> For the complete documentation index, see [llms.txt](https://docs.postgresql.tw/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.postgresql.tw/reference/reference-server/app-pgwalsummary.md). # pg\_walsummary ### pg\_walsummary pg\_walsummary — print contents of WAL summary files ### Synopsis `pg_walsummary` \[*`option`*...] \[*`file`*...] ### Description pg\_walsummary is used to print the contents of WAL summary files. These binary files are found in the `pg_wal/summaries` subdirectory of the data directory, and can be converted to text using this tool. This is not ordinarily necessary, since WAL summary files primarily exist to support [incremental backup](/server-administration/backup/continuous-archiving.md#BACKUP-INCREMENTAL-BACKUP), but it may be useful for debugging purposes. A WAL summary file is indexed by tablespace OID, relation OID, and relation fork. For each relation fork, it stores the list of blocks that were modified by WAL within the range summarized in the file. It can also store a "limit block," which is 0 if the relation fork was created or truncated within the relevant WAL range, and otherwise the shortest length to which the relation fork was truncated. If the relation fork was not created, deleted, or truncated within the relevant WAL range, the limit block is undefined or infinite and will not be printed by this tool. ### Options `-i`\ `--individual` : By default, `pg_walsummary` prints one line of output for each range of one or more consecutive modified blocks. This can make the output a lot briefer, since a relation where all blocks from 0 through 999 were modified will produce only one line of output rather than 1000 separate lines. This option requests a separate line of output for every modified block. `-q`\ `--quiet` : Do not print any output, except for errors. This can be useful when you want to know whether a WAL summary file can be successfully parsed but don't care about the contents. `-V`\ `--version` : Display version information, then exit. `-?`\ `--help` : Shows help about pg\_walsummary command line arguments, and exits. ### Environment The environment variable `PG_COLOR` specifies whether to use color in diagnostic messages. Possible values are `always`, `auto` and `never`. ### See Also [pg\_basebackup](/reference/reference-client/app-pgbasebackup.md), [pg\_combinebackup](/reference/reference-client/app-pgcombinebackup.md) *** 原文：[PostgreSQL 18.6 Documentation](https://www.postgresql.org/docs/18/app-pgwalsummary.html)（英文原文，待翻譯） --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.postgresql.tw/reference/reference-server/app-pgwalsummary.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.