Fix guide for benchmarking

Author: jungmair

docs/GettingStarted/Benchmarking.md

@@ -9,25 +9,53 @@ LingoDB supports common OLAP benchmarks such as TPC-H, TPC-DS, JOB and SSB.
 * Do *not* manually create Apache Arrow files, but instead use the `sql` command to define tables and import data. If you miss relevant metadata information (e.g., primary keys), LingoDB will not be able to apply many optimizations and performance will be suboptimal.
 * Use a release build of LingoDB for benchmarking. Debug builds are significantly slower.
 
-## Data Generation
-For some benchmarks, the LingoDB repository contains scripts to generate data and load them:
+
+## Manual steps
+### Data Generation
+For some benchmarks, the LingoDB repository contains scripts to generate data:
 ```sh
-# LINGODB_BINARY_DIR is the directory containing at least the `sql` binary
-# OUTPUT_DIR is the directory where the database should be stored
+# DATA_DIR is the directory where the csv files should be stored
 # SF is the scale factor, e.g., 1 for 1GB, 10 for 10GB, etc.
 
 # Generate TPC-H database
-bash tools/generate/tpch.sh LINGODB_BINARY_DIR OUTPUT_DIR SF
+bash tools/generate/tpch.sh DATA_DIR SF
 # Generate TPC-DS database
-bash tools/generate/tpcds.sh LINGODB_BINARY_DIR OUTPUT_DIR SF
+bash tools/generate/tpcds.sh DATA_DIR SF
 # Generate JOB database
-bash tools/generate/job.sh LINGODB_BINARY_DIR OUTPUT_DIR
+bash tools/generate/job.sh DATA_DIR
 # Generate SSB database
-bash tools/generate/ssb.sh LINGODB_BINARY_DIR OUTPUT_DIR SF
+bash tools/generate/ssb.sh DATA_DIR SF
+```
+
+### Data Loading 
+```sh
+# DB_DIR is the directory where the final database files should be stored
+cd DATA_DIR
+[LINGODB_BINARY_DIR]/sql DB_DIR < [REPO_ROOT]/resources/sql/tpch/initialize.sql # replace tpch with tpcds, job, ssb ...
 ```
+
+## Makefile target
+There is a convenience Makefile target for both generating and loading a set of datasets.
+```sh
+make resources/data/[NAME]-[SF]/.stamp
+
+# For example
+
+make resources/data/tpch-1/.stamp
+make resources/data/tpch-10/.stamp
+make resources/data/tpcds-1/.stamp
+make resources/data/ssb-1/.stamp
+
+make resources/data/job/.stamp
+
+```
+This will prepare the requested dataset (with scale factor) in the `resources/data/[NAME]-[SF]` directory
+
+## Running LingoDB
+
 Afterward, queries can be for examle run with the `sql` command that also reports execution times when the `LINGODB_SQL_REPORT_TIMES` environment variable is set:
 ```sh
-LINGODB_SQL_REPORT_TIMES=1 sql OUTPUT_DIR
+LINGODB_SQL_REPORT_TIMES=1 sql DB_DIR
 sql>select count(*) from lineitem;
 |                         count  |
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