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Is there a way to know the size of all KVs that are stored in a column family?

Eshkod
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2 Answers2

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  1. For API you can use: GetApproximateSizes().

  2. If you just want to check, you can check RocksDB log, which has per column family Compaction Stats, which SST file size for each level.

  3. It's not reporting column family size, but if you're interested in bytes written, there's a statistic reporting that: rocksdb.bytes.written, you can get statistic by setting statistics, like:

options.statistics = CreateDBStatistics()
Jay Zhuang
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  • Can you give an example of how to use `GetApproximateSizes()?` Specifically, if I want the size of the *entire* column, what do I use as a `Range`? – MyStackRunnethOver Sep 22 '21 at 18:53
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If you want to know the total size of all SST files under a column family, a better way is via GetIntProperty(). In your case, you want to pass-in kTotalSstFileSize.

bool ok = db_->GetIntProperty(DB::Properties::kTotalSstFilesSize, &sst_size);

If you only care about the latest version of the SST files, then you should use kTotalLiveSstFileSize instead.

keelar
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  • But how would this compare to `GetApproximateSizes` in terms of performance? Because with `GetApproximateSizes` you can decrease precision for a better performance, right? – luislhl Aug 10 '22 at 20:37