def process_linkprop_update(ir_stmt: irast.MutatingStmt, ir_expr: irast.Set,
wrapper: pgast.Query,
dml_cte: pgast.CommonTableExpr, *,
ctx: context.CompilerContextLevel) -> None:
"""Perform link property updates to a link relation.
:param ir_stmt:
IR of the statement.
:param ir_expr:
IR of the UPDATE body element.
:param wrapper:
Top-level SQL query.
:param dml_cte:
CTE representing the SQL UPDATE to the main relation of the Object.
"""
toplevel = ctx.toplevel_stmt
rptr = ir_expr.rptr
ptrref = rptr.ptrref
if ptrref.material_ptr:
ptrref = ptrref.material_ptr
target_tab = relctx.range_for_ptrref(ptrref,
include_overlays=False,
ctx=ctx)
dml_cte_rvar = pgast.RelRangeVar(
relation=dml_cte,
alias=pgast.Alias(aliasname=ctx.env.aliases.get('m')))
cond = astutils.new_binop(
pathctx.get_rvar_path_identity_var(dml_cte_rvar,
ir_stmt.subject.path_id,
env=ctx.env),
astutils.get_column(target_tab, 'source', nullable=False),
op='=',
)
targets = []
for prop_el, shape_op in ir_expr.shape:
assert shape_op is qlast.ShapeOp.ASSIGN
ptrname = prop_el.rptr.ptrref.shortname
with ctx.new() as input_rel_ctx:
input_rel_ctx.expr_exposed = False
input_rel = dispatch.compile(prop_el.expr, ctx=input_rel_ctx)
targets.append(pgast.UpdateTarget(name=ptrname.name,
val=input_rel))
updstmt = pgast.UpdateStmt(relation=target_tab,
where_clause=cond,
targets=targets,
from_clause=[dml_cte_rvar])
updcte = pgast.CommonTableExpr(query=updstmt,
name=ctx.env.aliases.get(
ptrref.shortname.name))
toplevel.ctes.append(updcte)
def scan_check_ctes(
stmt: pgast.Query,
check_ctes: List[pgast.CommonTableExpr],
*,
ctx: context.CompilerContextLevel,
) -> None:
if not check_ctes:
return
# Scan all of the check CTEs to enforce constraints that are
# checked as explicit queries and not Postgres constraints or
# triggers.
# To make sure that Postgres can't optimize the checks away, we
# reference them in the where clause of an UPDATE to a dummy
# table.
# Add a big random number, so that different queries should try to
# access different "rows" of the table, in case that matters.
base_int = random.randint(0, (1 << 60) - 1)
val: pgast.BaseExpr = pgast.NumericConstant(val=str(base_int))
for check_cte in check_ctes:
# We want the CTE to be MATERIALIZED, because otherwise
# Postgres might not fully evaluate all its columns when
# scanning it.
check_cte.materialized = True
check = pgast.SelectStmt(
target_list=[
pgast.ResTarget(val=pgast.FuncCall(name=('count', ),
args=[pgast.Star()]), )
],
from_clause=[
relctx.rvar_for_rel(check_cte, ctx=ctx),
],
)
val = pgast.Expr(kind=pgast.ExprKind.OP,
name='+',
lexpr=val,
rexpr=check)
update_query = pgast.UpdateStmt(
targets=[
pgast.UpdateTarget(name='flag',
val=pgast.BooleanConstant(val='true'))
],
relation=pgast.RelRangeVar(
relation=pgast.Relation(schemaname='edgedb', name='_dml_dummy')),
where_clause=pgast.Expr(
kind=pgast.ExprKind.OP,
name='=',
lexpr=pgast.ColumnRef(name=['id']),
rexpr=val,
))
stmt.append_cte(
pgast.CommonTableExpr(query=update_query,
name=ctx.env.aliases.get(hint='check_scan')))
def process_update_body(ir_stmt: irast.MutatingStmt, wrapper: pgast.Query,
update_cte: pgast.CommonTableExpr,
range_cte: pgast.CommonTableExpr, *,
ctx: context.CompilerContextLevel):
"""Generate SQL DML CTEs from an UpdateStmt IR.
:param ir_stmt:
IR of the statement.
:param wrapper:
Top-level SQL query.
:param update_cte:
CTE representing the SQL UPDATE to the main relation of the Object.
:param range_cte:
CTE representing the range affected by the statement.
"""
update_stmt = update_cte.query
assert isinstance(update_stmt, pgast.UpdateStmt)
external_updates = []
toplevel = ctx.toplevel_stmt
toplevel.ctes.append(range_cte)
toplevel.ctes.append(update_cte)
with ctx.newscope() as subctx:
# It is necessary to process the expressions in
# the UpdateStmt shape body in the context of the
# UPDATE statement so that references to the current
# values of the updated object are resolved correctly.
subctx.path_scope[ir_stmt.subject.path_id] = update_stmt
subctx.rel = update_stmt
subctx.expr_exposed = False
for shape_el in ir_stmt.subject.shape:
ptrref = shape_el.rptr.ptrref
updvalue = shape_el.expr
ptr_info = pg_types.get_ptrref_storage_info(ptrref,
resolve_type=True,
link_bias=False)
if ptr_info.table_type == 'ObjectType' and updvalue is not None:
with subctx.newscope() as scopectx:
# First, process all internal link updates
updtarget = pgast.UpdateTarget(
name=ptr_info.column_name,
val=pgast.TypeCast(arg=dispatch.compile(updvalue,
ctx=scopectx),
type_name=pgast.TypeName(
name=ptr_info.column_type)))
update_stmt.targets.append(updtarget)
props_only = is_props_only_update(shape_el, ctx=subctx)
ptr_info = pg_types.get_ptrref_storage_info(ptrref,
resolve_type=False,
link_bias=True)
if ptr_info and ptr_info.table_type == 'link':
external_updates.append((shape_el, props_only))
if not update_stmt.targets:
# No updates directly to the set target table,
# so convert the UPDATE statement into a SELECT.
from_clause: typing.List[pgast.BaseRangeVar] = [update_stmt.relation]
from_clause.extend(update_stmt.from_clause)
update_cte.query = pgast.SelectStmt(
ctes=update_stmt.ctes,
target_list=update_stmt.returning_list,
from_clause=from_clause,
where_clause=update_stmt.where_clause,
path_namespace=update_stmt.path_namespace,
path_outputs=update_stmt.path_outputs,
path_scope=update_stmt.path_scope,
path_rvar_map=update_stmt.path_rvar_map.copy(),
view_path_id_map=update_stmt.view_path_id_map.copy(),
ptr_join_map=update_stmt.ptr_join_map.copy(),
)
# Process necessary updates to the link tables.
for expr, props_only in external_updates:
process_link_update(ir_stmt=ir_stmt,
ir_set=expr,
props_only=False,
wrapper=wrapper,
dml_cte=update_cte,
iterator_cte=None,
is_insert=False,
ctx=ctx)
def process_update_body(
ir_stmt: irast.MutatingStmt,
wrapper: pgast.Query,
update_cte: pgast.CommonTableExpr,
typeref: irast.TypeRef,
*,
ctx: context.CompilerContextLevel,
) -> None:
"""Generate SQL DML CTEs from an UpdateStmt IR.
:param ir_stmt:
IR of the statement.
:param wrapper:
Top-level SQL query.
:param update_cte:
CTE representing the SQL UPDATE to the main relation of the Object.
:param typeref:
The specific TypeRef of a set being updated.
"""
update_stmt = update_cte.query
assert isinstance(update_stmt, pgast.UpdateStmt)
external_updates = []
with ctx.newscope() as subctx:
# It is necessary to process the expressions in
# the UpdateStmt shape body in the context of the
# UPDATE statement so that references to the current
# values of the updated object are resolved correctly.
subctx.parent_rel = update_stmt
subctx.expr_exposed = False
for shape_el, shape_op in ir_stmt.subject.shape:
ptrref = shape_el.rptr.ptrref
updvalue = shape_el.expr
ptr_info = pg_types.get_ptrref_storage_info(ptrref,
resolve_type=True,
link_bias=False)
if ptr_info.table_type == 'ObjectType' and updvalue is not None:
with subctx.newscope() as scopectx:
val: pgast.BaseExpr
if irtyputils.is_tuple(shape_el.typeref):
# When target is a tuple type, make sure
# the expression is compiled into a subquery
# returning a single column that is explicitly
# cast into the appropriate composite type.
val = relgen.set_as_subquery(
shape_el,
as_value=True,
explicit_cast=ptr_info.column_type,
ctx=scopectx,
)
else:
if (isinstance(updvalue, irast.MutatingStmt)
and updvalue in ctx.dml_stmts):
with scopectx.substmt() as relctx:
dml_cte = ctx.dml_stmts[updvalue]
wrap_dml_cte(updvalue, dml_cte, ctx=relctx)
pathctx.get_path_identity_output(
relctx.rel,
updvalue.subject.path_id,
env=relctx.env,
)
val = relctx.rel
else:
val = dispatch.compile(updvalue, ctx=scopectx)
val = pgast.TypeCast(arg=val,
type_name=pgast.TypeName(
name=ptr_info.column_type))
if shape_op is qlast.ShapeOp.SUBTRACT:
val = pgast.FuncCall(
name=('nullif', ),
args=[
pgast.ColumnRef(name=(ptr_info.column_name, )),
val,
],
)
updtarget = pgast.UpdateTarget(
name=ptr_info.column_name,
val=val,
)
update_stmt.targets.append(updtarget)
props_only = is_props_only_update(shape_el, ctx=subctx)
ptr_info = pg_types.get_ptrref_storage_info(ptrref,
resolve_type=False,
link_bias=True)
if ptr_info and ptr_info.table_type == 'link':
external_updates.append((shape_el, shape_op, props_only))
if not update_stmt.targets:
# No updates directly to the set target table,
# so convert the UPDATE statement into a SELECT.
from_clause: List[pgast.BaseRangeVar] = [update_stmt.relation]
from_clause.extend(update_stmt.from_clause)
update_cte.query = pgast.SelectStmt(
ctes=update_stmt.ctes,
target_list=update_stmt.returning_list,
from_clause=from_clause,
where_clause=update_stmt.where_clause,
path_namespace=update_stmt.path_namespace,
path_outputs=update_stmt.path_outputs,
path_scope=update_stmt.path_scope,
path_rvar_map=update_stmt.path_rvar_map.copy(),
view_path_id_map=update_stmt.view_path_id_map.copy(),
ptr_join_map=update_stmt.ptr_join_map.copy(),
)
toplevel = ctx.toplevel_stmt
toplevel.ctes.append(update_cte)
# Process necessary updates to the link tables.
for expr, shape_op, _ in external_updates:
process_link_update(
ir_stmt=ir_stmt,
ir_set=expr,
props_only=False,
wrapper=wrapper,
dml_cte=update_cte,
iterator_cte=None,
is_insert=False,
shape_op=shape_op,
source_typeref=typeref,
ctx=ctx,
)
