Re: Custom Scan APIs (Re: Custom Plan node)

Hi Kaigai-san,

2014-02-23 22:24 GMT+09:00 Kohei KaiGai <kaigai(at)kaigai(dot)gr(dot)jp>:
> (1) Interface to add alternative paths in addition to built-in join paths

I found that create_custom_path is not used at all in your patch.
I revised postgresql_fdw.c to use it like this.

...
/* Create join information which is stored as private information. */
memset(&jinfo, 0, sizeof(PgRemoteJoinInfo));
jinfo.fdw_server_oid = o_server_oid;
jinfo.fdw_user_oid = o_user_oid;
jinfo.relids = joinrel->relids;
jinfo.jointype = jointype;
jinfo.outer_rel = o_relinfo;
jinfo.inner_rel = i_relinfo;
jinfo.remote_conds = j_remote_conds;
jinfo.local_conds = j_local_conds;

/* OK, make a CustomScan node to run remote join */
cpath = create_customscan_path(root,
joinrel,
0, 0, 0, /* estimate later */
NIL,
required_outer,
"postgres-fdw",
0,
packPgRemoteJoinInfo(&jinfo));

estimate_remote_join_cost(root, cpath, &jinfo, sjinfo);

add_path(joinrel, &cpath->path);
...

This seems to work fine. Is this right approach? If so,this portion
would be a good example to replace local join with custom scan for
authors of custom scan providers. One thing I worry is the case that
you've intentionally avoided calling create_customscan_path.

--
Shigeru HANADA