Question
How elastic search works?
We are upgrading from Pega 7.1.7 to Pega 7.1.9 and changing the indexing mechanism from lucene to elastic.
We previously used to have customised solution where the searching of indexes used to be directly from each node to the shared mount accessible on all the nodes.
With elastic search we would like to use the distributed way.
Few questions:-
1. What is the minimum number of nodes that needs to serve as indexing nodes?
2. Host nodes for indexing will be used for both generation and retrieval as well?
3. Would like to understand how the search works with elastic indexes from a node that is not the host node. Does it check initially whether the location is directly accessible or always goes to the host nodes?
1. Depends on your work load. If you have enabled WO- indexing and lot of work objects are being created / touched distributing the load across a 2 - 3 indexing hosts is ideal. This helps FTSIncrementalIndexer agent from backing out indexing events.
2. Yes. The search query in any node will internally end up in any of the index hosts.
3. Please refer to link - https://www.elastic.co/guide/en/elasticsearch/guide/current/_distributed_nature.html