Generate the statistics of a table after truncating it and then repopulate it

I don't know what CREATE STATISTICS does, but statistics for the optimizer are collected using the ANALZYE command when autovacuum is running - which is turned on by default.

Statistics are always collected for all columns, no need to turn it on specifically.

You can control the level of details collected for the statistics on a per-column basis using ALTER TABLE ... ALTER COLUMN column SET STATISTICS integer.

An index in PostgreSQL is always non-clustered, so I'd assume that the above index maps to a regular index on the QuestionId column.

Not sure about the INCLUDE part. I assume this is to support index only retrievals if that index is chosen by the optimizer. As PostgreSQL does not yet have an index-only retrieval, there is no equivalent technique there.

Time taken would depend on

• Row length
• Network Bandwidth
• Available resources on the source DB server
• And finally on data volume, as in number of rows

To put things in perspective - I recently did a similar migration. A table with 40 columns ( a mix on nvarchar and numeric) and 3 million rows of data took 35 minutes, where as another table with 7.5 million rows of data ( again a mix of nvarchar and numeric), but with 104 columns took more than 7 hours.

Conversely, a third table with 18 million rows of data, 6 columns, all numeric took 14 minutes. It is impossible to answer this question with Yes or No, with the information provided.

Raj