#
# Checking dd string memory use with PFS
#
# Create and drop a basic table to populate the
# shared cache with DD table objects.
CREATE TABLE t1(i int);
DROP TABLE t1;
#
# Truncating memory events table to avoid noise
TRUNCATE TABLE performance_schema.memory_summary_global_by_event_name;
#
# Saving baseline
CREATE TABLE baseline AS
SELECT * FROM performance_schema.memory_summary_global_by_event_name
WHERE EVENT_NAME = 'memory/sql/dd::String_type';
#
# Creating basic table
CREATE TABLE t1(i int);
#
# Collect PFS info after create
CREATE TABLE after_create AS
SELECT * FROM performance_schema.memory_summary_global_by_event_name
WHERE EVENT_NAME = 'memory/sql/dd::String_type';
#
# Create diffs table for simpler analysis
CREATE TABLE diffs (EVENT_NAME VARCHAR(512), COUNT_ALLOC_DIFF BIGINT,
COUNT_FREE_DIFF BIGINT,
SUM_NUMBER_OF_BYTES_ALLOC_DIFF BIGINT,
SUM_NUMBER_OF_BYTES_FREE_DIFF BIGINT) AS
SELECT baseline.EVENT_NAME,
after_create.COUNT_ALLOC - baseline.COUNT_ALLOC AS COUNT_ALLOC_DIFF,
after_create.COUNT_FREE - baseline.COUNT_FREE AS COUNT_FREE_DIFF,
after_create.SUM_NUMBER_OF_BYTES_ALLOC -
baseline.SUM_NUMBER_OF_BYTES_ALLOC AS SUM_NUMBER_OF_BYTES_ALLOC_DIFF,
after_create.SUM_NUMBER_OF_BYTES_FREE -
baseline.SUM_NUMBER_OF_BYTES_FREE AS SUM_NUMBER_OF_BYTES_FREE_DIFF
FROM after_create, baseline
WHERE after_create.EVENT_NAME = baseline.EVENT_NAME;
#
# Create percents table for simpler analysis
CREATE TABLE percents (EVENT_NAME VARCHAR(512), ALLOC_PCT DECIMAL(10,3),
FREE_PCT DECIMAL(10,3), BYTES_ALLOC_PCT DECIMAL(10,3),
BYTES_FREE_PCT DECIMAL(10,3));
INSERT INTO percents
SELECT
baseline.EVENT_NAME,
100 * ROUND(diffs.COUNT_ALLOC_DIFF / baseline.COUNT_ALLOC, 5),
100 * ROUND(diffs.COUNT_FREE_DIFF / baseline.COUNT_FREE, 5),
100 * ROUND(diffs.SUM_NUMBER_OF_BYTES_ALLOC_DIFF / baseline.SUM_NUMBER_OF_BYTES_ALLOC, 5),
100 * ROUND(diffs.SUM_NUMBER_OF_BYTES_FREE_DIFF / baseline.SUM_NUMBER_OF_BYTES_FREE, 5)
FROM diffs, baseline
WHERE diffs.EVENT_NAME = baseline.EVENT_NAME;
#
# Checking increase in the number of allocations (threshold 19%)
#
SELECT
baseline.EVENT_NAME AS 'PSI MEMORY EVENT NAME',
baseline.COUNT_ALLOC AS 'BASE ALLOC',
after_create.COUNT_ALLOC AS 'POST ALLOC',
diffs.COUNT_ALLOC_DIFF AS DELTA,
percents.ALLOC_PCT AS PCT_CHANGE,
'Exceeds threshold of +19%' AS REASON
FROM baseline JOIN (after_create, diffs, percents) ON
(baseline.EVENT_NAME = after_create.EVENT_NAME AND
baseline.EVENT_NAME = diffs.EVENT_NAME AND
baseline.EVENT_NAME = percents.EVENT_NAME)
WHERE percents.ALLOC_PCT > 19;
PSI MEMORY EVENT NAME	BASE ALLOC	POST ALLOC	DELTA	PCT_CHANGE	REASON
#
# Checking increase in the number of bytes allocated (threshold 25%)
#
SELECT
baseline.EVENT_NAME AS 'PSI MEMORY EVENT NAME',
baseline.SUM_NUMBER_OF_BYTES_ALLOC AS 'BASE ALLOC BYTES',
after_create.SUM_NUMBER_OF_BYTES_ALLOC AS 'POST ALLOC BYTES',
diffs.SUM_NUMBER_OF_BYTES_ALLOC_DIFF AS DELTA,
percents.BYTES_ALLOC_PCT AS PCT_CHANGE,
'Exceeds threshold of +29%' AS REASON
FROM baseline JOIN (after_create, diffs, percents) ON
(baseline.EVENT_NAME = after_create.EVENT_NAME AND
baseline.EVENT_NAME = diffs.EVENT_NAME AND
baseline.EVENT_NAME = percents.EVENT_NAME)
WHERE percents.BYTES_ALLOC_PCT > 29;
PSI MEMORY EVENT NAME	BASE ALLOC BYTES	POST ALLOC BYTES	DELTA	PCT_CHANGE	REASON
#
# Cleaning up
DROP TABLE percents;
DROP TABLE diffs;
DROP TABLE after_create;
DROP TABLE t1;
DROP TABLE baseline;