app.component.html:

<div class="col-12 p-0">
            <mat-paginator class="paginator col-12" (page)="pageEvent = 
                   getServerData($event)"
                           [length]="totalRecords"
                           [pageSize]="search.size"
                           [pageSizeOptions]="[10, 20, 50, 100]" showFirstLastButtons> 
             </mat-paginator>

</div>

app.component.ts:

 ::ng-deep .mat-select-panel-wrap {
 flex-basis: 100%;
 padding-bottom: 40px !important;
 padding-left: 12px !important;
 }

when i am selecting 10,20,50 the mat-select was working fine and even after selecting 100 its displays 100 rows.But when the select value was on 100 and i try to select the mat-select was going above as shown in the image.

https://stackblitz.com/edit/angular-mat-paginator-jhx2jf?file=app/table-pagination-example.ts

Thanks.