Maximum dbcache too small #31326

1. 
   pbies commented at 10:31 pm on November 19, 2024: none

   Is there an existing issue for this?

   • I have searched the existing issues

   Current behaviour

   28.0 gives ‘out of space’ and hangs when dbcache is set to 16384 and full chainstate -reindex is run.

   Expected behaviour

   Should -reindex complete the reindexing.

   Steps to reproduce

   Have whole blockchain on disk, txindex=1, dbcache=16384 and reindex whole chainstate with command line -reindex option.

   Relevant log output

   2024-11-18T17:15:31Z Cache size (16396074160) exceeds total space (16395641600)

   How did you obtain Bitcoin Core

   Pre-built binaries

   What version of Bitcoin Core are you using?

   28.0

   Operating system and version

   Windows 10 Pro x64 PL

   Machine specifications

   No response

2. 
   pbies commented at 10:33 pm on November 19, 2024: none

   Seems like the issue is also here: https://github.com/bitcoin/bitcoin/issues/27599
3. 
   achow101 commented at 10:53 pm on November 19, 2024: member

   The “hanging” is caused by the cache flushing. For a 16GB cache, that can take quite a while, depending on your hardware. The only solution is to be patient and wait for it to finish flushing. If you turn on additional debug logging, you should see consistent log lines about it flushing entries to disk.

   Increasing the cache will only make that “hanging” worse as the cache will be even bigger and so even more data to be flushed at once.

   #28358 dropped the dbcache limit, but that won’t make this go away, it just means that once the node exits IBD, it’ll spend a long time flushing the cache.

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