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system.keeper_changelogs

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Description

This table does not exist if this node is not configured to run an in-process ClickHouse Keeper. It contains one row per Raft changelog file (changelog_<from>_<to>.bin[.zstd]) tracked by the in-process Keeper log store, including the active file currently being appended to.

Columns

  • from_log_index (UInt64) — First Raft log index in the file (inclusive).
  • to_log_index (UInt64) — Last Raft log index covered by the filename (inclusive). For the active file this is the rotation target and may be ahead of last_entry_index.
  • last_entry_index (Nullable(UInt64)) — Highest log index actually appended to this file. NULL if the active file has not received any entries yet or the file is broken.
  • entries (UInt64) — Number of entries appended to this file. ALIAS for ifNull(last_entry_index - from_log_index + 1, 0).
  • path (String) — File path on the disk.
  • disk_name (String) — Name of the disk holding the file.
  • size_bytes (UInt64) — Size of the file on disk.
  • modification_time (DateTime) — Last modification time of the file.
  • is_compressed (Bool) — File payload is zstd-compressed.
  • active (Bool) — This file is currently being appended to.
  • is_broken (Bool) — Trailing record was found corrupted at startup.

Example:

SELECT from_log_index, to_log_index, entries, path, active FROM system.keeper_changelogs ORDER BY from_log_index;
┌─from_log_index─┬─to_log_index─┬─entries─┬─path───────────────────────────┬─active─┐
│              1 │         1000 │    1000 │ changelog_1_1000.bin.zstd      │ false  │
│           1001 │         2000 │     537 │ changelog_1001_2000.bin.zstd   │ true   │
└────────────────┴──────────────┴─────────┴────────────────────────────────┴────────┘
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