Re: Reconstructing transaction content after the fact

2020-09-02 Thread Tom Lane
Alvaro Herrera writes: > On 2020-Sep-02, Tom Lane wrote: >> See VACUUM FREEZE. You couldn't hide connections immediately after >> insertion, but if the idea is to sanitize every so often, it'd help. > Starting with 9.4 which introduced the use of HEAP_XMIN_FROZEN > combination in infomask to rep

Re: Reconstructing transaction content after the fact

2020-09-02 Thread Alvaro Herrera
On 2020-Sep-02, Tom Lane wrote: > Lionel Bouton writes: > > Are these t_xmin values ever cleaned up (by VACUUM or another mechanism) > > ? If positive is there a way to configure the approximate time during > > which these values can be recovered ? > > See VACUUM FREEZE. You couldn't hide conn

Re: Reconstructing transaction content after the fact

2020-09-02 Thread Francisco Olarte
Lionel: On Wed, Sep 2, 2020 at 5:46 PM Lionel Bouton wrote: ... > The software uses a modern version of PostgreSQL (9.6 or later) and uses > a transaction to store a vote and the corresponding register entry in > two separate tables. ...> > There's already an obvious angle of attack to correlate

Re: Reconstructing transaction content after the fact

2020-09-02 Thread Tom Lane
Lionel Bouton writes: > Are txids in table file data indeed a means by which you can recover the > data written by a single transaction (assuming the txids don't overflow > the 32bit limit during the life of the cluster) ? They are. You could reduce the connections between different rows by writ