On Monday, June 9, 2014, Ian Barwick <i...@2ndquadrant.com> wrote: > > > On 09/06/14 14:47, David G Johnston wrote: > >> Ian Barwick wrote >> >>> Hi, >>> >>> The JDBC API provides the getGeneratedKeys() method as a way of >>> retrieving >>> primary key values without the need to explicitly specify the primary key >>> column(s). This is a widely-used feature, however the implementation has >>> significant >>> performance drawbacks. >>> >>> Currently this feature is implemented in the JDBC driver by appending >>> "RETURNING *" to the supplied statement. However this means all columns >>> of >>> affected rows will be returned to the client, which causes significant >>> performance problems, particularly on wide tables. To mitigate this, it >>> would >>> be desirable to enable the JDBC driver to request only the primary key >>> value(s). >>> >> >> ISTM that having a non-null returning clause variable when no returning is present in the command makes things more complicated and introduces unnecessary checks in the not uncommon case of multiple non-returning commands being issued in series.
returningList was able to be null and so should returningClause. Then if non-null first check for the easy column listing and then check for the more expensive PK lookup request. Then again the extra returning checks may just amount noise. David J.
