Minor fixes to README (#64)

1. Remove a duplicate sentence.
2. Replace backquote of the sql argument with single quote (backquote in bash is for command substitution).
3. Since #62, the `--worker-pool-min` is a new arg without default value and need to be provided in the TPC example commands to run.

Author: vmingchen

README.md

@@ -64,8 +64,6 @@ Then build the project with the following command:
 maturin develop # --release for a release build
 ```
 
-- In the `examples` directory, run
-
 ## Example
 
 - In the `examples` directory, run
@@ -77,15 +75,15 @@ RAY_COLOR_PREFIX=1 RAY_DEDUP_LOGS=0 python tips.py --data-dir=$(pwd)/../testdata
 - In the `tpch` directory, use `make_data.py` to create a TPCH dataset at a provided scale factor, then
 
 ```bash
-RAY_COLOR_PREFIX=1 RAY_DEDUP_LOGS=0 python tpc.py --data=file:///path/to/your/tpch/directory/ --concurrency=2 --batch-size=8182 --qnum 2
+RAY_COLOR_PREFIX=1 RAY_DEDUP_LOGS=0 python tpc.py --data=file:///path/to/your/tpch/directory/ --concurrency=2 --batch-size=8182 --worker-pool-min=10 --qnum 2
 ```
 
 To execute the TPCH query #2. To execute an arbitrary query against the TPCH dataset, provide it with `--query` instead of `--qnum`. This is useful for validating plans that DataFusion Ray will create.
 
 For example, to execute the following query:
 
 ```bash
-RAY_COLOR_PREFIX=1 RAY_DEDUP_LOGS=0 python tpc.py --data=file:///path/to/your/tpch/directory/ --concurrency=2 --batch-size=8182 --query `select c.c_name, sum(o.o_totalprice) as total from orders o inner join customer c on o.o_custkey = c.c_custkey group by c_name limit 1`
+RAY_COLOR_PREFIX=1 RAY_DEDUP_LOGS=0 python tpc.py --data=file:///path/to/your/tpch/directory/ --concurrency=2 --batch-size=8182 --worker-pool-min=10 --query 'select c.c_name, sum(o.o_totalprice) as total from orders o inner join customer c on o.o_custkey = c.c_custkey group by c_name limit 1'
 ```
 
 To further parallelize execution, you can choose how many partitions will be served by each Stage with `--partitions-per-worker`. If this number is less than `--concurrency` Then multiple Actors will host portions of the stage. For example, if there are 10 stages calculated for a query, `concurrency=16` and `partitions-per-worker=4`, then `40` `RayStage` Actors will be created. If `partitions-per-worker=16` or is absent, then `10` `RayStage` Actors will be created.
@@ -95,7 +93,7 @@ To validate the output against non-ray single node datafusion, add `--validate`
 To run the entire TPCH benchmark use
 
 ```bash
-RAY_COLOR_PREFIX=1 RAY_DEDUP_LOGS=0 python tpcbench.py --data=file:///path/to/your/tpch/directory/ --concurrency=2 --batch-size=8182 [--partitions-per-worker=] [--validate]
+RAY_COLOR_PREFIX=1 RAY_DEDUP_LOGS=0 python tpcbench.py --data=file:///path/to/your/tpch/directory/ --concurrency=2 --batch-size=8182 --worker-pool-min=10 [--partitions-per-worker=] [--validate]
 ```
 
 This will output a json file in the current directory with query timings.