Enabling Scalable Real-Time Sensor Stream Processing Across Decentralized Privacy-Preserving Storage Solutions

. 2026 Sep 15;26(18):5846. doi: 10.3390/s26185846

Algorithm 1 RSP-QL Query Reuse Compatibility Check

Require:
Existing executing query $Q_{e}$ and candidate query $Q_{c}$
Ensure:
Returns $t r u e$ only when the result stream of $Q_{e}$ can be reused for $Q_{c}$
1:
procedure CanReuseQuery( $Q_{e}, Q_{c}$ )
2:
$P_{e} \leftarrow$ ParseRSPQL $(Q_{e})$
3:
$P_{c} \leftarrow$ ParseRSPQL $(Q_{c})$
4:
if not SupportedQueryShape( $P_{e}$ ) or not SupportedQueryShape( $P_{c}$ ) then
5:
return $f a l s e$
6:
end if
7:
$W_{e} \leftarrow$ GetWindowDefinition(P_e)
8:
$W_{c} \leftarrow$ GetWindowDefinition(P_c)
9:
if $W_{e} . stream \neq W_{c} . stream$ then
10:
return $f a l s e$
11:
end if
12:
if $W_{e} . range \neq W_{c} . range$ or $W_{e} . step \neq W_{c} . step$ then
13:
return $f a l s e$
14:
end if
15:
if $W_{e} . name \neq W_{c} . name$ then
16:
return $f a l s e$
17:
end if
18:
$B_{e} \leftarrow$ ExtractBasicGraphPattern(P_e)
19:
$B_{c} \leftarrow$ ExtractBasicGraphPattern(P_c)
20:
$(matches, μ) \leftarrow$ MatchGraphPatterns(B_e, B_c)
21:
if not $matches$ then
22:
return $f a l s e$
23:
end if
24:
if not SameResultSemantics( $P_{e}, P_{c}, μ$ ) then
25:
return $f a l s e$
26:
end if
27:
return $t r u e$
28:
end procedure