEFAULT | DYNAMIC | FIXED | COMPRESSED | REDUNDANT |
COMPACT}
| SECONDARY_ENGINE_ATTRIBUTE [=] 'string'
| STATS_AUTO_RECALC [=] {DEFAULT | 0 | 1}
| STATS_PERSISTENT [=] {DEFAULT | 0 | 1}
| STATS_SAMPLE_PAGES [=] value
| TABLESPACE tablespace_name [STORAGE {DISK | MEMORY}]
| UNION [=] (tbl_name[,tbl_name]...)
}
```
but other databases don't have explicitly defined table_options. I am not
sure which of the properties should be considered as valid table properties.
For example, for postgresql,
https://www.postgresql.org/docs/9.1/sql-createtable.html, should we treat
`TABLESPACE tablespace` or `CONSTRAINT constraint_name` as valid table
properties? I feel it might be better to send properties to underlying
databases and let databases decide whether to fail the CREATE TALBE or not,
than trying to have a complete list of the supported properties on Spark side.
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