Literally just encountered this exact same thing. I couldn't find anything in the official docs related to this but there is at least this blog that explains it: http://www.jsravn.com/2015/05/13/cassandra-tombstones-collections.html and this entry in ScyllaDB's documentation: http://www.scylladb.com/kb/sstable-interpretation/ Can confirm what Tyler mentioned, updating a single element does not cause a tombstone.
On 25 May 2016 at 15:37, Tyler Hobbs <ty...@datastax.com> wrote: > If you replace an entire collection, whether it's a map, set, or list, a > range tombstone will be inserted followed by the new collection. If you > only update a single element, no tombstones are generated. > > On Wed, May 25, 2016 at 9:48 AM, Matthias Niehoff < > matthias.nieh...@codecentric.de> wrote: > >> Hi, >> >> we have a table with a Map Field. We do not delete anything in this >> table, but to updates on the values including the Map Field (most of the >> time a new value for an existing key, Rarely adding new keys). We now >> encounter a huge amount of thumbstones for this Table. >> >> We used sstable2json to take a look into the sstables: >> >> >> {"key": "Betty_StoreCatalogLines:7", >> >> "cells": [["276-1-6MPQ0RI-276110031802001001:","",1463820040628001], >> >> ["276-1-6MPQ0RI-276110031802001001:last_modified","2016-05-21 >> 08:40Z",1463820040628001], >> >> >> ["276-1-6MPQ0RI-276110031802001001:last_modified_by_source:_","276-1-6MPQ0RI-276110031802001001:last_modified_by_source:!",1463040069753999,"t",1463040069], >> >> >> ["276-1-6MPQ0RI-276110031802001001:last_modified_by_source:_","276-1-6MPQ0RI-276110031802001001:last_modified_by_source:!",1463120708590002,"t",1463120708], >> >> >> ["276-1-6MPQ0RI-276110031802001001:last_modified_by_source:_","276-1-6MPQ0RI-276110031802001001:last_modified_by_source:!",1463145700735007,"t",1463145700], >> >> >> ["276-1-6MPQ0RI-276110031802001001:last_modified_by_source:_","276-1-6MPQ0RI-276110031802001001:last_modified_by_source:!",1463157430862000,"t",1463157430], >> >> >> [„276-1-6MPQ0RI-276110031802001001:last_modified_by_source:_“,“276-1-6MPQ0RI-276110031802001001:last_modified_by_source:!“,1463164595291002,"t",1463164595], >> >> . . . >> >> >> ["276-1-6MPQ0RI-276110031802001001:last_modified_by_source:_","276-1-6MPQ0RI-276110031802001001:last_modified_by_source:!",1463820040628000,"t",1463820040], >> >> >> ["276-1-6MPQ0RI-276110031802001001:last_modified_by_source:62657474795f73746f72655f636174616c6f675f6c696e6573","00000154d265c6b0",1463820040628001], >> >> >> [„276-1-6MPQ0RI-276110031802001001:payload“,"{\"payload\":{\"Article >> Id\":\"276110031802001001\",\"Row Id\":\"1-6MPQ0RI\",\"Article >> #\":\"31802001001\",\"Quote Item Id\":\"1-6MPWPVC\",\"Country >> Code\":\"276\"}}",1463820040628001] >> >> >> >> Looking at the SStables it seem like every update of a value in a Map >> breaks down to a delete and insert in the corresponding SSTable (see all >> the thumbstone flags „t“ in the extract of sstable2json above). >> >> We are using Cassandra 2.2.5. >> >> Can you confirm this behavior? >> >> Thanks! >> -- >> Matthias Niehoff | IT-Consultant | Agile Software Factory | Consulting >> codecentric AG | Zeppelinstr 2 | 76185 Karlsruhe | Deutschland >> tel: +49 (0) 721.9595-681 | fax: +49 (0) 721.9595-666 | mobil: +49 (0) >> 172.1702676 >> www.codecentric.de | blog.codecentric.de | www.meettheexperts.de | >> www.more4fi.de >> >> Sitz der Gesellschaft: Solingen | HRB 25917| Amtsgericht Wuppertal >> Vorstand: Michael Hochgürtel . Mirko Novakovic . Rainer Vehns >> Aufsichtsrat: Patric Fedlmeier (Vorsitzender) . Klaus Jäger . Jürgen >> Schütz >> >> Diese E-Mail einschließlich evtl. beigefügter Dateien enthält >> vertrauliche und/oder rechtlich geschützte Informationen. Wenn Sie nicht >> der richtige Adressat sind oder diese E-Mail irrtümlich erhalten haben, >> informieren Sie bitte sofort den Absender und löschen Sie diese E-Mail und >> evtl. beigefügter Dateien umgehend. Das unerlaubte Kopieren, Nutzen oder >> Öffnen evtl. beigefügter Dateien sowie die unbefugte Weitergabe dieser >> E-Mail ist nicht gestattet >> > > > > -- > Tyler Hobbs > DataStax <http://datastax.com/> > -- Kurt Greaves k...@instaclustr.com www.instaclustr.com