What do you mean by page caching and block caching?

Answer 1

Page caching:

• If enables, page caching will only be used for anonymous users.

• If you enable page caching, the entire HTML of each page will be stored in the database. This significantly reduces the amount of queries needed.

• This automatically means that blocks will also get cached, disregarded their own cache settings.

• If Varnish is configured, this will also enable varnish caching

• The page cache max-age will be used (see below) for each page.

• You can check the "X-Drupal-Cache" HTTP header to check if this cache is HIT.

Block caching:

• If you enable block caching, without enabling page caching, the block cache settings will be used (for anonymous and authenticated).

• The defaults for most blocks is "don't cache" because that is the default for blocks who don't have their cache settings specifically declared.

• You can use block_cache_alter module to set this for each block.

• When it's block created by Views, you can set the cache settings for a block in Views.