Too many tombstones in schema_columns from creating too many CFs

When creating lots of columnfamilies (about 200) the system.schema_columns gets filled with tombstones and therefore prevents clients using the binary protocol of connecting.

Clients already connected continue normal operation (reading and inserting).

Log messages are:

For the first tries (sorry for the lack of precision):

ERROR [main] 2015-04-22 00:01:38,527 SliceQueryFilter.java (line 200) Scanned over 100000 tombstones in system.schema_columns; query aborted (see tombstone_failure_threshold)

For each client that tries to connect but fails with timeout:

WARN [ReadStage:35] 2015-04-27 15:40:10,600 SliceQueryFilter.java (line 231) Read 395 live and 1217 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147283441 columns was requested, slices=[-]

WARN [ReadStage:40] 2015-04-27 15:40:10,609 SliceQueryFilter.java (line 231) Read 395 live and 1217 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147283441 columns was requested, slices=[-]

WARN [ReadStage:61] 2015-04-27 15:40:10,670 SliceQueryFilter.java (line 231) Read 395 live and 1217 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147283441 columns was requested, slices=[-]

WARN [ReadStage:51] 2015-04-27 15:40:10,670 SliceQueryFilter.java (line 231) Read 395 live and 1217 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147283441 columns was requested, slices=[-]

WARN [ReadStage:55] 2015-04-27 15:40:10,675 SliceQueryFilter.java (line 231) Read 395 live and 1217 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147283441 columns was requested, slices=[-]

WARN [ReadStage:35] 2015-04-27 15:40:10,707 SliceQueryFilter.java (line 231) Read 1146 live and 3534 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147282894 columns was requested, slices=[-]

WARN [ReadStage:40] 2015-04-27 15:40:10,708 SliceQueryFilter.java (line 231) Read 1146 live and 3534 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147282894 columns was requested, slices=[-]

WARN [ReadStage:43] 2015-04-27 15:40:10,715 SliceQueryFilter.java (line 231) Read 395 live and 1217 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147283441 columns was requested, slices=[-]

WARN [ReadStage:51] 2015-04-27 15:40:10,736 SliceQueryFilter.java (line 231) Read 1146 live and 3534 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147282894 columns was requested, slices=[-]

WARN [ReadStage:61] 2015-04-27 15:40:10,736 SliceQueryFilter.java (line 231) Read 1146 live and 3534 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147282894 columns was requested, slices=[-]

WARN [ReadStage:35] 2015-04-27 15:40:10,750 SliceQueryFilter.java (line 231) Read 864 live and 2664 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147281748 columns was requested, slices=[-]

WARN [ReadStage:40] 2015-04-27 15:40:10,751 SliceQueryFilter.java (line 231) Read 864 live and 2664 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147281748 columns was requested, slices=[-]

WARN [ReadStage:55] 2015-04-27 15:40:10,759 SliceQueryFilter.java (line 231) Read 1146 live and 3534 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147282894 columns was requested, slices=[-]

WARN [ReadStage:51] 2015-04-27 15:40:10,821 SliceQueryFilter.java (line 231) Read 864 live and 2664 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147281748 columns was requested, slices=[-]

WARN [ReadStage:61] 2015-04-27 15:40:10,822 SliceQueryFilter.java (line 231) Read 864 live and 2664 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147281748 columns was requested, slices=[-]

WARN [ReadStage:43] 2015-04-27 15:40:10,827 SliceQueryFilter.java (line 231) Read 1146 live and 3534 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147282894 columns was requested, slices=[-]

WARN [ReadStage:55] 2015-04-27 15:40:10,838 SliceQueryFilter.java (line 231) Read 864 live and 2664 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147281748 columns was requested, slices=[-]

WARN [ReadStage:62] 2015-04-27 15:40:10,846 SliceQueryFilter.java (line 231) Read 395 live and 1217 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147283441 columns was requested, slices=[-]

WARN [ReadStage:43] 2015-04-27 15:40:10,862 SliceQueryFilter.java (line 231) Read 864 live and 2664 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147281748 columns was requested, slices=[-]

WARN [ReadStage:62] 2015-04-27 15:40:10,898 SliceQueryFilter.java (line 231) Read 1146 live and 3534 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147282894 columns was requested, slices=[-]

WARN [ReadStage:62] 2015-04-27 15:40:10,970 SliceQueryFilter.java (line 231) Read 864 live and 2664 tombstoned cells in system.schema_columns (see tombstone_warn_threshold). 2147281748 columns was requested, slices=[-]

This happens independently of values in:
tombstone_warn_threshold, tombstone_failure_threshold

Thrift doesn't seem to be vulnerable to this, as cqlsh connects every time.

Binary protocol tested with Java (and Clojure), Python, C++ all fail to connect.

Included in attachment are a cql script to replicate (with 500 CFs) and a sstablemetadata output of a system.schema_columns sstable before (clean cluster) and after importing the schema.