Re: open database on read only file system

Thanks Scott. Do you know if there is any way to support read-only FS? for instance patch or extension.

I noticed the error is from file md.c

========

/*

 * mdopen() -- Open the specified relation.

 *

 * Note we only open the first segment, when there are multiple segments.

 *

 * If first segment is not present, either ereport or return NULL according

 * to "behavior".  We treat EXTENSION_CREATE the same as EXTENSION_FAIL;

 * EXTENSION_CREATE means it's OK to extend an existing relation, not to

 * invent one out of whole cloth.

 */

static MdfdVec *

mdopen(SMgrRelation reln, ForkNumber forknum, int behavior)

========

so I changed the file open mode from O_RDWR to O_RDONLY

fd = PathNameOpenFile(path, O_RDONLY | PG_BINARY, 0600);

and it works. I can open the user database, and query table now. Do you think if there is any potential problem of this change?

I just need to open database on read-only file system, and no need any changes on the cluster. thanks