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Questions tagged [tombstone]

For questions about how the tombstone feature of a data-store or database works, or about how to implement such functionality.

A tombstone is a marker or flag used to indicate that a record has been deleted, as a substitute for actually deleting the record and immediately reclaiming the space it used. SQLServer, Microsoft Synchronization Services and Cassandra use tombstones.

Using tombstones can improve execution speed, at the cost of increased storage space.

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Do tombstones in Cassandra slow down queries even when not selected with where clause

If I have a single partition with 100'000 deleted rows in one cluster followed by a second cluster in the same partition with no deleted rows, will the performance of doing a SELECT * FROM example_table WHERE partition=that_partition AND…
AMVaddictionist
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Android 7.0: tombstone tells signal 6 (SIGABRT)

I have a large Android application including C/C++ libraries (via NDK/SWIG). At some point the app crashes and the tombstone file shows: signal 6 (SIGABRT), code -6 (SI_TKILL), fault addr -------- Abort message: 'Invalid address 0xbc9b306d passed…
René Heuven
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Can android System App (privileged) read or copy /data/tombstones

I've my app as system-priv and build along with my AOSP code. now my app needs to copy the tombstone folder which is under /data/tombstones to /sdcard. thanks in advance
Reddy
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Apache Cassandra: Explicit Read/Write consistencies required?

My company is using Cassandra (2.1.8), running on debian servers. Without setting a consistency on my queries/preparedStatements, I would sometimes get "null" back from a "SELECT * FROM table_name WHERE key = ?". After…
Nixxon
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Is it possible to avoid tombstone problems with Cassandra?

I am writing code for a CMS using Cassandra as the database system. One of the strength of the CMS is to pre-calculate all sorts of things using a backend computer that permanently runs against data that changes in the CMS. For example, the CMS…
Alexis Wilke
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where else tombstones are used in Cassandra other than SSTables?

Does Memtables and commit logs have Tombstones for marking deleted data? How does data deleted in Memtables are marked before flushing data?
Rathan
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Are the addresses in Android's tombstone file exactly matched to addresses in .so every time (even after reboot)?

When system crashed, it leaves a tombstone file in /data/tombstone. I found a bunch of addresses as below. #00 pc 00010a20 /system/lib/libc.so #01 pc 0000b332 /system/lib/libc.so #02 pc 0000ca62 /system/lib/bluez-plugin/audio.so #03 pc…
CodePoetry
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cleaning up cassandra tombstones from memtable

When I delete a row from cassandra and the data still lives in memtable (no SSTable has been created yet), it looks like that deleted row is never getting cleaned up in memtable since the tombstone cleanup is only done by compaction and compaction…
ppeddi
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GeoCoordinate System.FormatException

I have a viewmodel which contains a System.Device.Location.GeoCoordinate property which is marked as [DataMember] like so: [DataMember] public GeoCoordinate Location { get { return _location; } set { if (_location…
Igor Meszaros
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understand weird crash stack from android 13 device

I have a android 13 device, below crash happen sometimes during bootup! but the crash stack not show the crash libname, how should I know where is the crash code line? Cmdline: media.codec hw/android.hardware.media.omx@1.0-service pid: 1197, tid:…
lucky1928
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How to create tombstone records for tables with no primary key

I am using Confluent Oracle CDC to write a source connector. We have an old DB with no primary keys. I can get the key from the message and put it in as the message key for Kafka. This works fine for inserts and updates. But when I use…
Chris
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How does nodetool garbagecollect work on multiple data folders?

How nodetool garbagecollect removes the shadowed data from the SStable of data0 folder when the tombstone is present in the SStable of data1 folder.
Rohit Thakur
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" 'Tombstone' object has no attribute " error

I want to scrape first 200 replies (text, number of like, date...) from a tweet of April 2022 and save these data in a dataframe named 'replies1_apr_22.csv' but snscrape library for some reason is not working. Maybe the data I want to retrieve is…
Fabio Citti
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Is it possible that the tombstone be alive after gc_grace_seconds even after compaction in cassandra?

According to the documentation, In Cassandra, tombstones are removed during compaction. And it seems that there are some conditions to be removed well. after gc_grace_seconds Compaction include a sstable which contains tombstone and other sstables…
alexmoon
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How is Cassandra checking if row exists in other SSTables during minor compaction?

During minor compaction, to reclaim a row tombstone, how cassandra is checking whether the row exists in other sstables? It just checks partition key by bloom filter or checks row key? For example, there are 3 sstables: s1, s2 and s3. Assume s1 has…
user20621111
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