Piotr Dulikowski 8c4cdfc2db select_statement: prepare paging for indexes on static columns ...

When performing a query on a table which is accelerated by a secondary
index, the paging state returned along with the query contains a
partition key and a clustering key of the secondary index table. The
logic wasn't prepared to handle the case of secondary indexes on static
columns - notably, it tried to put base table's clustering key columns
into the paging state which caused problems in other places.

This commit fixes the paging logic so that the PK and CK of a secondary
index table is calculated correctly. However, this solution has a major
drawback: because it is impossible to encode clustering key of the base
table in the paging state, partitions returned by queries accelerated by
secondary indexes on static columns will _not_ be split by paging. This
can be problematic in case there are large partitions in the base table.

The main advantage of this fix is that it is simple. Moreover, the
problem described above is not unique to static column indexes, but also
happens e.g. in case of some indexes on clustering columns (see case 2
of scylladb/scylla#7432). Fixing this issue will require a more
sophisticated solution and may affect more than only secondary indexes
on static columns, so this is left for a followup.

2022-12-06 11:21:16 +01:00

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