Unified Index

This applies to the search and capabilities in Tiki to filter (search filters, permissions, etc) content. It is important if not critical to keep a fresh Unified-Index as Tiki rely on the freshness of the Unified-Index to display and filter content.

Tiki can support multiple search engines internally. Each of those will have different capabilities and limitations. The default engine should provide capabilities good enough for small and medium sites. Larger sites may need additional infrastructure to get the most performance. Please see: Unified Index Comparison

Fields

Below is a matrix between the fields and the object types.

Legend:

*) Tokenized - as in decomposed in words for full text search

Tracker Fields

The indexing for tracker fields will vary depending on the field type. As a general rule, tracker_field_PERMNAME/ID will be used as the field and will be sortable. However, there are a few exceptions:

• Image and File fields are not indexed
• TextArea is not sortable

Multilingual fields are indexed as multiple fields

• The main one (tracker_field_PERMNAME/ID) contains all languages
• tracker_field_PERMNAME/ID_lang contains one language only (tracker_field_12_fr for example)

Rating and related fields store as multiple fields

• tracker_field_PERMNAME/ID contains the average
• tracker_field_PERMNAME/ID_sum contains the vote totals
• tracker_field_PERMNAME/ID_count contains the number of votes

Items List and Item Link fields

• tracker_field_PERMNAME/ID_text contains the text instead of the IDs of the linked/listed items

Language of the tracker item

• If a language field is set for the tracker item, that language is indexed as the item language, i.e. the language field.

Some used in buildQuery/tiki-searchindex.php (need explanation on whether these are real fields or just helpers):
type: refers to object_type
deep: if this is set, categories will be considered deep-categories
autocomplete: Will search for items with title starting with this

Rebuild search index

Tiki is applying filters (and partially permissions to view) and in some case reading directly information from the Unified-Index. This allow very good performances and a lot of flexibility. Therefor, it is important to keep a fresh Unified-Index. Features but also plugins and module will also relies on the freshness of the Unified-Index to display updated content (pages content, items, user informations, etc).

You can see when the index was last fully rebuilt usually by start a rebuild process from he Tiki interface (see below).

In recent Tiki version the index is stored in the database and you can rebuild (refresh) the Unified-Index with different method.

From the Tiki interface

It is possible to rebuild the Unified-Index from a browser. However due to possible timeout during long operation it is recommended to do this ONLY on relatively small Tiki (based on the number and the size of your Tiki objects). For medium to high load sites, it is strongly recommended do that operation from the command line (much less limited), see the next paragraph.

• From the admin dashboard, on the main tiki menu click on the item Control Panels, then click on the Search panel. At the top of the page you will find a Rebuild Index button.
• From your URL address bar tiki-admin.php?page=search&rebuild=now

From the command line

The search index can be rebuilt manually from the command line or you can use the Tiki Scheduler since Tiki17 - see Rebuild the Unified Index with log sample or a Cron job since Tiki9 to runs the command automatically - see Cron Job to Rebuild Search Index.

Below are the commands that may be used to rebuild the index. Check Console documentation.

You can also rebuild it using the unified console.php command, with the appropriate parameters. For example:

Basic command

php console.php index:rebuild

<-- or -->

php console.php i:r

<-- or add visual verbose, to follow what is going on -->

php console.php i:r -p

Multitiki sites

For multitiki sites, you can rebuild with commands like:

php console.php index:rebuild --site=site1.example.com  
php console.php index:rebuild --site=site2.example.com  
...

Successful rebuild

If the rebuild is successful a message like the following will be produced (for cron jobs, this can usually be sent to you via email as part of automatically running the command):

Started rebuilding index...

Unified search
--------------

Engine: MySQL, version 5.7.34
Indexed
  trackeritem: 210
  tracker: 13
  trackerfield: 104
  article: 67
  file: 285
  file gallery: 20
  comment: 0
  user: 8
  group: 7
  wiki page: 55
  category: 18
Rebuilding index done
Index: index_6291d4b25591f

Execution Statistics
---------------------

Execution time: 16 secs
Current Memory usage: 51.0 MiB
Memory peak usage before indexing: 22.5 MiB
Memory peak usage after indexing: 51.2 MiB
Number of queries: 12383

Troubleshooting

If the rebuild is unsuccessful, instead of the above message you may get a message that indicates there has been an internal server error, or it may say "Rebuild in progress." This may be because the rebuild process uses more memory or takes more time than allowed by the server's php settings. Such settings can be changed on the fly as part of the rebuild command - examples of how to do this are shown below.

Not enough memory

Increase memory limit
One way to increase memory is to change the memory_limit php setting as follows (this example changes the memory limit to 4 gigabytes while the rebuild process is running):

php -dmemory_limit=4G console.php i:r --log

You could also direct php to use a specific php.ini file, where there may be a higher memory limit setting or no limit. In this case you would use the -c parameter followed by the path to the php.ini file, as in the example below:

php -c /etc/php5/cli/php.ini console.php i:r --log

Timeout error

Increase maximum execution time
Getting an internal server error may indicate the rebuild process takes longer than the max_execution_time php setting. That can be increased as part of the command as shown below where the max execution time is set to 300 seconds, or 5 minutes. (This command is also increasing the memory limit as described above):

php -dmemory_limit=4G -dmax_execution_time=300 console.php i:r --log

Force rebuild

When the rebuild is unsuccessful with a "Rebuild in progress" message, this usually means that the rebuild failed previously in the middle of the process, leaving a temporary folder called temp/unified-index-new on the server. When a new rebuild is started and the program sees this folder, it thinks there is a rebuild already in progress and will stop. You can either delete this folder before rebuilding again or include the --force parameter in the rebuild command as follows:

php -dmemory_limit=4G -dmax_execution_time=300 console.php i:r --force --log

Log to review possible problems with content

php console.php i:r -p --log

Several index_ files in the database

Typically happening when using the same database over and over you may end with several indexes in your database.
We provide a developer tool to clean properly this issue.
You need to be the web user and use bash to run the script.

bash doc/devtools/clear_mysql_search_indexes.bash

You need to rebuild your index after the operation.

MySQL limits for very big numbers of tracker fields

How to detect

If Unified Search is configured with the MySQL Full Text Search engine, you might encounter a failure to reindex with the following symptoms:

• php console index:rebuild stops without displaying the list of indexing statistics:

php console index:rebuild
[14 mai 2020 09:26 EDT] Started rebuilding index...
Unified search engine: MySQL, version 10.1.45-MariaDB
(it takes a very long time and in the end nothing shows up)

If you investigate with producing a log it ends this way:

php console.php index:rebuild --log 
[14 mai 2020 16:10 EDT] Started rebuilding index... logging to file: temp/Search_Indexer_mysql_database_name_console.log
Unified search engine: MySQL, version 10.1.45-MariaDB
(it takes a very long time and in the end nothing shows up)

tail temp/Search_Indexer_mysql_database_name_console.log 
…
2020-05-14T16:21:47-04:00 ERR (3): Indexing failed while processing "2512" (type trackeritem) with the error "Could not perform index modification: Too many columns"
2020-05-14T16:21:47-04:00 ERR (3): WARNING: PDO::query(): SQLSTATE[HY000]: General error: 1117 Too many columns {"code":null,"file":"/path/to/tikiroot/lib/core/TikiDb/Pdo.php","line":104}
2020-05-14T16:21:47-04:00 INFO (6): addDocument trackeritem 2513 {"memoryUsage":"46.5 MiB"}
2020-05-14T16:21:47-04:00 ERR (3): Indexing failed while processing "2513" (type trackeritem) with the error "Could not perform index modification: Too many columns"
2020-05-14T16:21:47-04:00 ERR (3): WARNING: PDO::query(): SQLSTATE[HY000]: General error: 1117 Too many columns {"code":null,"file":"/path/to/tikiroot/lib/core/TikiDb/Pdo.php","line":104}
2020-05-14T16:21:47-04:00 INFO (6): addDocument trackeritem 2514 {"memoryUsage":"46.5 MiB"}

Technical explanation (thanks Victor)

Solutions

The following options in Control panels → Search help for this situation:

• MySQL use short field names
  Due to frm file constraints, number of search fields that one index can hold is usually limited to about 1500. This can be exceeded if you have numerous tracker fields. Enabling this option will try to shorten the field names internally that should allow you to use 300-500 more fields. Switching this option requires full index rebuild.
  Summary: This makes no difference in how you use Tiki.
• Don't index non searchable fields
  Indexing will skip adding all tracker fields that are not marked as "searchable". This will free index space but also make it impossible to use those fields in search index queries.
  Summary: You need to review the Searchable property of you tracker fields. A full index rebuild will be necessary after changes in the tracker fields Searchable properties.

Hint: If the first option is enough for your site, you may ignore the second one.

Indexing log common error troubleshooting

When rebuilding your index use the following command to create a log file.
Note you need to point to the PHP for the PHP version your Tiki uses.

php console.php i:r -p --log

In the log you may see some error, this is an attempt to help and diagnose the possible issues.

Unified Index storage in the database (MySQL full-text search)

By design the unified-index store data in the MySQL database using MyISAM no matter if your Tiki uses innoDB or MyISAM (not all versions of InnoDB offer FULLTEXT).

Duplicate unified-index table

For some reasons you may found that your database has several index (tables like index_...alphanumeric...).
This happen when they were issues rebuilding the index or when moving and upgrading the database (Tiki upgrade).

You can delete those tables (always consider saving a backup of your data prior any work) and rebuild the unified-index. Tiki will recreate and relink everything properly. You can find information about the unified-index in use at the Search control panel, General settings under Unified search index.

Related

• Cron Job to Rebuild Search Index
• PluginList
• PluginCustomSearch
• Unified Search

Developer Notes

See https://dev.tiki.org/Unified-Index#Developer_Notes.

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