Re: recovering from "found xmin ... from before relfrozenxid ..."

[Asim Praveen]

Hi Ashutosh

I stumbled upon this thread today, went through your patch and it looks good.  
A minor suggestion in sanity_check_relation():

        if (rel->rd_rel->relam != HEAP_TABLE_AM_OID)
                ereport(ERROR,
                                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                                 errmsg("only heap AM is supported")));

Instead of checking the access method OID, it seems better to check the handler 
OID like so:

        if (rel->rd_amhandler != HEAP_TABLE_AM_HANDLER_OID)

The reason is current version of sanity_check_relation() would emit error for 
the following case even when the table structure is actually heap.

        create access method myam type table handler heap_tableam_handler;
        create table mytable (…) using myam;

Asim