Re: Support tid range scan in parallel?

Hi Steven

thanks for the review!

> I have two comments:
> 1. Does table_beginscan_parallel_tidrange() need an assert of relid,
> like what table_beginscan_parallel() did?
> Assert(RelationGetRelid(relation) == pscan->phs_relid);

In the v6 rebased patch, the assert has become:

Assert(RelFileLocatorEquals(relation->rd_locator, pscan->phs_locator));

rather than:

Assert(RelationGetRelid(relation) == pscan->phs_relid);

table_beginscan_parallel_tidrange() already has the proper assert line
similar to what table_beginscan_parallel() has.

> 2. The new field phs_numblock in ParallelBlockTableScanDescData
> structure has almost the same name as another field phs_nblocks. Would
> you consider changing it to another name, for example,
> phs_maxnumblocktoscan?

I actually had a similar thought too, phs_nblocks and phs_numblock are
very similar but are quite different. But I still left the name as phs_numblock
because I want to keep it consistent (kind of) with the 'numBlks' used in
heap_set_tidrange() in heapam.c. The comments besides their declaration
should be enough to describe their differences without causing confusion.

Best regards
Cary