Re: [HACKERS] 32bit OID wrap around concerns

2015-03-02 Thread Tom Lane
Alvaro Herrera alvhe...@2ndquadrant.com writes: Qingqing Zhou wrote: Do we think above scenario is something we shall worry about? Especially for large databases. IMO in theory it sucks that toast values use the shared OID generator, though in practice I have never seen a problem due to

Re: [HACKERS] 32bit OID wrap around concerns

2015-03-02 Thread Qingqing Zhou
On Mon, Mar 2, 2015 at 12:38 PM, Tom Lane t...@sss.pgh.pa.us wrote: There is an issue if you do a dump and restore: the toast OIDs used in any one table will be consecutive after that, because we load all the data for each table sequentially. With these consecutive oids, the aggravated oid

[HACKERS] 32bit OID wrap around concerns

2015-03-02 Thread Qingqing Zhou
One scenario is to use an oid to identify a toast value. As the oid generation is mono increased within a database instance, it can gets wrap around after 2^32 generations. After that: 1. GetNewOidWithIndex() could gets unbounded performance as it needs to by pass already in use values of its own.

Re: [HACKERS] 32bit OID wrap around concerns

2015-03-02 Thread Alvaro Herrera
Qingqing Zhou wrote: One scenario is to use an oid to identify a toast value. As the oid generation is mono increased within a database instance, it can gets wrap around after 2^32 generations. After that: 1. GetNewOidWithIndex() could gets unbounded performance as it needs to by pass already