SAP HANA Extended SQL Executor (ESX) FAQs
1) Define SAP HANA Extended SQL Executor (ESX)?
SAP HANA Extended SQL Executor (ESX) is a front-end execution engine which replaced the row engine. it recovers the database request from session level and assign it to lower-level engines such HEX engine, join engine or calculation engine:
2) What are some important benefits of ESX?
The following are the benefits and components are provided by ESX:
- It minimizes the runtimes and memory requirements by pipelining
- It uses itabs as common format, therefore, making communication with other engines becomes easy.
- It is light-weight and separate library which reduces dependencies from other components
3) How to control the usage of ESX?
Following parameter can be used on a global level in order to activate or deactivate ESX
- indexserver.ini -> [sql] -> esx_level
The user can also USE_ESX_PLAN and NO_USE_ESX_PLAN hints on statement level in order to activate or deactivate ESX
4) How to trace ESX?
Please, following parameters exist to trace ESX:
| Parameter | Value | Details |
| indexserver.ini -> [trace] -> esx_dump_plan | debug | Detailed ESX plan information including node operation tree and input itab type information (available with SAP HANA 2.0 >= SPS 03) |
5) What are the various indications that ESX is used for processing database request?
The modules related ESX in the call stack of threads indicate the use of ESX such as:
- ESX::EsxFieldExpression
- ESX::ItabMaterialize::open
- ESX::NestedLoopJoin::open
- ESX::OperatorNode::fetchAll
- ESX::ParallelItabBuildJob::runInternal
- ESX::Plan::execute
- ESX::Plan::generateItab
- ESX::Plan::getOutputItab
- ESX::Select::open
- ESX::Utils::setValues
- ESX::Window::fetch
- ESX::Window::increaseFetchThreads
- ESX::Window::prepareFetchInfo
- ptime::Esx_search::do_open
- ptime::PtimeEsxPlan::fetch
6) Mention some known issues related to ESX?
The following known issues listed below in the table exist in relation to ESX:
| Problem | Impacted Revisions |
| Termination with unable to update attribute store | 2.00.020 |
| Crash in ESX::ParallelItabBuildJob::runInternal | 2.00.020 |
| Termination with NOT NULL constraint violation | <= 2.00.022 |
| Crash in ESX::Window::prepareFetchInfo | <= 2.00.022 |
| Termination with unknown attribute error | <= 2.00.023 |
| Memory Leak in Pool/ESX When Using PlanViz | <= 2.00.023 |
| Crash in UnifiedTable::Alphanum::set | <= 2.00.024.01 2.00.030 |
7) How can we configure ESX?
Please use these following SAP HANA parameters in order adjust the ESX behaviour:
| Parameter | Default | Details |
indexserver.ini -> [sql] -> esx_level |
1 |
Activation (1) or deactivation (0) of ESX |
indexserver.ini -> [sql] -> use_esx_project |
true |
If set to true, ESX can write search results directly into a stream without using an itab |