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/>
