Hello Experts,
How can time information in the SQL cache (M_SQL_PLAN_CACHE) be interpreted?
Thanks in advance.
SOLUTION
Tables like M_SQL_PLAN_CACHE, M_SQL_PLAN_CACHE_RESET and HOST_SQL_PLAN_CACHE contain several Time-Related columns and it is not always clear how to interpret them:
| Time column type | Description |
| CURSOR |
Contains the overall cursor time including SAP HANA server execution time and client time Preparation time isn't included Mainly applies to SELECT and CALL operations, can be 0 for others (e.g. DML, DDL) If the client performs other tasks between fetches of data, the cursor time can be much higher than the SAP HANA server time. This can result in MVCC issues because old versions of data need to be kept until the execution is finished. |
| EXECUTION |
Contains the execution time (open + fetch + lock wait + close) on SAP HANA server side, does not include table load and preparation time |
| EXECUTION_OPEN |
Contains the open time on SAP HANA server side Includes the actual retrieval of data in case of column store accesses with early materialization |
| EXECUTION_FETCH |
Contains the fetch time on SAP HANA server side Includes the actual retrieval of data in case of row store accesses or late materialization |
| EXECUTION_CLOSE | Contains the close time on SAP HANA server side |
| TABLE_LOAD | Contains the table load time during preparation, is part of the preparation time |
| PREPARATION | Contains the preparation time |
| LOCK_WAIT |
Contains the transaction lock wait time, internal locks are not included |