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  1. Cassandra
  2. CASSANDRA-14570

Improper default value of cdc_total_space_in_mb

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    Details

    • Type: Bug
    • Status: Patch Available
    • Priority: Low
    • Resolution: Unresolved
    • Fix Version/s: None
    • Component/s: Local/Config
    • Labels:
    • Severity:
      Low

      Description

      The code for calculating cdc_total_space_in_mb in DatabaseDescriptor.java does not reflect the latest architecture introduced by CASSANDRA-12148.

      In short, cdc_total_space_in_mb should be equal or greater than commitlog_total_space_in_mb; otherwise, the writes will fail when on-disk commit logs size reaches the value of cdc_total_space_in_mb. For example, If cdc_total_space_in_mb is 4096 and commitlog_total_space_in_mb is 8192, when we enabled the cdc_enabled flag (even if we didn't enable cdc=true on any table), when total size of commit logs reaches 4096 MB, there is the same of amount of hard links in cdc_raw directory, that is, 4096 MB of cdc logs. Then, if a table has cdc=true, the writes will fail in that table because the CommitLogSegmentManagerCDC will be unable to process new CDC segments. (See allocate and processNewSegment in CommitLogSegmentManagerCDC class)

       

      I will attach patches later.

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            • Assignee:
              shichao.an Shichao An
              Reporter:
              shichao.an Shichao An
              Authors:
              Shichao An
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              Dates

              • Created:
                Updated: