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Postgres Metadata, Nullable

[This topic is migrated from our old forums. The original author name has been removed]

Dear Sirs, I am working with "remote" (through Internet and VPN) Postgres servers, and I noticed that DBVis displays table data from Postgres databases much slower than from e.g. SQL server. I examined this (using JDBC driver sources) and found that DBVis queries the meta data of the result set, and calls ResultSetMetaData.isNullable() for each column. Then, unfortunately, the driver sends a query to the server for each column to find out whether it's nullable. Thus this feature request: DBVis should not call isNullable(), or postpone the call until that information is needed, or cache that infomation. Kind regards, Matthias Bergk

[This reply is migrated from our old forums.]

Re: Postgres Metadata, Nullable
Matthias, Thanks for your post. I'll register an RFE for this. It might also be a good idea sending the very same request to the JDBC group at PostgreSQL as this is certainly interesting for them to look into. Regards Roger
[This reply is migrated from our old forums. The original author name has been removed]

Re: Postgres Metadata, Nullable
Roger, I took the matter a little further and found that the function ResultSetMetaData.isAutoIncrement() is also concerned. After changing the driver so that both isNullable() and isAutoIncrement() return fixed values (columnNullableUnknown and false resp.) the perceived performance gain is tremendous. Fortunately, the colum information of tables and views still show correct information. Regards, Matthias
[This reply is migrated from our old forums. The original author name has been removed]

Re: Postgres Metadata, Nullable
For other people who might read this post, the lastest postgreSQL 9.1 driver fixes the slow retrieval of columns.