Re: Statistics Import and Export

Initially, I got things to work by having statistics import behave like COMMENTs, which meant that they were run immediately after the table/matview/index/constraint that created the pg_class/pg_attribute entries, but they could be suppressed with a --noX flag

Per previous comments, it was suggested by others that:

- having them in SECTION_NONE was a grave mistake
- Everything that could belong in SECTION_DATA should, and the rest should be in SECTION_POST_DATA

- This would almost certainly require the statistics import commands to be TOC objects (one object per pg_class entry, not one object per function call)

Turning them into TOC objects was a multi-phase process.

1. the TOC entries are generated with dependencies (the parent pg_class object as well as the potential unique/pk constraint in the case of indexes), but no statements are generated (in case the stats are filtered out or the parent object is filtered out). This TOC entry must have everything we'll need to later generate the function calls. So far, that information is the parent name, parent schema, and relkind of the parent object.

2. The TOC entries get sorted by dependencies, and additional dependencies are added which enforce the PRE/DATA/POST boundaries. This is where knowing the parent object's relkind is required, as that determines the DATA/POST section.

3. Now the TOC entry is able to stand on its own, and generate the statements if they survive the dump/restore filters. Most of the later versions of the patch were efforts to get the objects to fall into the right PRE/DATA/POST sections, and the central bug was that the dependencies passed into ARCHIVE_OPTS were incorrect, as the dependent object passed in was now the new TOC object, not the parent TOC object. Once that was resolved, things fell into place.