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| -rw-r--r-- | docs/source/sqlext.rst | 43 |
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diff --git a/docs/source/sqlext.rst b/docs/source/sqlext.rst index 221b100..3b0ee75 100644 --- a/docs/source/sqlext.rst +++ b/docs/source/sqlext.rst @@ -47,6 +47,14 @@ and maximum number of bytes returned by the server, grouped by IP address: ;SELECT c_ip, avg(sc_bytes), max(sc_bytes) FROM access_log GROUP BY c_ip +.. note:: + + For reference, the PRQL query would look like this: + + .. code-block:: elm + + from access_log | stats.by c_ip {average sc_bytes, max sc_bytes} + After pressing :kbd:`Enter`, SQLite will execute the query using **lnav**'s virtual table implementation to extract the data directly from the log files. Once the query has finished, the main window will switch to the DB view to @@ -71,6 +79,39 @@ The DB view has the following display features: the `jget`_ function. +PRQL Support (v0.12.1+) +----------------------- + +`PRQL <https://prql-lang.org>`_ is an alternative database query language +that compiles to SQLite. You can enter PRQL in the database query prompt +and lnav will switch accordingly. A major advantage of using PRQL is that +lnav can show previews of the results of the pipeline stages and provide +better tab completion options. + +A PRQL query starts with the :code:`from` keyword that specifies the table +to use as a data source. The next stage of a pipeline is started by +entering a pipe symbol (:code:`|`) followed by a +`PRQL transform <https://prql-lang.org/book/reference/stdlib/transforms/index.html>`_. +As you build the query in the prompt, lnav will display any relevant +help and preview for the current and previous stages of the pipeline. + +The following is a screenshot of lnav viewing a web access log with a +query in progress: + +.. figure:: ../assets/images/lnav-prql-preview.png + :align: center + + Screenshot of a PRQL query in progress + +The top half of the window is the usual log message view. Below that is +the online help panel showing the documentation for the :code:`stats.count_by` +PRQL function. lnav will show the help for what is currently under the +cursor. The next panel shows the preview data for the pipeline stage +that precedes the stage where the cursor is. In this case, the +results of :code:`from access_log`, which is the contents of the access +log table. The second preview window shows the result of the +pipeline stage where the cursor is located. + Log Tables ---------- @@ -105,6 +146,8 @@ The following columns are builtin and included in a :code:`SELECT *`: an :code:`UPDATE` or the :ref:`:comment<comment>` command. :log_tags: A JSON list of tags for the message. This column can be changed by an :code:`UPDATE` or the :ref:`:tag<tag>` command. + :log_annotations: A JSON object of annotations for this message. + This column is populated by the :ref:`:annotate<annotate>` command. :log_filters: A JSON list of filter IDs that matched this message The following columns are builtin and are hidden, so they will *not* be |