Search Log Contents
Mezmo provides advanced capabilities for searching the contents of your logs. In this topic you'll find detailed information about search operators with examples of search queries, using Time Search, and how to work with special characters in your search queries.
Access Search
- Log in to app.mezmo.com.
- In the Search box at the bottom of the log viewer, enter your query.
- Select the Timeframe that you want to search.
- Select if you want to search Live log data, or historical.
- In the Viewer Tools menu, enter any text you want highlighted in the search results.

Search bar in the Mezmo Web App
Search
Introduction
A query is composed of terms, phrases, and operators. In this example,
ClassCastException OR "Null Pointer Exception"
the query can be broken up into the following:
ClassCastException
is a term."Null Pointer Exception"
is a phrase.OR
is an operator.This query will filter for any lines that contains the text
ClassCastException
,Null Pointer Exception
, or both.
Terms
A term will match any line that contains that term anywhere within the line. By default every term match is case insensitive and a prefix match. This behavior can be changed with the case sensitive operator and exact match operators respectively.
For example all of these queries,
BAR
barrier
===barrier
will match the following line:
We really like the barrier reef
AND Operator
Implicit AND
Any whitespace between terms is implicitly interpreted as AND
.
For example, the query file does not exist
will return any log containing all four words, regardless of their order. To search for the exact phrase, surround it in double quotes, "file does not exists"
The only exception is when using lists, which treat whitespace as a part of the search term. Learn more in (Link Removed).
Explicit AND
You can also add AND as an operator to your search query to explicitly combine terms.
healthcheck AND -successful
This example query will look for the word healthcheck
AND log lines that do not contain the word successful
.
Explicit AND
You can also add AND as an operator to your search query to explicitly combine terms.
healthcheck AND -successful
This example query will look for the word healthcheck
AND log lines that do not contain the word successful
.
OR Operator
Specifying the OR operator returns results with either term.
healthcheck OR ping
This example query will return all log lines that contain the word healthcheck
or contain the word ping.
Chained Operators
You can chain operators together for specific searches. See the section Order of Operators for more information on the order of operator execution.
healthcheck -successful OR ping
This query example will return lines with healthcheck
, then lines that do not have the word successful
or ping
.
Grouping
Use parentheses to explicitly specify operator precedence for your search terms, Queries in parenthesis are executed first.
app:memo -("success" OR "waiting")
This will search in the Mezmo app and exclude log line containing success or waiting.
Order of Operations
Search query operations are executed in this order:
( )
Grouping-
NotOR
AND
or implicit white space between terms
The query me myself OR I
is equivalent to me AND (myself OR I)
since OR operators have higher precedence than AND operators.
The query (me myself) OR I
is equivalent to (me AND myself) OR I
since grouping operators have higher precedence than OR operators.
All remaining operators are at the same precedence as the grouping operators.
Time Search
You can search for logs that were generated during specific or broad time frames in the Jump to Timeframe area in the log View. You can use both text and numeric values, For example:
last friday
yesterday 1pm
5:4am
2/24 2:30pm
Special Characters
Escaping Special Characters
Put words in parenthesis to escape special characters such as white space. Unless escaped, terms are combined by whitespace and use AND to search.
This query example will look for 403 Forbidden
and login:
"403 Forbidden" login
Symbols
By default, all symbols in queries are matched exactly.
In this example, the query will return all logs that contain the term %VARIABLE%
:
%VARIABLE%
Filter Logs
Filters can be found on the Views page in your Mezmo app.
- Tags - A tag can be used to group lines and more than one tag can be applied to a given line.
- Source - Contains a list of your logging sources. A source can be a host, computer, virtual machine, or Heroku app. Source metadata such as IP address or OS may be displayed with the source.
- App - Contains a list of logging buckets. An app can represent a log file, program or container. Typically, log lines within an app are inherently similar.
- Level - Contains a list of parsed log levels, such as
INFO
,DEBUG
, orERROR
. Log levels are automatically parsed from log lines using standard log level detection and common patterns.
Use Filters
To use filters, click on the desired filter drop-down menu and tick the checkboxes of the entries you are interested in. Selecting more than one checkbox within a filter will include log lines that belong to any of the selected entries. Selecting checkboxes in more than one filter, such as selecting 1 app and 1 source, will return log lines that match both that app and that source.
- Selected entries within such as selecting two sources, use OR
- Selected entries across filters such as selecting a source and an app, use AND
(host1 AND website) OR (host1 AND react_app) OR (host2 AND website) OR (host2 AND react_app).
If you select two sources, host1
and host2
, then select two apps, website
and react_app
. Log lines matching these conditions will be returned.
(host1 AND website) OR (host1 AND react_app) OR (host2 AND website) OR (host2 AND react_app).